Circular Economy in Rammed Earth Construction: A Life-Cycle Case Study on Demolition and Reuse Strategies of an Experimental Building in Pasłęk, Poland

Abstract

This study aims to evaluate the potential of circular economy principles in earth-based construction using an experimental rammed earth building located in Pasłęk, Poland as a case study. The research focuses on end-of-life scenarios for earth materials, with particular emphasis on rammed earth, adobe, and compressed earth blocks stabilized with Portland cement. A scenario-based life-cycle assessment (LCA) was conducted to compare alternative demolition and reuse strategies, including manual and mechanical deconstruction, as well as on-site and off-site material reuse. Greenhouse gas emissions associated with demolition (Module C1) and transport (Module C2) were estimated for each scenario. The results indicate that manual deconstruction combined with local, on-site reuse leads to the lowest carbon footprint, whereas off-site reuse involving long-distance transport significantly increases greenhouse gas emissions. In addition, qualitative reuse pathways were identified for wood, glass, ceramics, and insulation materials. The study reveals a lack of standardized technical procedures for the recovery and reuse of stabilized earthen materials after demolition and highlights the importance of integrating end-of-life planning into the early design phase using digital tools such as material passports and BIM. The findings demonstrate that properly designed rammed earth systems can provide a viable low-tech solution for reducing construction waste and supporting circular material flows in the built environment.

1. Introduction

Motivation

As indicated by the European Environment Agency [1], construction and demolition waste constitutes the largest waste stream in the European Union. Although relatively high recovery rates are reported, these are predominantly achieved through low-value applications such as backfilling excavations and the use of demolition-derived aggregates in road base construction [1]. While some EU countries have implemented more advanced recycling and reuse strategies, a substantial proportion of construction materials is still landfilled globally. At the same time, the construction sector remains a major contributor to natural resource consumption and greenhouse gas emissions, underscoring the need for more effective end-of-life strategies.

In this context, demolition and material reuse strategies are of particular importance for earth-based construction systems. Such systems rely on local, low-processed raw materials that may align well with circular economy principles. Unfired earth materials, under suitable conditions, can potentially be recovered and reused, offering opportunities to reduce resource depletion and emissions associated with both material production and disposal.

Designing buildings with the future use of materials in mind is a central aspect of sustainable architectural practice. Within circular design approaches, buildings are increasingly understood as temporary repositories of resources rather than fixed end products. While current strategies often emphasize design-for-disassembly and material reuse, comparatively little attention has been given to demolition planning and waste-to-resource management for monolithic and masonry construction systems, particularly those based on earth materials and containing stabilizing additives.

This article investigates how rammed earth construction systems can support circular economy strategies through material recovery and reuse at the end-of-life stage. Using an experimental building in Pasłęk, Poland as a case study, the research evaluates selected demolition and reuse scenarios for earthen components based on life-cycle assessment (LCA) and identifies practical pathways for reducing embodied carbon. In doing so, the study addresses a methodological gap related to the deconstruction and recycling of stabilized earth-based materials.

2. Literature Review

2.1. Embodied Carbon and Material-Related Emissions in Construction

Construction accounts for a significant proportion of greenhouse gas emissions—it is estimated that the construction sector generates around 37–39% of global greenhouse gas emissions [2,3], including operational emissions (e.g., related to heating, hot water, or cooling of buildings) and embodied carbon, i.e., emissions related to the production of materials, their transport, assembly, and demolition. Concrete, steel, and aluminum play a significant role here, as their production is associated with high energy consumption and CO₂ emissions [2]. In comparison, wood and recycled materials (e.g., chipboard, glass mineral wool), as well as reused products, have a significantly lower carbon footprint and can play an important role in decarbonization strategies for the construction industry [4,5,6].

In this context, designing with a view to minimizing emissions throughout the entire life-cycle of a building, including at the end of its life, is becoming increasingly important. A paradigm shift in design means not only choosing low-emission materials, but also taking into account dismantling, reuse, and recycling [4]. Research indicates that errors made during the implementation stage are also a significant source of emissions and waste. According to an analysis [7], up to 30% of construction waste results from design errors, improper handling of materials, and residues from site preparation. This waste not only burdens the environment but also increases construction costs by up to 30% of material costs [7].

Against this broader background of embodied impacts and waste generation, earth-based construction is often discussed as a low-emission alternative; however, reported emission values show considerable variability across the literature sources and databases.

Greenhouse gas emissions associated with earth technologies vary considerably between the literature sources and databases. These differences are due to different production methods, composition of raw materials, transport distances, and types of stabilizing additives. In addition, authors often use different functional units (kg, m², m³), which makes direct comparisons difficult. This section summarizes reported embodied emissions for adobe and rammed earth technologies, and all results are converted to the unit kgCO₂e/m³, per cubic meter of wall, to ensure comparability.

A study by Christoforou et al. (2016) [8] calculated the embodied carbon footprint for adobe bricks made from clay and straw. For locally produced bricks (local clay and transported straw), embodied emissions were 0.00176 kgCO₂e/kg, which at a density of 1544 kg/m³ corresponds to 2.72 kgCO₂e/m³. For industrially produced bricks (transport of clay and straw), these emissions increased to 0.0129 kgCO₂e/kg, or 19.91 kgCO₂e/m³ [8]. These results indicate that reducing transportation and using local raw materials significantly reduce greenhouse gas emissions.

The ÖKOBAUDAT database shows that, for adobe bricks with a density of 1200 kg/m³ (industrial production), embodied emissions are 98.1 kgCO₂e/m³. The difference between the previous values may be due to more energy-intensive production processes and longer transportation.

For rammed earth technology, ÖKOBAUDAT reports an average value of 9.96 kgCO₂e/m³ at a density of 2000 kg/m³. This material can be made of clay, sand, straw, and other additives. In southern Germany, where the clay contains larger fractions, additives are often unnecessary. The process involves tamping successive layers with a pneumatic rammer, without the addition of cement [9].

Ávila, Puertas, and Gallego (2022) [10] indicate that embodied emissions for unstabilized rammed earth (URE) walls are 3–9 kgCO₂e/m³. Stabilization with cement (SRE) at 2.5% increases emissions to 42 kgCO₂e/m³, and at 5% to 86 kgCO₂e/m³. Further increasing the cement content (7.5–10%) increases the carbon footprint to 131–179 kgCO₂e/m³ [10].

The study by Arrigoni et al. (2017) [11] analyzed soil mixtures, only some of which met the requirements of HB 195 (minimum 2.0 MPa) and were suitable for construction. One of the mixtures without a stabilizer (Mix 6) failed the erosion test. Compressive strength does not always correlate with durability—well compacted mixes can be durable despite low UCS. Mixes with cement (such as Mix 1) had the greatest environmental impact. Replacing cement with fly ash (FA) and/or Calcium Carbide Residue (CCR) reduced emissions by 50–85%. Using local demolition aggregates further improved environmental performance. Cement-free mixtures (e.g., Mix 5) had significantly lower energy consumption and emissions [11].

Studies indicate that biomass ash and natural stabilizers (e.g., chitosan, carrageenan, potato starch, sisal fibers) improve mechanical properties and resistance to external agents [12]. Ramezannia [13] showed that replacing 2% of cement with natural fibers (e.g., Australian spinifex) reduces the carbon footprint by 20–43% while improving thermal insulation.

It should be noted that, although the literature reports promising results for the use of biomass ash and natural fibers as stabilizing agents in earth-based materials, these approaches are associated with additional technical uncertainties. Natural fibers may be susceptible to biological degradation, depending on moisture conditions and pH, which requires careful material selection, detailing, and durability validation. The use of industrial by-products such as fly ash may introduce variability in chemical composition and potential contamination risks, making quality control and environmental assessment necessary. Furthermore, alkaline activation processes, while effective in enhancing binding properties, may affect fiber compatibility and long-term chemical stability. These aspects indicate that such stabilizers should be treated as research-driven solutions rather than universally applicable construction practices.

Cristelo [14] proposed alkaline activation of fly ash (FA) as an alternative to cement. Langmaack [15] found that the highest emissions are associated with grinding and transportation. Locally sourced clay can significantly reduce energy consumption. Burnt bricks have a carbon footprint of 560 kgCO₂e/m³, while raw bricks have only 95 kgCO₂e/m³.

The addition of lime or cement significantly increases emissions due to emissions from clinker production. Emissions also depend on the type of cement—CEM III/B has a lower carbon footprint than CEM I due to its content of blast furnace ash instead of clinker.

Ajabi Naeini [16] showed that replacing 50% of Portland cement with paper industry ash yielded a material with lower strength, but was still resistant to freeze–thaw cycles. The addition of 15% calcium bentonite significantly improved mechanical performance and durability.

Experiments with cement containing vegetable ash additives to reduce emissions have been conducted [17]. Such cement may be a greener alternative to cementitious stabilizers for earth-based construction.

According to [18], stabilization with Portland cement results in emissions of approximately 131 kgCO₂e/m³, while hydraulic lime results in emissions of 94 kgCO₂e/m³. Alternative additives (e.g., cow manure, straw fibers, casein, linseed oil, milk protein) have very low emissions, often below 30 or even 10 kgCO₂e/m³.

A summary of the embodied greenhouse gas emissions for individual products is shown in

Table 1. Comparison of the embodied emissions of selected earth-based technologies.

Technology	Embodied Carbon (kgCO2e/m3)	Source
Adobe bricks (on-site)	2.72	[8]
Adobe bricks (industrial)	19.91	[8]
Adobe bricks	95.00	[15]
Adobe bricks (industrial)	98.10	[19]
Unstabilized Rammed Earth	9.96	[9]
Unstabilized Rammed Earth	3.00	[10]
Unstabilized Rammed Earth	9.00	[10]
Rammed Earth + 2.5% cement	42.00	[10]
Rammed Earth + 5% cement	86.00	[10]
Rammed Earth + 7.5–8% cement	131.00	[10]
Rammed Earth + 10% cement	179.00	[10]
Stabilized Rammed Earth with Portland cement	131.00	[18]
Stabilized Rammed Earth with hydraulic lime	94.00	[18]
Rammed Earth with natural additives	10.00	[18]
Rammed Earth with natural additives	30.00	[18]
Sand-lime bricks	226.80	[20]
Concrete bricks	229.00	[15]
Fired clay bricks	312.00	[21]
Fired clay bricks	560.00	[15]

.

Based on the studies mentioned above, it can be concluded that the carbon footprint of earth technologies depends mainly on the following:

• the type and amount of stabilizer used;
• the distance over which raw materials and products are transported;
• the production method and degree of processing.

The lowest emissions are achieved when building on-site, using local raw materials and avoiding cement. In extreme cases, stabilized earth structures may exhibit a carbon footprint similar to that of conventional concrete. The choice of stabilizers also influences the end-of-life recyclability of the material.

2.2. Demolition, Waste Streams, and Circular Reuse Strategies

Nowadays, the key role in the construction industry is played by circular economy (CE) and sustainability. They are becoming a political and economic priority for global urban development [22]. Many recent studies have underlined the role of CE in the construction and built environment sector. Construction-focused studies and strategies of reuse and material recovery are starting to become key drivers of circularity [23,24]. According to Krajowska and Siewczyńska [25], the reuse of materials is still not common practice. Demolition-related end-of-life activities generate over half of construction sector waste [26]. Waste management in architecture and construction are still insufficiently integrated into circular design strategies. Current strategies focus on design for the disassembly of new buildings using modular technologies and frame structures, step-by-step demolition, and the creation of material banks to reuse building materials and elements after demolition. These approaches remain limited in European countries because of a lack of city strategies for circular building and environment and high costs of such materials. Waste which can become a resource is available in all cities. Urban mining is used to identify “invisible” sources, which is the process of reclaiming compounds and elements from wasted or at least undesired products or buildings which still have highly valuable materials to be reused or recycled [27]. Building from waste could be one of the solutions in the sustainable development idea. Zero waste solutions can lead to minimizing material consumption. In this case, city metabolism and the architectural metabolism of materials will play an important role and should be included in the architectural design process and scenarios of development and management of urban areas, including the knowledge of circular design and development. Based on this, selective demolition solutions and non-destructive testing of materials will increase. Such solutions can concentrate on finding the method for the possibilities of mapping used materials and components as a possible resource, not to lead to generate waste. Waste generated in construction and demolition is among the largest waste streams in the world and accounts for a significant portion of global solid waste. Construction and demolition waste (CDW) is one of the largest waste streams globally, accounting for an estimated 30–40% of total solid waste [28]. Such a way of thinking is an alternative for a new way of designing for disassembly.

Design solutions which take into account circular design and the possible of use of as many materials as possible after the demolition of a building, including the design-for-disassembly, are visible in the example of Circl—the circular pavilion in Amsterdam’s Zuidas District. The building was designed for ABN AMRO by Pi de Bruijn, Hans Hammink de Architekten Cie, and Donkergroen i.s.m. de Architekten Cie (landscape designer) in cooperation with TU Delft (circularity advisor), BAM Bouw & Techniek (constructor, structural engineer, installation advisor), and DGMR (building physics advisor) as a temporary building in which sustainable construction technologies were used. In the end, 80% of the used materials and building elements could be moved and reused in another location. The structure of the building was designed as a timber beam and column structure, made with locally sourced larch wood, with disassembling joints to make as little impact on the environment as possible. This strategy also include aluminum panels and a curtain wall system used on facades. As a thermal and acoustic isolation, denim isolation was used on ceilings produced from jeans and cotton clothes given by employees and partners of the bank. The building was designed as a three-story (with basement) pavilion with a flat roof. On the elevations, PV modules were used to produce energy, and a green façade was used to regulate the microclimate in the building’s surroundings and to create a green, quiet space with a comfortable atmosphere in an urban area. In the building, a recycled hardwood parquet floor was reused from different donors, as well as used windows to create partition walls in the basement area.

During design and management, a digital twin was created in which all data about materials and their impact on the environment were included based on a material passport.

The construction waste stream is not homogeneous. It consists of several major categories, each posing specific environmental and logistical challenges. Among them, demolition waste constitutes by far the largest share by volume. Over 90% of total construction and demolition waste (CDW) in the US originates from the dismantling phase of existing buildings, while less than 10% comes from new construction [29]. This highlights the importance of considering waste management strategies already at the design stage, particularly in relation to end-of-life scenarios.

Traditional demolition processes often generate mixed waste (rubble, wood, metals, plastics, glass), which complicates recycling and reuse. This underlines the potential benefits of implementing design-for-disassembly principles and selective dismantling, allowing for better sorting and material recovery. Many of these waste materials, such as concrete, bricks, ceramic elements, and soil, can be crushed and reused as secondary aggregates. Metals, due to their market value, are already effectively recovered. Wood and plastic waste, however, still pose challenges related to contamination and polymer diversity.

In this context, earth-based construction systems offer promising opportunities for circular material flows. Soil and earth components are among the most significant mineral fractions in the CDW stream and can be reused under proper technical assessment. Some projects already incorporate prefabricated rammed earth panels that can be disassembled and reused. This strategy aligns with broader circular economy goals, as noted by [30], who emphasized that earth materials from demolition or excavation, if geotechnically suitable, can be reintegrated into construction.

Existing research also explores incorporating recycled materials into new earthen structures. For instance, Ref. [31] proposed using recycled concrete aggregate in stabilized rammed earth mixtures to enhance structural performance. Such practices contribute not only to waste reduction but also to the development of sustainable construction systems.

Although current examples remain limited, they indicate practical pathways for integrating waste reuse into both construction processes and architectural design. The case of dismantled historic rammed earth buildings further illustrates the feasibility of reusing earthen components [32]. These precedents, combined with the development of deconstructible systems and innovative materials, open new perspectives for including waste management as an integral part of architectural and technical planning.

Another area of growing interest involves expanded polystyrene (EPS) waste. Due to its low density and high volume, EPS is difficult to recycle, and much of it ends up in landfills. However, methods have been developed to reuse EPS waste, including its dissolution in solvents such as limonene for easier transport and recovery [33,34]. EPS can also be reused as an aggregate in lightweight, thermal-insulating mortars. A waterproofing preparation based on dissolved polystyrene was also developed by researchers at Warsaw University of Technology [35]. These innovations demonstrate how material recovery can be technologically integrated into circular design strategies.

2.3. Research Gap and Methodological Limitations

Despite growing interest in sustainable construction practices, comprehensive strategies for managing construction waste during the demolition of monolithic and masonry structures remain underdeveloped. Existing approaches primarily emphasize design-for-disassembly and material reuse; however, they do not sufficiently address the methodological aspects of demolition planning of the integration of waste-to-resource management within an interdisciplinary framework combining architecture and construction engineering.

Current trends in sustainable development primarily emphasize the creation of design methodologies for new buildings, such as design-for-disassembly, as it enables a more efficient use of embedded materials after their end-of-life, especially in a certain product, and it could be a new business model [36]. However, an equally critical challenge lies in developing systematic approaches for the reuse of materials generated during the demolition of existing buildings. Potential demolition waste from existing buildings is recognized as a valuable material bank which can be considered for future constructions [37]. Establishing scenarios for potential material reuse represents a fundamental step toward advancing circular design principles, as it enables the integration of recovered resources into new construction processes. Future buildings’ design and construction use should encourage the reuse of materials [38].

A critical research gap concerns the end-of-life recovery of earth-based materials, such as a rammed earth walls and adobe bricks. Although preliminary studies and isolated examples indicate potential reuse pathways, there is a lack of standardized, scalable methodologies for reclaiming monolithic rammed earth elements and other types of materials after demolition. This deficiency is compounded by the absence of design guidelines that incorporate considerations for disassembly, material recovery, and reintegration into circular material flows. Categorizing and developing demolition scenarios and potential reuse options can be an important part of a design methodology that takes into account the use of recycled materials and construction waste during the revitalization or repurposing and demolition of buildings in accordance with the concept of inward development.

The originality of this research lies in its focus on developing technical and methodological frameworks that enable the systematic recovery, transformation, and reuse of earth-based materials. By establishing practical guidelines and adaptable strategies, this work aims to facilitate their integration into new construction systems and material cycles. These outcomes are expected to advance circular construction practices in existing buildings and revitalization, reduce environmental impacts, and provide actionable solutions for industry stakeholders to develop new construction products based on using demolition waste, thereby bridging a critical gap between theoretical sustainability concepts and their real-world implementation. Further research will include integrating construction demolition waste into new construction systems or material cycles.

3. Materials and Methods

The assessment was conducted to support decision-making regarding environmentally optimal demolition strategies and circular reuse pathways for rammed earth and related earth technologies. The life-cycle assessment (LCA) was performed in accordance with the principles of ISO 14040/14044 [39,40] and EN 15978 [41], with the aim of quantifying greenhouse gas emissions associated exclusively with the end-of-life phase of earth-based construction systems applied in the experimental building in Pasłęk, Poland. The analytical scope was therefore limited to Modules C1 (deconstruction and demolition) and C2 (transport of recovered materials), while further processing, final disposal (C3–C4), and potential benefits beyond the system boundary (Module D) were deliberately excluded from the assessment.

The functional unit of the study was defined as 1 m³ of earth wall material at the end-of-life stage, allowing for the comparison of alternative demolition and reuse scenarios on a material basis. In addition, the total volume of earth-based walls in the building, amounting to 72.15 m³, was used as a secondary functional reference for building-scale interpretation of results.

Input data to the analysis were taken from the building permit design of the experimental building in Pasłęk in Poland. All additional data were taken from different previous publications which presented measurements of building microclimate conditions [42,43], tests of strength of earth blocks [44], construction phases, and design solutions [45]. In cases of missing data, interviews with designers were conducted.

The possibilities for the reuse of materials after demolition were investigated using heuristic research [46] conducted in the manner of scenario creation (similar to a part of the SWOT method), which was used to describe opportunities and their impact on the life-cycle of materials used during building construction. A variety of scenarios were designed based on the research of possible use after demolition found in research articles and in architectural examples. Alternative end-of-life scenarios (Modules C1–C2) were developed for each of the earth technologies used in the building, taking into account both the method of demolition and the potential routes for further use of the recovered material. Manual and mechanical techniques were considered, as well as varying transport distances, depending on the assumed reuse strategy.

Assumptions were made for the calculation of greenhouse gas emissions associated with the C1–C2 end-of-life modules. For each scenario, CO₂-equivalent (GWP) emissions attributed to the demolition and transportation phases were estimated.

For the purpose of calculating the carbon footprint for a unit volume of 1 m³ of wall and for the total volume of all walls made with earth technology, the following assumptions were made:

• Manual demolition is assumed to generate no direct fossil-fuel-related emissions from demolition machinery; minor indirect emissions are acknowledged but considered negligible within the scope of this screening-level assessment.
• For mechanical demolition, an emission factor based on the ÖKOBAUDAT database for rammed earth walls with a density of 2000 kg/m³ was assumed to be 0.7134 kgCO₂e/m³ in the C1 module. The product description in the ÖKOBAUDAT database states “During the disposal phase, manual dismantling is taken into account in Module C1 for plasters, mortar and construction boards made of clay, and a mechanical dismantling for staple walls and clay masonry.”
• The processes of grinding and granulation were considered part of the life-cycle of the new product (Modules A1–A3) and excluded from the system boundaries of the analyzed Modules C1–C2.
• Transport of the material is carried out using a 20-ton self-unloading vehicle. Combustion was assumed at 35 L/100 km for an unloaded vehicle and 45 L/100 km for a loaded vehicle, based on empirical data of users website forum www.wagaciezka.com.
• The emission factor for diesel fuel is 2.68 kgCO₂/L, according to the guidelines [47] (categories 1.A.3.b.i–iv).
• The volumetric density of the walls was assumed based on ÖKOBAUDAT data—2000 kg/m³.
• The total volume of earth material to be demolished is 72.15 m³, of which, after accounting for 10% material losses, 64.93 m³ remains, equivalent to about 129.9 tons.
• For the transportation of the material, the number of trips of a 20-ton vehicle was estimated at 7.
• The excavation rehabilitation work is carried out by a backhoe-pusher with a bucket capacity of 0.15 m³. The total operating time of the machine was estimated at 16.5 h, with an assumed fuel consumption of 6 L/h and emissions of 2.68 kgCO₂/L [47] (categories 1.A.3.b.i–iv).

The results of the calculations are presented in detail later in the “Scenarios” Section, with the end-of-life of earth technologies used in the experimental building according to LCA. No dedicated LCA software was used in this study. The life-cycle assessment was performed using a calculation-based approach implemented in spreadsheet software (MS Excel). Input data were derived from the experimental building documentation, the literature sources, and emission factors from established databases (in particular ÖKOBAUDAT), and the calculations were carried out manually in accordance with ISO 14040/14044 and EN 15978 principles (data specified in Section 3). The research was not intended to deliver a full building-level LCA, but rather a targeted, scenario-based assessment of the end-of-life stage of earth-based construction systems.

The main research questions addressed in the study are as follows:

• How do different demolition strategies (manual versus mechanical) influence greenhouse gas emissions associated with the end-of-life stage of rammed earth and related earth-based construction systems?
• How does the assumed transport distance for recovered earth materials affect the carbon footprint of end-of-life scenarios?
• Which end-of-life scenarios for earth-based materials offer the lowest embodied carbon emissions while supporting circular economy principles and material reuse?

3.1. Description of the Research Subject

An experimental building designed and constructed by researchers at the Faculty of Architecture at Warsaw University of Technology was chosen as a research subject, to test different earth technologies in the climate of Central Europe. The design and construction of an experimental building in Pasłęk in Poland was supported by the grant founded by the Ministry of Science and Higher Education of Poland in 2005. The construction started in 2006 and finished in 2008.

3.1.1. Design Concept of Experimental Building in Pasłęk in Poland

The main goal of the design of the experimental building in Pasłęk was to demonstrate the possibilities of using different types of earth construction technologies as a part of a pro-environmental strategy of designing buildings from waste (earth excavated on the construction site) and the presentation of different passive design solutions for enhancing buildings’ energy efficiency. The building’s location was properly selected in the Ecological Park in Pasłęk.

The project was carried out thanks to a grant awarded to the design team leader from the Faculty of Architecture, Warsaw University of Technology, supervised by prof. Teresa Kelm. The team included, among others, PhD Arch. Jerzy Górski, MSc Arch. Marek Kołłątaj, and PhD Dorota Długosz-Nowicka (for technological research). Structural design for the building permit was prepared by PhD Ireneusz Cała.

The building was designed to optimize shape and orientation for favorable energy conditions. Two longer facades face north and south. The northern facade has no windows to minimize heat loss, while the southern facade includes extensive glazing and a greenhouse to accumulate solar energy. The extended northern wall protects against prevailing winds [44]. The roof is extensive and covered with local vegetation.

The main space also connects to a utility area (kitchenette, toilet) on the west side. The building’s footprint is 105 m², usable area 75.5 m², and volume 250 m³ [45]. The exterior walls were designed using rammed earth, inspired by natural, organic forms. The single-storey building was placed in the southeastern corner of the site and features a green mono-pitched roof sloping north (Figure 1).

The building was designed to be energy-efficient in construction and operation. The rammed earth walls are placed on a high waterproof plinth and protected from rain by wide eaves. The southern glazed veranda collects solar energy for passive heating.

Earth technologies were used as the main ecological and structural solution. To test the material under the harsh northern Polish climate, cement was added to stabilize the earth mixture. Another goal was to expose the raw surface of the rammed earth as an example of unconventional construction.

The structural layer of the external walls was designed as a visible rammed earth layer, allowing for research into climatic impacts (e.g., air humidity, vapor diffusion, dew point).

The building includes plumbing, cold and hot water systems, and electricity. Heat is provided by a cast-iron wood stove, with electric outlets for optional heaters. Water is heated by an electric storage tank.

The goal was to achieve a good indoor microclimate. The accumulating walls and southern greenhouse were positioned to maximize solar gains and reduce overheating.

Earth wall surfaces adapt to humidity changes, absorbing and releasing moisture. Wide eaves prevent rain contact, exposing walls only to air humidity. This natural regulation, along with ventilation, protects against frost. Seasonal observations confirmed the durability of earth walls. Rain chains were used instead of downpipes.

A key element of the energy strategy was the glazed southern veranda. Passive solar gain depended on glazing size and low-emission double glazing. The wall between the veranda and the main room was left uninsulated to allow heat accumulation and transfer.

3.1.2. Building Technologies and Materials Used in Experimental Building

The building was designed to perform different construction technologies based on the use of earth solutions based on different building units and off-site and on-site solutions. Load bearing walls were constructed as a rammed earth technology. Rammed earth technology was used for the structural and exterior walls, utilizing earth from the excavations on the plot (reducing transportation costs of building materials).

A compressed mixture of earth excavated on the construction site to make foundations was mixed with sand (55–75%), loam (10–28%), and clay (15–18%) stabilized with Portland cement (8%). Thermal Efficiency Optimization for the earth mixture was optimal at the level of 14.5% [44] (Figure 2).

Interior insulation includes straw–clay blocks and mineral wool, while partition walls were made of pressed earth blocks, air-dried near the site and left unfinished. Most exterior walls were designed as three-layer systems: a structural rammed earth core, mineral wool insulation, and an inner layer of clay–straw blocks, finished with earth plaster. Though cellulose insulation was originally planned, it was replaced with mineral wool due to budget constraints.

Lintels were constructed in timber frame technology and insulated. Windows and doors are wooden, with zinc-titanium flashings and sills. Kitchen and bathroom walls are finished with ceramic tiles. The floors, built on a concrete slab over compacted sand, include thermal and moisture insulation, with stone or ceramic tile finishes serving as thermal mass. Although clinker tiles were initially planned, stone was used to create a unified esthetic.

The roof is a single-pitched timber structure insulated with mineral wool, designed for an extensive green roof with local vegetation. Its multilayer build includes bitumen membranes, geotextile, and a ventilated air gap. The eaves extend to protect the rammed earth walls from direct rain. Rainwater is collected from the roof via gutters and chain downspouts, and directed into soak away pits to support groundwater recharge.

4. Results and Discussion of Analysis of Experimental Building Constructed in Rammed Earth Technologies in Pasłęk in Poland in the Case of Development of Scenarios for the Reuse of Materials After Demolition

Buildings constructed using rammed earth technology are often seen as an environmentally friendly solution—the main building block of their walls is natural rammed earth (soil), which significantly reduces the carbon footprint and the amount of recycled materials. However, even such structures are not fully “waste-free,” as they contain other, more conventional building components in addition to extremely large rammed earth walls.

In any construction site in which reused materials will be used, any material sample must be tested and analyzed according to the legal regulations, technical standards, and environmental requirements dedicated to any region or country. Mostly, they are concerned about material classification, contamination thresholds, geotechnical sustainability, and intended application. Any material used should be implemented into construction under compliance with building codes, soil quality standards, and environmental protection regulations. Regularity constraints may also arise from planning regulations, construction norms, and quality control procedures that limit where and how reused earth materials can be applied.

4.1. Identification of Materials Used in Construction of the Experimental Building in Pasłęk

Construction materials and elements used in the experimental building based on the technical documentation of construction and building permit design were identified in the

Table 2. Identification of materials used during construction.

No.	Material Group	Building Unit	Specification
A	Cement and concrete
A.1	Reinforcement concrete	Foundation	B20, A-OStOS rods Ø12, horizontal rods Ø6
		Ring beam	nd
		Ramp	nd
		External stairs	nd
A.2	Concrete blocks	Plinth wall
A.3	Mortar	Plinth wall
A.4	Cement screed	Slab on the grade	6 cm, 10 cm
A.5	Light concrete	Slab on the grade	15 cm
B	Earth
B.1	Rammed earth	External walls (one and three layers)	40 cm sand, loam, clay, earth and Portland cement mix
B.2	Pressed earth blocks	Partition walls	nd if stabilized
B.3	Clay and straw blocks	Internal layer of three-layered wall	12 cm, clay and straw mix
B.4	Earth substrate	Green roof
B.5	Earth plaster	Interior plater	Clay, straw, sand
C	Wood
C.1	Structural timber	Rafters	14 × 28 cm spacing 90 cm
C.2		Purlin	14 × 28 cm
C.3		Wall plates	14 × 14 cm
C.4		Timber frame	nd
C.5		Lintels	nd
C.6	Timber cladding	Internal and external finishing	Planed boards, matt varnish
C.7	Technical wood	Boarding on the flat roof	2.5 cm
		Wood boards	Impregnated
C.8	Building elements	Wood sills
C.9		Windows	Wood frame with glazing
C.10		Interior doors	Wood frame with glazing
C.11		Entrance doors	Wood frame and wood finish
C.12		Veranda	Wood frame with glazing
D	Glass
D.1	Double glazing	Windows	nd
D.2		Veranda doors	nd
D.3		Curtain wall on veranda	nd
E	Stone
E.1	Pebbles stone	Plinth
E.2	Cut stone	Floor
		Ramp
E.3	Mineral wool	Wall insulation	8 cm
		Timber frame wall with lintels	18 cm
		Roof insulation	22 cm
F	Metal
F.1	Struts	Roof structure in veranda	Steel
F.2	Chains	Down pipes	nd
F.3	Flashing	Roof and external sills	Zinc-titanium plate
		Gutter and flashing	Coated steel
F.4	Ventilation elements	Pipes	Zinc-titanium plate
F.5		Chimney cover	Zinc-titanium plate
F.6	Angle bar	Green roof	Perforated aluminum
G	Ceramic
G.1	Tiles	Walls in kitchen and toilet
G.2		Stoneware in toilet
G.3	Brick	Chimney
H	Others
H.1	Polystyrene foam	Slab on the grade	5 cm
H.2	Asphalt saturated felt	Foundation	Glued
		Green roof	Welded
H.3	VCL	Frame structure, roof
H.4	Wind barrier foil	Frame structure
H.5	Geomembrane	Green roof
D	Glass
D.1	Double glazing	Windows	nd
D.2		Veranda doors	nd
D.3		Curtain wall	nd
E	Stone
E.1	Pebbles stone	Plinth
E.2	Cut stone	Floor
		Ramp
E.3	Mineral wool	Wall	8 cm
		Frame walls	18 cm
		Roof	22 cm
F	Metal
F.1	Struts	Roof structure	Steel
F.2	Chains	Down pipes	nd
F.3	Flashing	Roof and external sills	Zinc-titanium plate
		Gutter and flashing	Coated steel
F.4	Ventilation elements	Pipes	Zinc-titanium plate
F.5		Chimney cover	Zinc-titanium plate
F.6	Angle bar	Green roof	Perforated aluminum
G	Ceramic
G.1	Tiles	Walls in kitchen, toilet
G.2		Stoneware in toilet
G.3	Brick	Chimney
H	Others
H.1	Polystyrene foam	Slab on the grade	5 cm
H.2	Asphalt saturated felt	Foundation	Glued
		Green roof	Welded
H.3	VCL	Frame structure, roof
H.4	Wind barrier foil	Frame structure
H.5	Geomembrane	Green roof

. In the building, eight different groups of materials were identified.

4.2. Scenarios for Reuse and Demolition

Possible scenarios for the potential use of materials and building elements used during building construction were divided into groups based on material type and similar process of disassembly, testing, recycling, and reuse.

The following scenarios represent the basis for the quantitative end-of-life analysis presented in Section 4.3.

4.2.1. Scenarios for Reinforced Concrete and Concrete Components

Reinforcement concrete and concrete slabs:

• crushed and reused as aggregate for new concrete production (recycled aggregate concrete);
• used as aggregate in earthworks for embankment or subgrade stabilization;
• used as additive in rammed earth construction for structural stabilization;
• used as filler or base layer in new construction (e.g., road foundations);
• crushed and reused for production of rubble concrete brick;
• crushed and used in gabion structures.

Concrete blocks:

• reused as concrete blocks after careful demolition and mortar removal;
• crushed and used in gabion structures;
• crushed and reused as aggregate for new concrete production (recycled aggregate concrete).

Steel rebar from crushed reinforced concrete:

• collected and recycled as scrap metal in steel mills;
• reused after mechanical straightening (if undamaged and permitted by standards);
• downcycled into low-grade steel products (e.g., fencing, mesh, small hardware).

4.2.2. Scenarios for Earth Components

To ensure the safe reintegration of recovered earth-based materials into the construction cycle or the natural environment, a multidisciplinary assessment is required. This assessment should combine geotechnical testing, material characterization, and environmental chemistry analyses in order to verify mechanical performance, durability, and environmental neutrality prior to reuse.

Rammed earth and pressed earth blocks:

• due to the presence of stabilizers, they should be crushed and reused as an aggregate in the production of new earth components, which should be possible based on the results of the use of demolition waste in different research examples for the production of compressed earth blocks [48,49];
• if allowed by local regulations and the material is environmentally neutral, it may be returned to the ground, for example, to backfill the excavation left after building removal;
• if not suitable for reuse in construction, it can be used as fill material or sub-base in road construction and earth embankments.

Clay and straw blocks (internal layer of three-layered wall) finished with earth plaster:

• because no additives were added to the mixture, it is possible to reuse the material after crushing and wetting and to form new elements;
• blocks can be defragmented and mixed with the compost and used as a soil.

Earth substrate (on green roof):

• can be collected and used one more time as a soil.

4.2.3. Scenarios for Wood Elements

General reuse strategies for wood:

• wood unsuitable for structural reuse can be repurposed in garden architecture, such as pergolas, planters, fencing, or tool sheds;
• clean, untreated wood may be processed into particleboard or plywood, or used in glulam production;
• small off-cuts may serve as material for craftwork, decorative details, or custom furniture parts;
• low-grade or damaged dry wood without chemical treatments can be used as biomass fuel (e.g., firewood, wood chips);
• fine wood waste (e.g., sawdust, shavings), if free from contaminants, can be composted or applied as a carbon-rich soil amendment.

Timber structural elements as rafters 14 × 28 cm, purlin 14 × 28 cm, wall plates 14 × 14 cm, timber frame, lintels:

• disassembled structural components should be tested for strength by non-destructive methods. In the case of positive results allowing their reuse as structural components, they should be labeled and properly stored to preserve their parameters;
• if deemed unsuitable for reuse as structural elements, they can be cut into smaller pieces and used as interior finishes (floor, walls, celling) or for furniture.

Wood building elements such as windows, doors, and curtain wall frames:

• after carefully dismantling, they can be used as partition walls or greenhouses, or for building external walls in a warmer climate.

Wood finishing materials such as planed boards finished with matt varnish and wood sills:

• after carefully dismantling, they can be cleaned and used one more time.

Wood materials without visual esthetic application, such as boarding (on the flat roof) or impregnated boards:

• repurposed for the construction of sheds, storage units, or fences in technical or agricultural contexts;
• if unsuitable for reuse due to damage or degradation, they can be used as fuel in biomass systems—provided no toxic preservatives are present;
• wood covered with bitumen or tar paper can be incinerated in specialized waste facilities or cement plants equipped with flue gas treatment and permits for co-incineration of bituminous waste;
• impregnated wood containing biocides or heavy metals must be handled as hazardous waste and disposed of in compliance with environmental regulations.

4.2.4. Scenarios for Glass Elements

Double glazing in windows, doors to the veranda, and curtain wall on the veranda:

• in case of damage and breakage, the glass can be used as raw material for foam glass production;
• after crushing, it can be used as glass grit for finishing applications (with mortar or plaster), for producing different elements, or for use in gabions;
• larger intact glass sheets can be cut and reused for non-structural glazing applications, such as interior partitions, greenhouse panels, or furniture inserts (e.g., tabletops, cabinet doors);
• finely ground waste glass (glass powder) can be used as a partial substitute for cement in concrete or mortar, reducing CO₂ emissions and enhancing durability [50];
• in landscaping, crushed glass can be used as an aggregate for permeable surfaces, decorative mulch, or filler in drainage layers;
• recycled glass can also be used in the production of glassphalt—an asphalt mix that includes crushed glass, improving reflectivity and grip [51];
• clean container and flat glass waste can be used as a raw material in glass wool insulation, replacing virgin inputs such as sand and soda ash; increasing cullet content by 10% can reduce energy consumption in glass melting by up to 3% and significantly lower process-related CO₂ emissions [52].

4.2.5. Scenarios for Stone Components

Mineral wool (wall insulation roof 22 cm):

• if the mineral wool is dry, clean, and mechanically intact, it can be reused in non-load-bearing thermal insulation applications such as garden structures or sheds;
• contaminated or damaged material should be disposed of in accordance with construction waste regulations, as reuse can pose a health hazard (due to the release of fibers or mold);
• in some cases, mineral wool waste can be mechanically compacted and reused as filler in non-critical thermal or acoustic layers;
• if they are not suitable for reuse, they can be sent to mineral wool recycling plants, where they are melted down and processed into new insulation products or used as a substitute for aggregate in lightweight concrete.

Pebbles stone (plinth):

• can be recovered, cleaned, and reused in landscaping, decorative gravel beds, or permeable surface layers;
• may be integrated into drainage systems or used as fill for gabion baskets or retaining structures;
• smaller or partially broken pebbles may be reused as bedding material under pavements or foundations.

Cut stone (floor and ramp):

• intact elements may be carefully removed and reused in flooring, steps, thresholds, or wall cladding in new buildings;
• damaged or broken stone can be cut into smaller tiles or used as crushed aggregate in construction or landscaping;
• esthetically unique fragments may be reused in mosaic finishes, garden paving, or as decorative facing stone.

4.2.6. Scenarios for Metal Elements

• steel elements such as posts, chains, gutters, or pipes can be directly reused in construction if they are not corroded or deformed—especially in secondary structures, formwork, or technical installations;
• flat metal sheets (e.g., zinc-titanium flashings, parapets, chimney caps) can be cut and reused as cladding, flashings, or protective panels on facades, roofs, or interiors;
• zinc-titanium air ducts can be flattened and reshaped for use in custom metalwork, furniture design, or artistic and architectural applications;
• if reuse is not possible, all metal components should be sorted by material type (e.g., steel, zinc, aluminum) and sent for recycling—significantly reducing the environmental impact compared to the original extraction and processing;
• recycled metals can re-enter the construction cycle in the form of rebar, sheet metal panels, hardware or structural frames, supporting a closed-loop economy in the construction sector.

4.2.7. Scenarios for Ceramic Components

Ceramic tiles (e.g., kitchen and toilet):

• if undamaged, tiles can be carefully removed and reused in similar wall applications or decorative wall cladding;
• chipped or broken tiles can be crushed and reused in trencadís mosaics or as decorative infill in landscape paving;
• fragments may also be used as a backfill or drainage layer in non-structural applications.

Stoneware tiles in the toilet:

• intact tiles may be cleaned and reused in new floors or wall finishes, especially in utility spaces or outdoor paving;
• damaged tiles can be crushed and used as aggregate in concrete or as ceramic gravel in garden paths and sub-base layers;
• fine ceramic waste may be used as a partial replacement for natural aggregate in mortars or as thermal mass filler in low-tech construction.

4.2.8. Scenarios for Other Materials and Units Identified in the Building

Polystyrene foam (slab on the grade):

• expanded polystyrene (EPS) waste is significantly more difficult to recycle into its original form than many other plastics. Due to its low density, high volume, and challenges in collection and processing, a large proportion of EPS ends up in landfills.
• crushed and mixed with cement and sand to produce lightweight insulating material or infill for non-structural elements; such a mix can be used in the production of insulating mortars or lightweight concrete, including aerated concrete blocks [53];
• re-melting and granulation after cleaning, allowing for the production of new EPS-based products;
• dissolution in organic solvents, such as limonene, to reduce transport volume; the dissolved EPS is transported to specialized facilities, where the polymer is recovered [33,34];
• production of waterproofing agents from dissolved EPS, as developed at the Warsaw University of Technology; the resulting material may be further modified with additives such as pigments, flame retardants, and stabilizers [35,53].

Bitumen membranes (e.g., asphalt felt in foundations, green roof):

• bitumen membranes can be mechanically separated from wood or other substrates; this process is easier when the membrane is heated;
• recovered bitumen membranes can be sent for energy recovery in cement plants or asphalt recycling in the road industry.

VCL (vapor control layer):

• often damaged during deconstruction, but, if intact, may be reused as a moisture barrier in low-demand technical applications;
• otherwise, treated as construction plastic waste and sent to appropriate recycling or energy recovery streams.

Wind barrier foil (thin polymeric membrane):

• if removed without tearing, can be reused in temporary protective layers (e.g., during construction);
• if damaged, qualifies as mixed plastic waste—recycling may be limited depending on local infrastructure.

Geomembrane (e.g., green roof):

• if undamaged and not penetrated by roots, can be reused as a drainage layer separator in green roofs or large planters;
• if compromised, considered non-recyclable plastic waste, and must be directed to energy recovery or landfill, depending on contamination level and local policy.

4.3. Scenarios and Results of End-of-Life Analysis of Earth Technologies According to LCA

The available literature lacks comprehensive carbon footprint analyses of the end-of-life stage (Modules C1–C4) associated with the demolition process and transportation of recovered materials. This phase is difficult to estimate due to its hypothetical nature and the need to make assumptions about future activities and demolition and logistics technologies. For the purpose of this study, an attempt was made to analyze the end-of-life of C1–C2 modules of earth walls in a building in Pasłęk for various selected scenarios.

To assess the reuse potential of earth materials from demolition, both technical and environmental factors must be evaluated. Key parameters include granulometry, compaction, plasticity, strength, and the presence of stabilizers like cement or lime. Such additives limit reuse in composting or land reclamation. Materials without binders, retaining structure, may be rehydrated or reused. A multidisciplinary analysis ensures safe reintegration into construction or nature.

In the case of the experimental building in Pasłęk, as indicated earlier, the soil used for the structural and exterior walls was obtained locally—from excavations made on the building plot. The excavated soil mixture, also used for the foundations, consisted of sand, silt, clay, and 8% Portland cement, acting as a stabilizer.

Three earth technologies were used in the building: rammed earth, adobe bricks, and compressed earth bricks. They were used in two types of partitions:

• The exterior walls, which consist of a 40 cm thick rammed earth bearing layer and an interior layer of adobe bricks (clay and straw), which were left exposed or covered with clay plaster.
• The partition walls were made of dried pressed earth blocks, produced from the same mixture as the rammed earth layer. The partition walls are 14 and 29 cm thick and are left unfinished—with no additional surface finish.

In order to estimate the potential impact of the end-of-life stage (C1–C2) on the building’s carbon footprint, alternative scenarios for the demolition and reuse of earth materials were developed. The scenarios differ in both the method of dismantling the structural elements (manual or mechanical demolition) and the potential transportation—depending on the adopted scenario for further use of the raw materials. The results of emission calculations for each scenario are summarized in

Table 3. Summary of selected scenarios adopted for the analysis of C1 and C2 modules.

Scenario	Demolition Method	Waste Management	Transport Distance [km]	GWP C1 (kgCO2e)	GWP C2 (kgCO2e)	GWP C1–C2 (kgCO2e)	GWP C1–C2 (kgCO2e/m3)
A1	Manual	On-site brick reuse (in situ recycling)	0	0	0	0	0
A2	Manual	Off-site brick reuse	50	0	750.40	750.40	11.56
A3	Manual	Off-site brick reuse	100	0	1500.80	1500.80	23.11
A4	Manual	On-site backfilling	0	0	265.32	265.32	3.68
B1	Mechanical	On-site brick reuse (in situ recycling)	0	51.47	0	51.47	0.71
B2	Mechanical	Off-site brick reuse	50	51.47	750.40	801.87	12.27
B3	Mechanical	Off-site brick reuse	100	51.47	1500.80	1552.27	23.83
B4	Mechanical	On-site backfilling	0	51.47	0	316.79	4.39

and Figure 3.

Manual demolition involves the use of tools that do not require power (e.g., hammers, crowbars), resulting in minimal direct impact on GHG emissions. Indirect emissions, if any, may be associated with transporting additional workers to the demolition site or increased energy requirements of the human body during intense physical exertion. A significant advantage of manual demolition is the increased potential for recovering materials intact, which can reduce the need for new raw materials and reduce the overall carbon footprint [54].

Mechanical demolition is expected to use heavy equipment such as excavators and jackhammers. This method has higher fuel consumption and CO₂ emissions, but shortens the duration of the work and requires fewer workers.

Three potential paths for the use of the demolition residue were considered: (1) backfilling with soil of the excavation created after the building (local closure of material circulation), (2) the production of compressed bricks at the demolition site, and (3) production of the same elements in an industrial plant located 50 or 100 km from the construction site.

The results of the calculations confirm previous observations by other authors, indicated in previous sections of the paper, regarding the significant impact of material logistics on the total carbon footprint of earth-based solutions.

Analysis of scenarios A3 and B3, which assume the longest distance of material transport to the production facility (100 km), showed that they are the most carbon-intensive of all the options considered. In these scenarios, the impact of transportation significantly exceeds the emissions associated with the demolition process itself.

In contrast, the lowest emissions were recorded in scenarios involving manual demolition and local management of the excavated material, without the need for transport over longer distances. These results confirm that the most environmentally efficient approach is to reuse the soil on site—provided that the physical and chemical properties of the soil allow for its safe and functional use in construction.

It should be noted, however, that, in some countries, existing regulations may limit the possibility of local management of demolition soil. Even if the soil meets the criteria for inert waste, administrative regulations may prohibit its secondary use in native soil or in earth construction [55].

In situations where the soil is classified as contaminated or its properties prevent its use as a secondary raw material for building components, it is possible to use it in road infrastructure—for example, as material for structural layers or for forming embankments. Such use, although less preferable from the point of view of closing the material cycle within a building, still fits into waste management strategies, in line with the materials hierarchy.

Importantly, the possibility of the future use of demolition soil brings additional environmental benefits for downstream products, as it reduces energy-intensive processes such as excavating fresh soil with excavators, transporting it, and preparing the appropriate mixes. Reducing these steps means less fossil fuel consumption, lower dust and noise emissions, and a reduction in the need for new raw materials. Such benefits can be included in a life-cycle analysis (LCA) as so-called negative emissions in Module D (benefits and loads beyond the system boundary), which describes the impact of the potential reuse or recycling of materials at the end of a building’s life.

5. Conclusions and Perspective on Future Challenges

The design assumptions adopted for the construction of building partitions in earthen technologies with an earth plaster finish or left without a finishing layer allowed for minimizing construction waste during demolition. Leaving the walls raw has advantages in terms of material circularity and recoverability. In the case of finishing the partitions, materials that integrally combine with the elements’ components were selected, thereby eliminating the need to separate individual layers during demolition.

Thanks to the possibility of integrating and recycling finishing materials together, waste generation can be significantly reduced. The potential for near-complete material recovery represents a major advantage of earthen construction technologies compared to conventional systems, particularly those relying on cement-based plasters.

Due to the high vapor permeability of earth-based walls, indoor humidity regulation can be achieved, which may reduce the need for extensive waterproofing solutions, especially in the plinth zone. In addition, the high regenerability of earthen materials (particularly adobe and straw–clay blocks) enables the re-creation of elements of varying size without generating production waste and without reliance on strict modularity. This flexibility highlights the importance of selecting technical and material solutions already at the design stage to maximize future reuse potential and minimize end-of-life waste generation.

This study is based on a geographically specific case study located in Poland and reflects local climatic conditions, material availability, construction practices, and regulatory context. Consequently, the absolute emission values reported should be interpreted as context-dependent. However, the primary objective of the study is to demonstrate transferable mechanisms rather than to provide universally applicable numerical results. In particular, the relative influence of the demolition method (manual versus mechanical) and transport distance on end-of-life emissions is independent of location and can be adapted to other regions by applying locally relevant input data. This distinction between context-dependent values and transferable relationships underpins the broader applicability of the proposed analytical framework.

The feasibility of substituting cementitious stabilizing additives in the earth mixture in this type of earth-based development should be investigated. In the case of the Pasłęk building, Portland cement was used, which significantly increases the embodied carbon footprint as well as possibly hindering future use after demolition. In the case of thermal insulation materials, a better solution might be to replace expanded polystyrene (EPS) and mineral wool with materials that are easier for future demolition or disposal and have a lower carbon footprint, such as bio-based materials. From an energy-efficiency perspective, buildings designed to meet current legal requirements may fall below regulatory thresholds over relatively short time horizons. Designing buildings to higher-than-minimum energy standards—where economically justified, for example, through life-cycle cost (LCC) analysis—can extend service life and reduce the need for complex and resource-intensive retrofits.

Alternative stabilizing agents, such as fly ash and natural fibers, should be regarded as promising research directions rather than ready-to-use design solutions. Their application raises challenges related to long-term durability, chemical stability, and environmental safety, particularly in alkaline environments. The potential degradation of organic fibers, interactions between fibers and alkaline binders, and the risk of leaching from industrial by-products require further investigation and careful formulation. These aspects represent important technical limitations and highlight the need for additional experimental research and long-term performance assessment before broader implementation in construction practice.

The practical implementation of the proposed material reuse scenarios may be constrained by technical, economic, and regulatory factors. In particular, fire safety requirements, material certification procedures, contamination risks, and compliance with local building regulations may limit the formal reuse of certain materials, especially in regulated construction markets. These constraints constitute important limitations of the presented scenarios and emphasize the context-dependent nature of their applicability.

It is important to properly plan demolition in a way that allows for the greatest possible recovery of materials. Analyses of individual demolition scenarios should be carried out, taking into account the various forms and possibilities for the use of construction waste. The use of digital twin models supported by BIM data will make it possible to trace possible conflicts, difficulties, and the appropriate sequence of the various phases of demolition. The proposed methodology should be implemented for new buildings already at the design stage, so that design solutions can be verified in terms of technical and material solutions. Introducing such analyses into the conceptual design phase in a simplified manner using average values referenced to the unit of measure for individual technologies can allow environmentally responsible design decisions to be made in shaping architectural solutions through the selection of technical and material solutions, which will be particularly important in the case of hybrid technologies. More detailed data should be incorporated during the implementation phase to support the selection of appropriate construction details and connection strategies. It is therefore postulated that demolition planning and material reuse assumptions should form an integral part of the design process for newly designed buildings, especially those intended to achieve high environmental performance, and should be considered within sustainability certification frameworks.

An impediment to the implementation of the postulated solutions is the lack of data on the environmental impact of different demolition methods for individual technical and construction solutions. In this regard, detailed studies should be carried out, taking into account the man-hours of equipment and people, the necessary tools in the case of manual work, the energy intensity of the demolition power tools used, the percentage of destruction of materials through the use of a particular demolition, and the possible types of fractions to be recovered and reused. In addition, another aspect that should be analyzed in more detail is the possible reuse of demolition materials. In order to implement these issues into the execution of demolition and material reuse projects, it is necessary to create a global database of potential reuse and processing of construction materials. These data should be more accurately included in the EPD (Environmental Product Declaration), indicating the possibilities for the reintroduction of various waste streams. The solutions presented should be based on research conducted by scientific and industrial units and on a collection of good practices, in particular in the field of low-tech solutions. The emerging catalog should be an open source and open access database (respecting patent practices) to strengthen the effect of the emergence of new qualitative pro-environmental solutions in the construction industry and the dissemination of circular solutions.

In this context, it becomes particularly important to create circular plans for waste management in organizations, especially scientific and research units. In this way, it would be possible to expand the search for waste utilization to also include non-construction waste, which could be used in construction. Shaping the circularity strategy of public facilities could be an important factor in allowing circular solutions to be popularized and put into practice.

Attention should also be paid to the need for urban-planning analyses of the location of selective collection points for construction waste in terms of material bank solutions, as well as points for processing construction waste and producing construction regenerative products with high technical utility values produced from construction waste. The location of such elements of the circular chain should be analyzed in view of the potential carbon footprint of transportation.