Seagrass as Climate-Smart Insulation for the Tropics: Key Insights from Numerical Simulations and Field Studies

Abstract

Seagrass ecosystems provide essential ecological services and are increasingly recognized for their potential as sustainable building insulation. While prior studies have examined seagrass insulation in temperate climates, its suitability for tropical construction remains largely unexplored. This study assesses the insulation performance, practical challenges, and adoption barriers of seagrass insulation in tropical climates, using building physics simulations and structured expert interviews, with case studies in Seychelles and Auroville, India. Simulation results indicate that seagrass insulation with its high specific heat capacity effectively reduces overheating risks and demonstrates consistently low mould-growth potential under persistently humid tropical conditions. Despite these technical advantages, expert interviews reveal significant non-technical barriers, including negative public perception, regulatory uncertainties, and logistical complexities. Seychelles faces particular hurdles such as limited coastal storage capacity and stringent environmental regulations. In contrast, Auroville emerges as an ideal demonstration site due to its strong sustainability culture and openness to innovative building materials. The study further identifies that integrating seagrass insulation into a structured, regulated supply chain—from sustainable harvesting and processing to quality assurance—could simultaneously enhance ecosystem conservation and material availability. Implementing a harvesting framework analogous to sustainable forestry could ensure environmental protection alongside supply stability. The findings emphasize the urgent need for targeted awareness initiatives, regulatory alignment, and economic feasibility assessments to overcome barriers and enable wider adoption. Overall, this research highlights seagrass insulation as a promising, climate-positive construction material with strong potential under tropical conditions, provided that identified logistical, societal, and regulatory challenges are addressed through dedicated research, stakeholder collaboration, and practical pilot projects.

1. Introduction

Seagrass stores over 18% of the carbon sequestered by oceans worldwide, although it occupies just 0.1% of the ocean surface. Globally, marine ecosystems such as seagrass, mangroves, and salt marshes store over 30,000 megatons (MT) of carbon [1,2,3,4]. More recently, Seychelles has committed to protect at least 50% of its seagrass beds by 2025 [2]. At the end of its life cycle, seagrass is often found as washed-up material on the beach. Washed-up seagrass on Seychelles beaches and on holiday beaches in general is often considered a nuisance and treated as litter [2,5].

India’s seagrass meadows are primarily located in the Palk Bay and Gulf of Mannar (Tamil Nadu), the Gulf of Kachchh (Gujarat), Chilika Lake (Odisha), and around the Andaman, Nicobar, and Lakshadweep Islands [6]. These ecosystems play a crucial role in coastal biodiversity, supporting species like the endangered dugong (Dugong dugon) and acting as critical carbon sinks [7]. However, habitat degradation due to anthropogenic activities, climate change, and coastal development has led to significant seagrass loss, particularly along the west coast [8]. Conservation efforts, including mapping and monitoring through satellite remote sensing, are essential for preserving these ecologically valuable marine habitats [6].

Figure 1 illustrates the global seagrass diversity and distribution. Small island states like the Seychelles, but also countries with long coastlines such as India, are particularly affected by the impacts of climate change. The rise in sea level has been accelerating for years, which is already leading to a decline in habitat areas and biodiversity [9].

The tangible impacts of the climate crisis necessitate a paradigm shift, particularly in the tropical construction sector, which faces unique challenges such as high humidity, thermal stress, and extreme weather. Addressing these demands the development of environmentally sustainable solutions, especially hygrothermally resilient, regionally available, and low-emission insulation materials, which are essential for improving climate adaptability in the built environment. One of the biggest influences has the construction sector, which was responsible for 37% of global energy-related CO₂ emissions in 2020. Just under 30% of this came from the production of building materials. This corresponds to 3.2 gigatons (GT) of CO₂ emissions. The United Nations Environment Programme (UNEP) therefore states in its latest global report that the use of low-emission building materials in terms of CO₂ will be a necessity in the future [3,4].

This is where the need for new, low-emission building materials and the availability of previously unused seagrass (Posidonia oceanica), which is often regarded as beach pollution both in the Seychelles and in India, come together. This work therefore examines the technical suitability of seagrass as an emission-negative insulation material in the tropics, and the barriers to its use in the Seychelles and the experimental city of Auroville (India). Unlike previous studies [1,3,5,6,7,8,10,11,12,13,14,15,16,17,18], which focused primarily on temperate climates, this work uniquely targets tropical conditions, providing valuable new insights into the suitability of seagrass insulation for humid and hot climates.

In general, bio-based insulation materials—such as hemp fibre, cellulose, sheep’s wool, coconut fibre, and seaweed—are increasingly recognized for their low embodied energy, carbon sequestration potential, and end-of-life recyclability. Comprehensive reviews document hemp and cellulose’s high renewability and favourable thermal conductivity, achieving up to 30% lower lifecycle carbon footprints compared to mineral wool or polystyrene [19,20,21,22,23,24]. Sheep’s wool insulation further reduces ecological impact through minimal processing and inherent moisture buffering [25]. In tropical climates, coconut fibre exhibits excellent moisture resilience and thermal inertia, while seaweed- and seagrass-based products have demonstrated effective hygrothermal regulation under high humidity and solar loads [26,27,28,29,30,31]. Such diverse bio-based options support circular-economy principles and align with UNEP’s call for low-emission, resilient construction in warm, humid regions [3,4].

Building regulations in Seychelles are largely based on the national specifications of the Seychelles Planning Authority (SPA) and the Seychelles Bureau of Standards (SBS). These standards are adapted to the tropical climate and geographical conditions of the Seychelles. Auroville, on the other hand, is known for its experimental architecture and the use of innovative building materials. The settlement in southern India uses sustainable and environmentally friendly construction methods, often incorporating alternative materials such as clay, ferrocement, recycled materials and local natural materials.

This article introduces an issue that has been largely neglected. To date, there has been no research or projects dealing with seagrass insulation in the tropics. In contrast, analyses on the use of seagrass insulation materials have already been carried out in subtropical and temperate climates, which in some places has already led to the use of seagrass as a resource in construction. Despite considerably increasing interest in the seagrass ecosystem over the last few years, mainly the seagrass resources of the Mediterranean, the Atlantic, and the Pacific have been investigated [32]. This underlines the necessity and relevance of this work.

In the Seychelles, the hotel sector is particularly relevant for evaluating insulation strategies, as private residential buildings typically rely on large windows and doors for natural ventilation rather than air conditioning [33]. Under these naturally ventilated conditions, building insulation currently provides limited benefits. However, hotels commonly use air conditioning systems extensively, making them ideal candidates for insulation to significantly reduce cooling energy requirements, a benefit already well-documented in tropical regions [34]. Given the country’s prominence as a tourist destination with numerous hotels, Seychelles provides a practical and impactful context to investigate the effectiveness of seagrass insulation.

In Auroville, India, the research explores the application of seagrass insulation specifically for metal roofs. Due to its high thermal capacity, seagrass effectively mitigates overheating caused by intense solar radiation, resulting in improved indoor climate stability and reduced energy consumption for cooling. Additionally, seagrass exhibits natural moisture resistance, thereby minimizing mould formation and condensation issues beneath metal roofs. Its fibrous structure also provides notable sound-absorbing properties, reducing noise disturbance from heavy rainfall and strong winds [35].

Insulating buildings with natural insulation materials not only saves energy and thus CO₂ emissions during operation, but also during production, transport, and recycling. By using local resources, long transport routes are avoided [36]. This positive effect is reinforced by the remoteness of the Seychelles.

The overall aim of the study is to assess the potential of seagrass as an insulating material in the tropics. The main objective is therefore divided into two subobjectives:

The first sub-objective is to evaluate the physical building performance of seagrass insulation by determining key material parameters, including thermal conductivity, specific heat capacity, moisture absorption, and water vapor diffusion resistance. Using input values that closely reflect real conditions, both thermal and hygrothermal simulations will be conducted. Particular focus is placed on assessing how the high humidity levels characteristic of tropical climates affects the performance and durability of seagrass as an insulating material.

The second sub-objective involves compiling and synthesizing the knowledge, experience, and perspectives of relevant stakeholders, spanning fields such as seagrass ecology, insulation technology, architecture, and civil engineering. Particular attention is given to the regional contexts of the Seychelles and the experimental city of Auroville. Expert interviews, based on a questionnaire developed through an extensive literature review, aim to identify key barriers to adoption, logistical and regulatory challenges, and stakeholder perceptions of the material’s technical feasibility. These insights contribute to bridging the gap between the technical performance of seagrass insulation and its practical implementation in real-world construction contexts.

2. Materials and Methods

The Seychelles Archipelago and Auroville in southern India were chosen to study. The climate of the Seychelles is characterised by two monsoon winds and high humidity throughout the year, averaging 80%. Temperatures vary between 24 °C and 32 °C throughout the year. Auroville also has a tropical climate with high humidity, especially during the monsoon season from June to November. Temperatures are usually between 24 °C and 36 °C, with cooling sea breezes from the Bay of Bengal tempering the climate, especially in the winter months.

2.1. Calculation of the Insulation Properties

For the calculation of the insulation properties, the three calculation software programs Ubakus (version 08.2022) [37], Delphin (version 6.1.0), and WUFI (version 6.2) were compared at the beginning. WUFI was excluded because no licence was available in this case. Finally, Delphin and Ubakus were examined by applying for licences and creating user accounts for both programs. The advantage of using Delphin results from the more realistic calculation of the states. In contrast to Ubakus, Delphin uses an unsteady calculation method. This means that dynamic developments are mapped. Ubakus, on the other hand, calculates with stationary temperatures and humidities. However, the program simulates daily temperature fluctuations in 10 min steps, and thus checks the building component for potential humidity problems. In addition, thermal calculations for winter and summer thermal insulation can be carried out. This is done according to the Glaser method. The Glaser method examines constructions for possible formation of condensation with stationary conditions. In favour of Ubakus is the fact that own building materials can be added and temperature and humidity can be adjusted for indoor and outdoor areas. The limitation of stationary conditions was considered less serious, as the tropical climate is characterised by comparatively constant conditions. According to Ubakus, the possible deviations of the result from reality are more pessimistic in normal cases. The decisive reason for the final choice of Ubakus is that in Delphin only weather data from Europe can be reckoned with [38].

The first step was to create a new insulation material in the program that adequately represents the seagrass insulation material in terms of its physical building properties. Mean values were formed from the collected literature values. If a parameter was given with a range (e.g., bulk density: 65–75 kg/m³), the mean value was used in each case. An exception was the water vapour diffusion resistance, as this can be entered with a range in Ubakus. The calculation of the mean values results in the basic parameters shown in

Table 1. Comparison of typical hygrothermal properties for seagrass insulation versus other bio-based and conventional materials [5,15,39,40].

Material	Bulk Density ρ [kg/m³]	Thermal Conductivity λ [W/(m·K)]	Specific Heat Capacity c [J/(kg·K)]	Fire Class	Vapour Diffusion Factor μ
Zostera marina (Seagrass)	65–75	0.039–0.046	2500	B2 (normal combustibility)	1–2
Cellulose	25–90	0.040–0.045	1500	B1, B2	1–2
Flax	20–40	0.040–0.050	1400	B2 (normal combustibility)	1–2
Hemp	20–40	0.040–0.080	1700	B2 (normal combustibility)	1–2
Sheep’s wool	20–80	0.040–0.045	1000	B2 (normal combustibility)	1–2
Rock wool	25–220	0.035–0.050	840	A1, A2 (non-combustible)	1–2
Foam glass	105–165	0.040–0.055	840	A1, A2 (non-combustible)	∞
Expanded Polystyrene (EPS)	15–40	0.032–0.038	1300	E (sometimes D)	20–100
Glass wool (fiberglass)	12–48	0.032–0.034	840	A1 (non-combustible)	1
Rigid PU foam	30–45	0.022–0.028	1400	E/B3	30–100

for use in Ubakus. These averaged values appear in Table 1 alongside analogous data for other bio-based (cellulose, flax, hemp, wool) and conventional (rock wool, EPS, glass wool, PU foam, foam glass) insulations. Notably, seagrass combines a relatively low thermal conductivity (0.039–0.046 W/(m·K)) with a high specific heat capacity (2500 J/(kg·K)), offering superior thermal inertia compared to EPS (≈0.032–0.038 W/(m·K), 1300 J/kg·K) and glass wool (≈0.032–0.034 W/(m·K), 840 J/kg·K), while maintaining good moisture regulation (µ = 1–2) and standard fire performance (B2). These characteristics make seagrass insulation uniquely well-suited for stabilizing indoor temperatures in humid tropical climates.

Two main variants were created for the structure of the component under investigation. In addition, two sub-variants were defined for one variant. The two sub-variants are only intended to investigate the effect of the vapour barrier and the effect of the rear ventilation, which is why they are only applied to one variant. Lime-cement plaster was chosen as the interior plaster, as it is also suitable for humid air [41]. For the exterior plaster, a water-repellent mineral plaster was chosen in view of the temporary high rainfall. The thickness of 3 mm is prespecified for the selected material. For the vapour barrier, a vapour barrier with the sd-value of 100 m was chosen. The parameters for temperature and humidity in the interior were specified as 25 °C and 50% humidity.

While roof (Figure 2) and wall insulation share the fundamental goal of reducing heat transfer and improving energy efficiency, their thermal dynamics differ due to variations in solar exposure, heat flow direction, and moisture risks. To a certain extent, key findings from wall insulation studies—such as thermal resistance, moisture management, and material behaviour—can inform roof insulation strategies. For instance, materials with high specific heat capacity, such as seagrass insulation, which has demonstrated effectiveness in delaying heat transfer through walls, could also be beneficial for roofs by stabilizing indoor temperatures and reducing cooling loads. Similarly, insights into vapor diffusion resistance and moisture retention from wall insulation applications can help predict condensation risks in roof assemblies. However, roofs experience higher direct solar radiation, greater diurnal temperature fluctuations, and different ventilation requirements compared to walls. Thus, while wall insulation principles provide a useful foundation, dedicated roof insulation studies must account for these unique thermal physics factors to optimize performance in different climate conditions.

• Variant 1: Façade insulation

In Figure 3, the entered structure of the first variant can be seen. The total thickness of the element is 56.6 cm.

Pine wood was selected as the wood species, as it is frequently used according to [20]. The other wood species mentioned are not available in Ubakus. Reinforced concrete was chosen as the load-bearing wall, as it has a high heat storage capacity and can withstand very strong compressive forces [44].

• Variant 1.1: Façade insulation without vapour barrier

This sub-variant is identical to variant 1 except for the vapour barrier s_d = 100 (layer 6), which is removed from the structure. This is to investigate which differences occur compared to variant 1 and which effects the vapour barrier consequently has on the entire construction.

• Variant 1.2: Façade insulation without rear ventilation

For this sub-variant, the same applies as for variant 1.1. Variant 1 is adopted except for the rear ventilation with room air (layer 2).

• Variant 2: Wooden stud frame

Figure 4 shows the construction of the second variant. The total thickness of the construction is 48.1 cm.

For the reasons mentioned above, pine wood was chosen again. The rest of the structure followed the structure of the timber frame with seagrass, with the exception of the position of the vapour barrier and the rear ventilation. In Figure 5, the structure of Variant 2 is shown in 3D for better illustration.

With the input of the structures and the previous inputs of the climate data, the indoor climate, and the parameters for the creation of the new insulation material, the Ubakus software can calculate the insulation properties and moisture contents of the constructions.

2.2. Expert Interviews

Within each sector, as many experts as possible were requested in order to obtain a high significance of the results. Which persons were considered experts is sector-specific.

In the tourism sector, the largest luxury hotels in the Seychelles were requested (25 hotels in total). This can be explained by several motives. On the one hand, the focus was placed on large hotels, as contact was sought with senior engineers at each hotel and it was assumed that small hotels or guesthouses were less likely to have employed internal engineers. Mainly luxury hotels were requested, as hotels with air-conditioned rooms were of particular interest for the survey. In addition, the selection of hotels was made under the assumption that larger hotels are more likely to have the financial means to spend possible additional costs for alternative insulation materials in a next project. The selection did not take into account the sustainability efforts of the hotels, as the results should not be biased. Some of the hotels surveyed were traced via the website of the travel service provider Agoda, as there the search could be limited to four- and five-star hotels with air conditioning.

In the seagrass insulation sector, expert selection was primarily based on the findings of the preceding literature review. All known manufacturers and suppliers of seagrass insulation were contacted. Additionally, two experts who had overseen projects involving seagrass insulation were approached. A research institution specializing in alternative insulation materials was also contacted (five persons in total).

In the field of biology, several authors frequently cited in the literature review were contacted. Additionally, members and heads of various tropical research centres within the biological sciences were approached. Biologists based in the Seychelles were also included among those contacted (seven persons in total).

For the construction company sector, all companies were filtered by category on the SeyBusiness.com website. Sixteen construction companies were found in the category “Construction”. One of them had limited itself exclusively to renovation work, which is why it was not relevant any further. The remaining fifteen companies were requested as experts for the interviews in the construction company sector.

In the field of architecture, all architects in Auroville who had worked in the past with environmentally friendly building methods were asked. Seven expert interviews were conducted.

Table 2. Expert selection overview for Seychelles case study.

Sector	Expert Selection Criteria	Sources/ Method	Inclusion Criteria	Exclusion Criteria
Tourism	Large luxury hotels with air-conditioned rooms; likely to employ technical staff and afford alternative materials	Filtered search on https://www.agoda.com	4–5 star hotels, presence of air-conditioned rooms, assumed access to engineering/technical staff	Small hotels, guesthouses, focus on sustainability (to avoid bias)
Seagrass Insulation	Manufacturers, suppliers, and project-experienced experts in seagrass insulation; one research institution	Based on literature review; direct contacts	Active involvement in seagrass insulation production, supply, or project supervision	Lack of direct connection to seagrass insulation
Biology	Frequently cited authors; members and directors of tropical research centres; biologists in the Seychelles	Derived from literature review and institutional affiliations	Frequent citation in literature, institutional role in tropical biology, geographic relevance (Seychelles)	Authors with marginal relevance or outside the tropical biology field
Construction	Construction companies active in building (excluding renovation-only firms)	Derived from literature review and institutional affiliations	Listed under “Construction” on SeyBusiness.com, involved in general construction projects	Companies focused solely on renovation work

provides an overview of the sector-specific expert selection process, including the selection criteria, sources, and defined inclusion and exclusion parameters for each interview group.

3. Results

3.1. Simulation Results for Seagrass Insulation Assemblies

Although the following results focus on wall insulation, some insights apply to roof insulation. Seagrass’s high heat capacity and low thermal conductivity suggest potential for reducing heat gain in roofs, especially in trA review of natural bio-based insulation materialsopical climates. However, roofs face higher solar exposure, greater temperature fluctuations, and different moisture dynamics. While the material’s performance in humidity control and thermal resistance is promising, additional studies considering solar radiation, ventilation, and structural load are needed to confirm its effectiveness for roof insulation.

In the following, the calculation results of the variants explained in Section 3.1 are presented. For this purpose, in

Table 3. Absolute thermal resistance and U-value of all calculated variants (modified according to [37]).

Variant	Absolute Thermal Resistance Rt [m2·K/W]	U-Value [W/(m2·K)]	Heat Storage Capacity of Entire Building Component [kJ/(m2·K)]
Variant 1	7.102	0.141	378
Variant 1.1	7.100	0.141	378
Variant 1.2	7.115	0.141	400
Variant 2	6.073	0.165	124

the calculated U-values (the overall heat transfer coefficient that measures how well a building element conducts heat) of the different constructions are compiled. The reciprocal value of the U-value, the absolute thermal resistance R_t, is also shown for illustration purposes.

• Results Variant 1

In variant 1, no condensation occurs, which is why mould formation is not to be expected in this construction. In Figure 6, the relative humidity (in %) inside the building component can be seen. The relative humidity indicates the percentage of the air that is saturated with water vapour.

It can be seen that the humidity from the outside drops significantly directly at the vapour barrier (6). A humidity of less than 55% can be maintained throughout. In Figure 7 and Figure 8, the temperature curve is shown once in section and once in colour in the plan view inside the component. The damping effect of the seagrass insulation is clearly visible.

• Results Variant 1.1

In variant 1.1 without a vapour barrier, there is also no condensation, which is why mould formation is not to be expected in the construction. However, it can be seen in Figure 9 that the relative humidity in the concrete element is significantly higher than in variant 1. At the end, a value of about 80% is reached.

Nevertheless, a humidity of less than 55% can be maintained in the seagrass insulation material. The temperature curve within the component is shown in Figure 10.

In Figure 11, the temperature curve in the component can be seen in the plan view.

• Results Variant 1.2

Despite the removal of the rear ventilation, there is no condensation in variant 1.2. Mould growth is therefore not to be expected in the construction. The course of the relative humidity, which can be seen in Figure 12 is almost identical to variant 1.

• Results Variant 2

In variant 2, no condensation occurs, which is why mould formation is not to be expected in this construction. In Figure 13 on the left, the relative humidity (in %) inside the component is shown in section. The plan view of the component is shown on the right. The black bar in the right-hand picture symbolises the point at which the left-hand graph is measured.

It can also be seen in this variant that the humidity from the outside drops significantly directly at the vapour barrier (layer 7). The relative humidity does not exceed 55% at any point. In Figure 14, the temperature curve in the section inside the building component can be seen.

In Figure 15, the temperature curve in the component can be seen in the plan view.

It is clearly visible that the seagrass insulation material has an effect on course of the temperature, which is only increasing slowly from inside to outside.

3.2. Results from the Expert Interviews

Before the main statements from the interviews are presented, some particularities of the overall rather low response rate are briefly discussed.

3.2.1. Special Features on the Response Rate

The response to the requests for expert interviews in the case of the Seychelles was weak. However, there are clear differences between the sectors. In the seagrass insulation sector (S), three of five requested interviews could be conducted. Of these, two were conducted via extensive videoconferencing and one via email. In the biology sector (B), there were two acceptances out of seven requests. These were both conducted via videoconference. In the tourism sector Seychelles (H), out of 25 requested hotels, one hotel was interviewed. This was realised via e-mail contact. There was no reply to written queries on individual questions. Finally, no survey was conducted in the construction company sector (U) with 15 enquiries.

Overall, with six interviews conducted out of 52 requested experts in the case of the Seychelles, the acceptance rate is 12%. The reasons recorded for the refusals—if these were given—could be roughly divided into the categories “lack of time” and “no interest”. The number of refusals due to lack of time is about twice as high as the number of refusals due to lack of interest. However, it seems reasonable to assume that these statements do not necessarily always correspond to the truth. While acknowledging the low response rate (12%), we emphasize that the insights obtained from expert interviews are intended as qualitative, exploratory data, rather than statistically representative. Future research should adopt improved methods for stakeholder engagement, including personal outreach, follow-up protocols, or incentive-based participation to achieve higher response rates and enhance the robustness of conclusions.

In the case of Auroville, seven of the eleven architects contacted could be interviewed, giving an acceptance rate of 64%. The reason for the relatively high acceptance rate could be that Auroville is known for its experimental architecture and sustainable building methods. Architects there are often open to alternative materials and innovative solutions. Sustainability also plays a central role in Auroville. Seagrass, as a potentially environmentally friendly insulation material, has therefore attracted interest.

3.2.2. Experience and Key Figures of the Seagrass Industry

The following is a summary of the findings from discussions with various experts in the seagrass industry, none of whom work in the tropics. No experts in this field could be found in the Seychelles or in Auroville. The results are presented systematically according to the sequence in the process of seagrass use. Furthermore, botanical and ecological findings about seagrass from the interviews with the biologists are compiled. All interview partners were anonymised using a combination of letter and number, where the letter is the abbreviation for the respective sector.

• Collection process

In the case of expert S2, the collection process involves a tractor driving a few metres into shallow tidal zones or onto beach ramps to load the loosely floating seagrass, without entering open water. This is described as essential, as the seagrass is not contaminated with sand and thus no additional cleaning process is necessary. S2 also describes that the purity of the debris depends on the wind conditions. In the case of S3, a purity of over 90% is mentioned. Spatially, both of these observations refer to Denmark. Another possibility would be to collect the seagrass by hand, fork, and wheelbarrow.

• Treatment process

According to S2, the preparation process begins with the spreading of the collected material onto a free, directly adjacent field. Expert S3 also emphasises the availability of a free field directly next to the sites as an essential factor. Depending on the amount of rainfall, the material remains there for one to two weeks. It should be cleaned by the rain and finally dried. S3 describes the same process and says that one rainfall event is sufficient for cleaning. This would make the seagrass sufficiently pure for use as insulation material. S3’s description of the process mentions turning the material once in the field to allow it to dry completely. S2 describes that after this time the seagrass is pressed into bales and transported to the site of use. Thus, the only equipment mentioned as needed is the baler and a tractor for collection. Expert S3 mentions research on seagrass blow-in insulation material. For this, the material is finely chopped in the preparation process. However, measurements showed that seagrass loses its good insulating properties as a result.

• Quantity of material required

According to S1’s experience, a volume of 0.2 m³ and a mass of about 14 kg of seagrass insulation material is needed to insulate 1 m² of wall surface with a thickness of 20 cm. S2 referred to data from the website Seegrashandel.de, which in his experience correspond to reality. This information—converted to the above-mentioned area and thickness—amounts to about 8 kg of seagrass mass required for the insulation. Expert S3 spoke of a quantity of 8–9 t of seagrass for 100 m². Converted, this results in 80–90 kg per m². However, since the seagrass insulation in the construction described was used both inside and outside in large nets, the difference to the other figures is comprehensible.

• Areas of application

Both S1 and S2 stated that they have never had problems with seagrass in a finished construction. S3 had problems with leaks in the roof structure, but these were probably not related to the seagrass use. The parts of the building seen in Figure 16 are mentioned as suitable for insulation with seagrass.

The simplest installation option mentioned is the insulation of the upper storey ceiling. In a construction described by S3, the seagrass insulation was even used in the perimeter area. S2 named the following sequence from the outside to the inside as a suitable structure for retrofitting roof insulation: roof tiles, batten construction, foil, seagrass, foil, batten construction, wood fibre boards, plaster.

• Botanical and Ecological Findings

At the moment, there is a lot of research on the coastal ecosystems of Seychelles and specifically on seagrass. Before that, there were not many projects or research in this area. B2 believes that quantifiable results on Seychelles’ coastal ecosystems and their carbon storage capacity will be available within a year at the latest. According to B2, this could lead to the development of a so-called “carbon market” in Seychelles. B1 also estimated that such a market and the sale of carbon certificates could occur soon.

Expert B1 added that 95% of the carbon stored by seagrass is stored in the sediment. Seagrass meadows are renowned blue carbon ecosystems where the vast majority of stored carbon resides in the seabed rather than in the plants themselves. Multiple sources indicate that on the order of 90–95% of the total carbon in seagrass meadows is stored in the underlying sediments, with only a small fraction (5–10% or less) in the living biomass (leaves, roots, and rhizomes) [11,12,16,18]. Regarding the existing amount of Seychelles seagrass, B2 said that there is an estimate of 2.1 million ha, but he does not consider this to be realistic. B2 considered a quantity of 200,000 ha to be more plausible. Expert B1 also spoke of a seagrass area of 142,000 ha around the Seychelles. Most of the seagrass around the Seychelles is found in the Outer Islands. B1 also confirmed that seagrass can be found in large quantities along the coasts almost exclusively in the Outer Islands. This is also where 95% of the Seychelles’ seagrass stocks are found, but they are less diverse than the stocks in the Inner Islands. In the Inner Islands, the focus is mainly on industry, tourism, and land use, and less on the seagrass beds.

• Beach Wrack

Most seagrass accumulates during the southeast monsoon on Seychelles’ southeast-facing coasts. However, the amount of seagrass also depends on the growth rates of the seagrass and the type of seagrass. According to B2, large quantities of seagrass often wash up on Seychelles’ coasts in May. However, according to B2, seagrass also washes up in all other months. This is contradicted by B1, who commented that most of the seagrass drifts to the open sea and does not beach on the coasts. According to B1, Seychelles’ beach wrack consists mainly of seagrass. B1 saw the collection of the floating seagrass on the water surface as a possibility, as this also replaces a possible clean-up operation.

3.2.3. Challenges of the Use of Seagrass

This section summarises the challenges mentioned by the experts that could arise during production, use, approval, or marketing.

• Time Expenditure

Expert S2 stated as a disadvantage of insulation with seagrass that the processing of the insulation material in the construction contains a high time expenditure. Due to the presence of the material as loose fibres—instead of ready-made mats or boards, for example—the seagrass has to be installed by hand in small steps. In addition, the seagrass fibres cannot be blown in. S3 also saw the manual work as a disadvantage, but noted that this could be an opportunity for the Seychelles labour market. It is noted that the installation could become very cost-intensive if an external company is hired.

• Economic efficiency

Expert H1 stated that seagrass insulation is cost-effective due to the abundant stock. S3, on the other hand, said that seagrass is more expensive per kg than conventional insulation because the provision of field space for drying and cleaning the seagrass must also be remunerated. However, it was added that this could also be different in the Seychelles with different framework conditions. The factor of the transport route is also mentioned. The length of the transport is an important price indicator.

One idea from S3 is an agreement with the city or hotels. The principle is that the beaches used for tourism are cleaned by companies that are paid for it and are given the seagrass to use. This would start with a negative price as a basis, so to speak.

• Ecological Liabilities from Seagrass Use

Five of the six interviewees saw the ecological impact of using seagrass on the coastal system as a challenge. For example, H1 explained that any insulation material made from seagrass should be used carefully so that it does not adversely affect the ecosystem through possible pressure build-up. B1 saw the combination of the obligation to protect seagrass beds and mangrove forests with the use of seagrass as insulation material as critical and incompatible. S1 also expressed that the seagrass should actually be returned to the water, as microorganisms benefit from it. S2 also addressed the conflict of seagrass use with the protection of the coastal ecosystem. Ideally, the seagrass should remain on the coast or at least not be removed large-scale. As an alternative, S2 mentioned burying the beach wrack directly on site. This way, the beach would be “clean” for tourism purposes and yet the nutrients would not be removed from the ecosystem. B2 also saw a problem in the removal and use of seagrass, but did not consider it to be significant, as seagrass accumulates on very few beaches in the Seychelles anyway and is not removed.

B2 mentioned as a risk of using seagrass as insulation that it could lead to illegal and/or excessive harvesting of seagrass if it becomes a positive market trend and demand increases sharply as a result.

• Question of the Suitability of Seagrass on Tropical Islands

For S2, the question arose whether the conditions and properties of seagrass from the Seychelles are comparable to those from the Baltic Sea. He also mentioned the possible contamination with plastic, pollutants, or large amounts of algae, which would limit the suitability of seagrass as an insulating material in the tropics. B2 thought that there are big differences between seagrass in the tropics and seagrass in the temperate zone. B1 also thought that the various seagrass species differ significantly from each other, at least in terms of carbon storage capacity.

B1 saw the need for land and clean water for the processing of the seagrass insulation material as a further obstacle. These are essential resources for small tropical islands like the Seychelles. Also, the need for insulation in Seychelles was questioned, as private buildings are well-ventilated and built without insulation. Expert S3 disagreed, noting that especially in warmer climates, insulation can also protect against summer overheating.

• Regulatory and Business Hurdles

Due to strict biodiversity regulations in Seychelles, H1 saw an obstacle in the indirect use of the natural coastal site without an official permit. S1 agreed with this. It was expected that permits and a large organisation are needed for seagrass extraction. S2 also stated that, at least in Germany, loose seagrass may not be taken out of the water and that certain regulations also apply when collecting the material on the beach. B2 was of the opinion that regulations on the type and quantity of removal are necessary to protect the ecosystem from excessive use.

The company S1 described the biggest difficulties in setting up the business as financing and the numerous competitors in the insulation market. In addition, many common insulation materials are more strongly promoted by politics and lobbying. Furthermore, the process of certifying the insulation material is cost-intensive.

• General Reasons for low Market Share and Attention

As general reasons for the low share of seagrass in the insulation market and in the construction industry, H1 and S3 expressed that presumably many do not know that insulation with seagrass is a possibility, as it is a rather new topic. This was echoed by B2. The latter mentioned that the majority of construction services and labour in the construction industry in Seychelles are sourced from abroad, and that they may not yet be aware of seagrass use. Another possibility H1 saw is people’s fear of the high salinity of seagrass and its effects on the building. Furthermore, S2 addressed the bad image of seagrass as unwanted beach litter and pollution of the area.

S2 and S3 mentioned that, due to natural processes, shortages can easily occur, and this may be one reason why seagrass is not yet used as an insulating material on a large scale. According to S2, this dependence on natural processes is also the reason why seagrass can only remain a niche product as an insulating material. However, the amount that is washed up anyway could still be used. B1 took a more critical view and said that he does not see any potential in the commercial use of seagrass, as the amount of beach wrack washed up in the Seychelles is sparse and, if it is, it is contaminated with algae.

The risk of use is another aspect. Expert S3 explained that most companies tend to use the materials they know will work. The risk of using a new building material that has not yet been used much is too high for many. S3 believed that this attitude will not change unless it becomes necessary. In some countries, regulations and limits for CO₂ emissions per m² and year for the construction of a new building have already been decided. This would bring more attention and use to low-emission materials.

Findings from the interviews conducted with architects and builders in Auroville highlight several barriers to the adoption of seagrass as an insulation material in India. A key challenge is the strong reliance on conventional insulation solutions, particularly in roofing and wall applications. In contemporary Indian construction, expanded polystyrene (EPS) foam, extruded polystyrene (XPS), and polyurethane (PU) foam are the predominant choices due to their established supply chains, standardized performance metrics, and ease of integration with metal and concrete structures. While natural alternatives such as coconut fibre insulation exist, their application remains limited compared to synthetic options. The introduction of seagrass insulation is further complicated by market unfamiliarity, regulatory constraints, and a lack of certification processes within the Indian building sector.

Moreover, the interviews revealed that very few of the professionals consulted were familiar with seagrass as a building material, and only a handful had even seen seagrass along the Indian coastline. This general lack of awareness further exacerbates acceptance challenges, as industry stakeholders remain hesitant to adopt unproven materials without clear performance benchmarks and regulatory approvals.

Beyond material acceptance, architectural preferences in warm climates also influence insulation strategies. Rather than relying solely on thermal insulation, many designs incorporate passive cooling strategies such as double-layered roofing with natural ventilation, which reduces heat gain without requiring additional insulation materials. This approach is particularly advantageous as it also helps mitigate issues related to insect and rodent nesting, a common concern with organic insulation materials. As a result, seagrass insulation may need to be evaluated not only as a standalone solution but also in hybrid applications that complement passive cooling techniques.

Material availability was also identified as a key constraint. The seasonal and inconsistent accumulation of seagrass along Indian coastlines presents logistical challenges for large-scale adoption. Additionally, potential plastic contamination in beached seagrass necessitates rigorous processing and quality control measures to ensure material purity and consistent performance.

To facilitate wider acceptance of seagrass insulation, further research is required to quantify its thermal conductivity, fire resistance, and long-term durability in comparison to conventional insulation materials. Empirical studies, material standardization, and pilot projects demonstrating its practical integration in real-world building envelopes will be crucial in bridging the gap between material innovation and industry adaptation.

3.2.4. Opportunities Through Seagrass Insulation

• Seagrass Properties

Expert H1 saw the advantage of using seagrass insulation material in that seagrass naturally has a high salinity tolerance and the material is therefore not negatively affected by the high salinity of the coastal environment. The property of being the best summer thermal insulation is particularly emphasised by S1. For S2 and S3, important advantages are that seagrass is poorly combustible and vermin resistant. Another point that particularly stood out for S2 is that the seagrass insulation material can be installed by oneself. This saves costs for external companies. S2 stated that the expenses saved by internal labour are greater than the slightly higher price per kg of seagrass compared to conventional insulation materials.

• Ecological Advantages

S1 emphasised above all that seagrass has the lowest primary energy input of all insulation materials. In addition, it was mentioned that no additives are needed during production and the space requirement is very low. The entire life cycle is assessed as resource-friendly, since neither fertilisation nor watering is required. S2 also saw this as a major advantage: A usable insulating material is produced from the actual waste product with little energy. Another advantage mentioned by S1 and S2 is the simple separation in end-of-life scenarios and the possibility of reusability, for example as a soil additive. However, the material’s lifespan can be limited due to factors such as microbial degradation under prolonged exposure to moisture or damage resulting from improper installation. B2 explained that he even considers sustainable seagrass harvesting possible with some seagrasses. As an example, he mentioned seagrasses that serve as food for turtles, and yet grow again in the same place every year.

• Ideas of Dissemination and Use

Creating a more positive image of seagrass is the first sensible measure for S2. This should lead to people realising that the seagrass lying on the beach is not waste, but a resource. Finally, when buying seagrass insulation, one could introduce the option to support reforestation measures of seagrass meadows by means of a small additional expenditure. On the other hand, this could also be included directly in the purchase price, so that the continued existence of the seagrass is ensured despite its use.

• Positive Influence in Tourism

H1 was sure that hotels could increase the number of guests by acting sustainably. This ecotourism is the path that should also be taken for climate protection.

4. Discussion

4.1. Recommended Structure

From the results presented in Section 3.1, it can be deduced that with the given framework conditions and limitations due to the calculation software used, no damage is to be assumed in any of the four variants.

An examination of the U-values shows that all variants have very good insulating properties. The insulation properties of variants 1, 1.1, and 1.2 are even slightly better than the insulation properties of variant 2. By comparing the respective heat storage capacity of the entire building component, it can be seen that variant 2, with about one third of the heat storage capacity of the remaining variants, offers significantly worse protection against summer heat. Variant 1.2 has the highest summer thermal insulation with 400 kJ/(m²·K). However, all four variants achieve good results in this area in comparison with average values. An additional consideration of the life cycle assessment and greenhouse emissions, which would presumably be significantly better in variant 2, could be valuable for an overall assessment.

The results of the moisture protection calculation do not show the occurrence of condensation in any variant. This is a good indication that mould growth is not to be expected. Both the façade insulation with vapour barrier and rear ventilation (variant 1), the façade insulation with vapour barrier without rear ventilation (variant 1.2), and the timber beam construction with vapour barrier and rear ventilation (variant 2) have low air humidities of <55% within the building component. There are no significant differences between these variants in the temperature curve and the humidity curve in the building component. In variant 1.1, on the other hand, in which the vapour barrier was omitted, clear differences are evident. In the concrete element, which is located far outside in the construction, humidity levels of 80% occur in some cases. This is not harmful with concrete due to its resistance to mould. In a structure with external seagrass insulation without a vapour barrier, however, this would definitely have to be taken into account.

As already mentioned, the seagrass family Cymodoceaceae found in Seychelles’ waters is more closely related to Posidonia oceanica than Zostera marina. Since these two (Posidonia oceanica and Zostera marina) have very similar physical building values, it can be assumed that these are also true to reality, at least for the seagrass species of the Cymodoceaceae.

Seagrass meadows are critical components of India’s coastal ecosystems, providing essential ecosystem services such as carbon sequestration, coastal protection, and biodiversity support. The Indian coastline supports a diverse range of seagrass species, primarily found in Palk Bay and the Gulf of Mannar (Tamil Nadu), the Gulf of Kachchh (Gujarat), Chilika Lake (Odisha), and the Andaman, Nicobar, and Lakshadweep Islands.

Seagrasses in India belong to two major families: Cymodoceaceae and Hydrocharitaceae. Within these families, common genera include Cymodocea, Halodule, Halophila, and Enhalus, each adapted to specific environmental conditions.

• Family Cymodoceaceae

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  Cymodocea serrulata: One of the dominant species in Palk Bay and the Gulf of Mannar, it thrives in shallow, sandy substrates and is known for its high resilience to environmental stressors.

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  Cymodocea rotundata: Frequently coexisting with C. serrulata, this species is important for stabilizing sediment and providing habitat for marine fauna.

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  Halodule uninervis: A widespread species found in Chilika Lake, Gulf of Mannar, and the Andaman Islands, it plays a crucial role in nutrient cycling and primary production.

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  Halodule pinifolia: Found in the Lakshadweep Islands and shallow coastal areas, this species is highly adapted to varying salinity levels.

• Family Hydrocharitaceae

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  Halophila ovalis: One of the most widely distributed seagrasses in India, occurring in both intertidal and subtidal regions along the east and west coasts. It has high growth rates and colonization potential, making it a key species for seagrass restoration efforts.

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  Halophila beccarii: A vulnerable species found in mangrove-associated ecosystems on both coasts, it thrives in low-salinity, muddy habitats and is highly sensitive to anthropogenic pressures.

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  Enhalus acoroides: The largest seagrass species in India, primarily found in the Andaman and Nicobar Islands, it is important for providing habitat for dugongs and sea turtles.

Despite their ecological significance, seagrass ecosystems in India face multiple threats, including coastal development, pollution, and climate change. In regions such as the Gulf of Mannar and Andaman Islands, seagrass meadows are declining due to habitat disturbance and anthropogenic activities. Additionally, plastic contamination and inconsistent seagrass availability pose further challenges to its potential use as an insulation material.

Efforts to conserve seagrass ecosystems in India include marine protected areas, restoration projects, and improved monitoring. However, greater research, policy integration, and stakeholder engagement are needed to ensure the long-term sustainability of these critical coastal habitats.

4.2. Lack of Presence and Acceptance

The findings of the expert interviews reveal a limited awareness and low level of acceptance regarding the use of seagrass as an insulating material among relevant stakeholders. In the Seychelles, the response rate was particularly low, with only 12% of contacted individuals agreeing to participate in a short interview. This low return rate poses significant limitations in terms of the representativeness of the collected data and suggests that the perspectives captured may not adequately reflect the broader professional or societal views on the subject. In Auroville, discussions with local architects further confirmed that seagrass insulation has not yet been implemented in practice, highlighting the material’s peripheral status within current construction approaches. As corroborated by existing literature, seagrass continues to be predominantly perceived as coastal waste or, at best, as a component of the littoral nutrient cycle, rather than as a viable resource for sustainable building practices.

To address these limitations in future research, more robust engagement strategies are recommended. These include the early integration of local stakeholders through institutional partnerships, targeted outreach via professional associations, and the contextual framing of seagrass insulation in relation to pressing environmental and construction challenges. Additionally, employing snowball sampling techniques, offering participation incentives, and organizing stakeholder workshops may enhance accessibility, improve response rates, and contribute to a more representative and diverse dataset.

Despite the fact that seagrass beds have the highest value of ecosystem services of all coastal ecosystems, they receive little media coverage. This shows that seagrass is an unpopular topic. Some experts also commented on this issue, citing a lack of awareness as the reason for the low market share of seagrass insulation so far.

In 2022, this topic was also mentioned in a Seychelles-based study by the Blue Carbon Lab. Seagrasses and mangroves have also received very little attention in research to date. In the case of mangroves, there are already educational programs to raise awareness and appreciation. The study now calls for this focus for seagrasses as well. The study shows that seagrass is the least known marine ecosystem in Seychelles [2].

The results of the calculations on the structural suitability of seagrass show that insulation made of seagrass does not have an application problem, but an image problem. Accordingly, before an application can take place, the reputation of seagrass would first have to be improved, e.g., by highlighting its ecological value and physical building properties. It can be assumed that disproving inaccurate assumptions about seagrass (e.g., bad smell, mould, vermin, etc.) would also be a big step in the right direction. Only then can insulation with seagrass be developed further and find application.

4.3. Practical and Ecological Considerations for Seagrass Insulation Implementation

From both the literature research and the expert interviews, it can be deduced that the use of seagrass as an insulating material has many advantages and, in the end, generates negative CO₂ emissions.

There are major differences in the area of seagrass wash-up. Here, the statements of the two experts differ greatly. While B1 stated that seagrass is consistently washed up on the coasts, B2 was of the opinion that the loose seagrass drifts almost exclusively to the open sea and not to the coast. This shows that there is still a need for research on the frequency and quantity of seagrass washed up. If the seagrass does not drift to the coast, there will be significant changes in the collection and treatment process.

Among other things, it can be deduced from the many concerns of the experts about ecological burdens on the coastal ecosystem that the establishment of regulations and obligations and the obtaining of permits could be expedient before potential use. Some experts are of the opinion that seagrass should remain on the beach due to coastal protection measures. However, since many beaches have to be cleaned anyway, this argumentation—before a rethinking in the tourism sector has taken place—is less useful.

4.4. Possible Use of Seagrass Insulation

From the various process descriptions of the expert interviews, it emerged that the availability of an area close to where the seagrass is found is essential. In Seychelles, this could be a challenge as a large proportion of the land near the coast is either owned by the tourism industry, is under conservation, already has other uses, or has unsuitable topography (cliffs, steep walls). However, through interviews in the biology sector, it was found that most seagrass grows around the Outer Islands of Seychelles. Since tourism plays a smaller role there, it might be possible to find areas for storing seagrass there. In this case, however, it would still be interesting to check whether transporting the finished insulation material to the Inner Islands of the Seychelles makes sense from both an ecological and an economic point of view.

The feasibility of using seagrass insulation in Auroville and India presents both opportunities and challenges. As expert interviews indicate, the availability of storage and processing areas near seagrass accumulation sites is critical for its practical application. In India, particularly in Tamil Nadu, seagrass meadows in Palk Bay and the Gulf of Mannar provide a potential resource, but coastal land use conflicts, conservation regulations, and dense population make large-scale collection and processing difficult. Unlike Seychelles, where remote islands could serve as storage locations, India’s coastline is extensively used for fishing, tourism, and aquaculture, creating logistical and regulatory barriers. However, Auroville, with its focus on sustainable architecture, offers an ideal environment for pilot projects exploring seagrass insulation as a viable material for ecological construction.

Climate and weather conditions also play a significant role in processing and storing seagrass. While monsoon rains could help naturally rinse the material, the dry season poses challenges due to limited water availability, necessitating alternative low-water cleaning methods. High humidity levels in coastal India could also affect storage conditions, requiring efficient drying and compression techniques to prevent decomposition or mould growth. The high labour intensity of seagrass insulation could provide employment opportunities, but it also contrasts with the efficiency-driven nature of India’s construction industry, where prefabricated and synthetic materials dominate. To integrate seagrass insulation into the market, strong policy incentives and comparative cost–benefit analyses with conventional insulation options like EPS foam, glass wool, and coconut fibre insulation would be necessary.

Despite these challenges, seagrass insulation has promising applications in Indian architecture, particularly in naturally ventilated buildings. While some manufacturers recommend perimeter insulation, others highlight façade insulation as the most suitable use. In Auroville and other eco-conscious communities, seagrass could complement passive cooling strategies in double-roof systems or partition walls in sustainable housing developments. Additionally, integrating seagrass collection with beach maintenance initiatives in coastal tourism regions, such as Tamil Nadu, Kerala, and Goa, could create new business models that combine environmental restoration with material production. Further research and pilot projects are needed to assess seagrass insulation’s long-term performance, ensuring its feasibility as a sustainable alternative in India’s construction sector.

Rainfall is necessary to clean up the spread material on the surface. Depending on the monsoon season, this is more or less problematic. In times with less rainfall, the seagrass could not be sufficiently rained off. However, since the storage time of the seagrass in the open area is flexible, no difficulties are expected if the demand is moderate. The use of pure water for cleaning the seagrass would not make sense due to the already existing scarcity of this resource. Only a baler was mentioned as necessary process equipment. An agricultural vehicle is optional for collecting the seagrass. The necessary amount of seagrass per m² (in common use) is given as a range of 8–14 kg.

When it comes to the areas of application in the building, different seagrass manufacturers contradicted each other. While one spoke of suitability in the perimeter area, the other manufacturer recommended all areas of application except perimeter insulation. The simplest and safest option would probably be to use it as façade insulation, as this has been checked in the calculation and appears to be statically the most uncomplicated for large hotel complexes.

The high effort of installing seagrass insulation can be seen as both an opportunity and a challenge. On the one hand, the high time effort is unfavourable in today’s construction industry. On the other hand, this could have a positive effect on the Seychelles labour market, as it would employ more workers. Moreover, due to the manual processing, presumably no training or other exceptional knowledge would be required. Should the need for insulation ever arise in private buildings, the insulation can be installed oneself. There is too little information available on the economic aspects in relation to Seychelles’ framework conditions, which is why no assessment can be made on this at this point.

One expert’s idea in implementing a seagrass business for insulation production would be to negotiate a deal with hotels that want to keep the beaches “clean” for tourists. This would allow the expenses that the hotel has anyway to go towards the production of the insulation material. The mentioned possibility of additional expenses for the reforestation of seagrass meadows in case of uses of seagrass sounds likewise like an innovative combination of environmental protection and possibility of use despite the removal of a material from its ecosystem.

Collecting seagrass floating in the ocean could also be linked to tourism activities. For example, during a boat tour that is taking place anyway, there could be a kind of competition with prizes awarded for the largest amount of seagrass collected. However, in such a setting, the profitability for a company would be low. The collected seagrass could be used for pilot projects or for further research.

4.5. Seagrass Management and Sustainable Supply Chains as Ocean Conservation Opportunity

A structured seagrass collection, processing, and logistics network could serve as an effective model for both utilizing and protecting seagrass meadows, similar to how forestry and timber industries balance extraction with conservation. By establishing a supply chain for seagrass insulation, coastal communities could engage in regulated harvesting, ensuring that only naturally washed-up seagrass is collected while actively monitoring meadow health. This approach would integrate seagrass conservation with economic incentives, benefiting local communities and promoting long-term ecosystem management. Such a model would require collaboration between governmental agencies, conservation organizations, and industry stakeholders to establish guidelines for sustainable harvesting, quality control, and ecological monitoring. Periodic assessments of seagrass growth rates, seasonal fluctuations, and potential ecosystem impacts could help ensure environmental sustainability. Additionally, incorporating remote sensing and geospatial monitoring techniques could further support conservation efforts while streamlining the supply chain for insulation material production. If successfully implemented, this approach could transform seagrass from an underutilized coastal resource into a key component of sustainable building materials, aligning with circular economy principles. Furthermore, it could serve as a model for other blue carbon ecosystems, integrating coastal habitat conservation with green construction solutions.

5. Conclusions and Outlook

This study demonstrates that seagrass offers significant potential both as a critical ecosystem component and as an innovative sustainable insulation material. Prior research has already confirmed seagrass insulation’s durability, mechanical stability, and excellent natural moisture resistance, making it viable for long-term building applications [13,14,15,28,45]. Building upon this established knowledge, the current study uniquely evaluates its technical feasibility specifically for tropical climates, demonstrating through simulations that seagrass insulation effectively reduces overheating risks and maintains low mould-growth potential under persistently humid conditions. These findings align with previous temperate–climate studies, reinforcing seagrass insulation’s versatility across diverse climatic conditions while highlighting its untapped potential in tropical environments. Additionally, seagrass’s capacity to contribute to negative CO₂ emissions further strengthens its attractiveness for climate-positive construction practices. Integrating seagrass insulation into air-conditioned buildings in tropical regions could significantly enhance energy efficiency and cooling performance, offering both ecological and economic benefits.

Despite these advantages, this study does not provide a definitive conclusion regarding the large-scale feasibility of seagrass insulation in Seychelles’ hotel sector. The challenges related to land availability, regulatory barriers, and logistical constraints require further examination. However, the findings indicate that Auroville, India, presents a unique opportunity as an experimental hub for testing and refining seagrass insulation applications. With its established expertise in sustainable architecture, municipal support for eco-friendly building materials, and strong community engagement in innovative construction practices, Auroville is well-positioned to host pilot projects that validate the technical and practical viability of seagrass insulation.

The moisture protection analysis confirms that seagrass insulation performs well under tropical conditions, but further research is required to optimize its structural applications, economic feasibility, and long-term performance. Before broader adoption, several key measures should be taken:

• Improving public perception and awareness of seagrass as a valuable building material through educational campaigns, industry outreach, and integration into construction guidelines.
• Expanding the study scope to other tropical regions, conducting a systematic stakeholder consultation process, and refining the research methodology for higher significance and applicability.
• Investigating the physical performance of seagrass insulation by analysing its thermal conductivity, moisture regulation, fire resistance, and long-term durability in tropical climates. Developing a dynamic moisture protection model to assess insulation behaviour under varying climatic conditions.
• Assessing local seagrass availability by conducting ecological impact studies and collaborating with policymakers to determine sustainable harvesting guidelines.

The subsequent outlook statements summarize broader implications arising logically from our findings, adhering to scientific standards by providing context and future research directions: A particularly promising direction is the integration of seagrass insulation into circular economy models. Establishing a structured collection, processing, and logistics framework could not only enable consistent material supply but also support marine ecosystem conservation, similar to sustainable forestry practices. Further collaboration with government agencies, conservation organizations, and research institutions—such as the Auroville Earth Institute—could help advance seagrass-based insulation solutions through innovative building prototypes. Given Auroville’s high temperatures and focus on ecological living, seagrass insulation could play a crucial role in reducing energy consumption for cooling while creating employment opportunities for local craftsmen and builders. If successful, this pilot initiative could serve as a scalable model for integrating bio-based insulation into tropical construction, bridging sustainability goals with practical implementation. Future research and cross-sector collaborations will be essential in transforming seagrass from an underutilized marine resource into a viable, climate-positive building material for global applications.