Small-Scale Public Rental Housing Development Using Modular Construction—Lessons learned from Case Studies in Seoul, Korea

Round  1

Reviewer 1 Report

The paper is well structured and documented.

The motivation of the feasibility and economic and social sustainability of the interventions is clear, but the discussion of the environmental sustainability of the modular off-site construction could also be enhanced.

Check the presentation of the statistical data on lines 104-110; I detect a problem of order of magnitude of the data (millions and thousands)

Author Response

Dear reviewer,

We appreciate your comments.

Following your comments, we have revised manuscript as follows.

Point 1: The paper is well structured and documented.

The motivation of the feasibility and economic and social sustainability of the interventions is clear, but the discussion of the environmental sustainability of the modular off-site construction could also be enhanced.

 Response 1: We appreciate your comments. Following your comments, we have add 6.3 section (line number from 430 to 460) relating a modular construction project’s environmental sustainability aspects from a perspective of public developer based on three modular construction projects cases. In short, there were two environmental benefits of modular construction from the perspective of public developer. First, modular construction has the effect of resource saving and productivity improvement by minimizing rework. Second, environmentally friendly technology can be applied at a lower cost than conventional construction method.

 Point 2: Check the presentation of the statistical data on lines 104-110; I detect a problem of order of magnitude of the data (millions and thousands)

 Response 2: We appreciate your comments. Following your comments, we have revised the descriptions of magnitude of the data (line number from 124 to 130).

(Before)

Statistics Korea (2018) data indicate that the number of households with one or two people in was ~364 million (44.0%) in 2010 and will reach 515 million (53.8%) in 2020 and 640 million (60.5%) in 2030 [17]. Due to large-scale development in the city centre involving reconstruction and redevelopment, however, small single and multi-family houses have been destroyed. In recent years, the inventory of small houses (32 m2 or less) has decreased from 573,000 households (10.8%) in 1980 to 252,000 (2.0%) in 2005.

 (Current)

Statistics Korea (2018) data indicate that the one or two-people households were 3,640,000 (44.0%) in 2010 year in Korea. It is also expected that it will be 5,150,000 households (53.8%) in 2020 year and 6,400,000 households (60.5%) in 2030 year [27]. Due to large-scale development in the city centre involving reconstruction and redevelopment, however, small-single and multi-family houses have been destroyed. In recent two decades, the number of small-scale houses (32 m2 or less) has decreased from 573,000 households (10.8%) in 1980 year to 252,000 households (2.0%) in 2005 year.

Again, thank you for your dedication.

Sincerely,

Jeonghoon, Lee.

Author Response File: Author Response.docx

Reviewer 2 Report

The paper "Small-Scale Public Rental Housing Development Using Modular Construction in Korea_ Lessons  learned from Case Studies" is a well-organized work, however some corrections are needed>

- for a research paper introduction and other chapters should be based on little more extensive references.Therefore, I suggest an improvement of the references.

- the fonts and the size of the text in the figures must be unitary. Please review! (ex. fig. 1, 2, 3 and, 4 - very large text, disproportionate to each other.

Author Response

Dear reviewer,

We appreciate your comments. Following your comments, we have revised manuscript as follows.

Point 1: The paper "Small-Scale Public Rental Housing Development Using Modular Construction in Korea_ Lessons learned from Case Studies" is a well-organized work, however some corrections are needed>

- For a research paper introduction and other chapters should be based on little more extensive references. Therefore, I suggest an improvement of the references

Response 1: We appreciate your comments. Following your comments, we have added several references to enhance the introduction section (line number from 40 to 49, from 53-58), literature review section (line number from 107 to 117), and Discussions section (line number 445 and 447). Also, these references were inserted in References section (line number 484).

Line number from 40 to 49: Following Butlin (1989), Bruntland (1987) defines sustainable construction as “development that meets the needs of present without compromising the ability of future generations to meet their own needs”[1-2]. Current sustainable construction goals are focusing on improved efficiency [3], waste minimization and pollution prevention [4]. WBDG (Whole Building Design Guide) defines “the main objectives of sustainable design are to reduce, or completely avoid, depletion of critical resources like energy, water, land, and raw materials; prevent environmental degradation caused by facilities and infrastructure throughout their life cycle; and create built environments that are livable, comfortable, safe, and productive.”[5]. Considering both sustainable construction and sustainable design definitions, current construction industry faces challenge of finding new ways to replace existing construction methods at the beginning of the design stage.

Line number from 53 to 58: Fred et al. (2016) investigated that performance of modular prefab construction based on case study. This paper introduced several modular construction cases and organized five performance investigation categories; thermal behaviour, acoustic constraints, seismic resistance, energy consumption, and lift cycle analysis. One of the research results shows that mass customization is one of the important factors to commercialization of modular construction [11].

Line number from 107 to 117: In Malaysian, Sustainable Modular Industrialized Building System (IBS) has been adopted from 2006 [23]. Its main goals are reducing dependency on foreign labor and saving country’s loss in foreign exchange [8, 24]. The Modular IBS also provides improved solutions relating reduce the environmental effect based on sustainable construction design. Despite those advantages, sustainable design concept for modular construction is difficult to designers and architects because of lack of understanding of modular process [25]. Pan et al (2007) investigated UK housebuilders’ views on the modular construction using extensive questionnaire survey of top 100 housebuilders [26]. The research results show that complex interfaces and design challenges (difficult to satisfy the standard design concept considering manufacturing and site installation environment) still exist in modular construction. In other words, design standardization can be both an advantage and a disadvantage of modular construction.

Line number 445 and 447: For quantitative measurement and motivation of this, LEED certification or national green building construction certification has been used in worldwide [31-33]. These certifications have several specific categories and measurement methods, so project owner or designer can choose these items to achieve reasonable certification level, taking into account the total project budget, design characteristics, and building type [34].

  Point 2: the fonts and the size of the text in the figures must be unitary. Please review! (ex. fig. 1, 2, 3 and, 4 - very large text, disproportionate to each other.

Response 2: We appreciate your comments. Following your comments, we have revised figure size and fonts in Figure 1 through Figure 4.

(Figure 1: line number 176, Figure 2: line number 183, Figure 3: line number 223, Figure 4: line number 227).

- Please refere to the attatched Word file. 

Author Response File: Author Response.docx

Round  2

Reviewer 2 Report

Dear authors,

I consider that the second version of the paper is much improved. The work can be published in present form.