INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

A Comparative Study on the Environmental Impact of Cast-in-Situ

(Cis) and Industrialized Building System (IBS): A Life Cycle

Assessment Approach

Chou Tze Ying and Wan Mohd Sabki Wan Omar*

Faculty of Civil Engineering & Technology, University Malaysia Perlis (Uni MAP), 02600 Arau, Perlis,

Malaysia.

DOI: https://doi.org/10.47772/IJRISS.2025.91200049

Received: 11 December 2025; Accepted: 18 December 2025; Published: 31 December 2025

ABSTRACT

This study aims to investigate the embodied energy (EE) and embodied carbon (EC) of cast-in-situ (CIS) and

industrialized building system (IBS) methods in the construction phase of residential buildings within the

Malaysian construction industry. The objectives are to determine the EE and EC values for both methods and

recommend the most environmentally sustainable option. A Life Cycle Assessment (LCA) was conducted using

Staad Pro V8i software to model and analyse the building components. The study found that the IBS method

consistently resulted in the lowest EE (GJ/m²) and EC (tCO₂e/m²) values across all building types, with the 2-

storey bungalow achieving the lowest values. It was observed that the total floor area, building materials, and

component sizes significantly impact the EE and EC results. The research concludes that these factors are critical

in minimizing the environmental footprint of residential buildings, thereby achieving the study's objectives of

identifying the most sustainable construction method.

Keywords: Life Cycle Assessment, Industrialized Building System, Cast-In-Situ

INTRODUCTION

According to ISO 14040[1], defining system boundaries and functional units is essential in conducting a life

cycle assessment (LCA). This study focuses on evaluating the environmental impacts, specifically EE and

greenhouse gas (GHG) emissions, in the manufacturing process of residential buildings using CIS and IBS in

Malaysia. Given the limited research on EE in building construction and the pressing need to address GHG

emissions, these aspects are the primary objectives of this LCA. The scope of the LCA is crucial for determining

which environmental issues are addressed [2].

Various LCA methodologies, such as cradle-to-grave, cradle-to-gate, and cradle-to-cradle, have distinct

boundaries and objectives [3, 4]. Cradle-to-grave assesses the entire lifecycle from construction to demolition,

while cradle-to-cradle emphasizes material recycling. Cradle-to-gate, selected for this study, focuses on the

production and construction phases up to delivery, excluding reuse and disposal processes outside the defined

boundaries [2].

The environmental impacts assessed include EE and EC, which are critical metrics for evaluating the

sustainability of building materials and methods. EE refers to the total energy consumed throughout a product's

lifecycle, while EC measures the carbon emissions from production, use, and disposal [2]. These metrics help

identify the environmental footprint of construction methods, guiding decisions to mitigate impacts.

Utilizing LCA as a methodological framework, this study aims to analyze and compare the EE and EC of CIS

and IBS methods during the manufacturing phase of residential buildings in Malaysia. It seeks to recommend

the most sustainable construction method to optimize environmental performance, supporting global initiatives

to reduce environmental impact and enhance resource efficiency in the Malaysian construction industry.

Page 555

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

LITERATURE REVIEW

Embodied Energy (EE)

According to Mohd Safaai, Zainon Noor [5], energy consumption in Malaysia increased dramatically between

2000 and 2010 as a result of the country's economic expansion. The entire energy stored in building materials

during the stages of manufacture, construction, and final destruction and disposal was referred to as EE [6]. It

included the energy required for the extraction of raw materials, transportation, the production of building

materials, and the many procedures involved in building and demolishing a structure [7]. EE could be classified

into two categories: on-site direct energy consumption and off-site indirect energy use for material manufacture

and transportation [8]. Indirect energy was widely used in the production of materials and may be found at all

stages of the process, including primary, refurbishment, and deconstruction [7]. The overall energy needed to

create a structure, which included the indirect energy needed to manufacture the building's materials and

components as well as the direct energy consumed during construction and assembly [7].

Embodied Carbon (EC)

According to Wyckoff and Roop [9], the concept of EC emerged from their analysis of the carbon content in

manufactured products involved in international trade. Various case studies have assessed EC in residential

buildings. Early studies focused on measuring the amounts and sources of EC and their impact on overall life

cycle carbon emissions. The emissions of GHG associated with building construction were measured by EC.

This included the emissions from raw material processing, building material and component manufacturing,

transportation to the construction site, and building component assembly [10]. In order to quantify the effect of

GHG emissions, a global warming potential (GWP) was assigned to each GHG in order to provide a standard

comparison known as carbon dioxide equivalent (CO₂e) [11].

Life Cycle Assessment (LCA)

According to Delnavaz, Norouzianpour [2], LCA was a process that involves assessing a product's

environmental impact throughout its entire lifespan, aiming to improve resource efficiency and reduce

environmental harm. It analysed the environmental burdens associated with processes and products over their

entire life cycle, as shown in Figure 2.1. This assessment covered every stage of a product or process, including

manufacturing, construction, operation, maintenance, and end-of-life phases[3, 4]. According to ISO14040 [3],

LCA consisted four stages, which were goal and scope definition, life cycle inventory (LCI), life cycle impact

assessment (LCIA), and interpretation of results [3]

LCA examined the environmental impact of a product from raw material extraction to disposal. It considered

ecological impacts, effects on human well-being, and resource use [3]. The LCA process involved defining the

study's goals and scope, conducting LCI, performing LCIA, and interpreting the data. It highlighted the

environmental benefits of new building methods, encouraging engineers to consider them in design.

Additionally, the results could set a standard for future studies [2].

Figure 1: Life cycle stages of buildings

Page 556

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

The EE and EC Reduction through LCA

LCA played a crucial role in reducing EE and EC in the construction industry. By systematically evaluating the

environmental impacts of building materials and processes from the extraction of raw materials to the end of

their life cycle, LCA provided a comprehensive understanding of where and how energy and carbon emissions

were generated [7]. This holistic view allows stakeholders to identify and quantify the sources of EE and EC,

enabling informed decision-making to minimize these impacts. In essence, LCA served as a vital tool for

achieving sustainable construction by pinpointing areas for improvement and guiding the implementation of eco-

friendly practices [2, 3].

The existing body of research provided valuable insights into the application of LCA in various contexts. Table

2.1 summarized key studies, highlighting their locations, building types, building phases analysed, and the

specific LCA boundaries employed.

Table 1: The phases and methods used by different researchers

Sources

Location

Malaysia

Building Type Building Phase

LCA

Boundary

Method

Lu and Wan Omar [12]

Wan Omar, Doh [13]

Residential

Manufacturing

Phase

Cradle-to-

gate

Software

Manufacturing

Phase

Cradle-to-

gate

Case Study

Abouhamad and Abu-Hamd Egypt

[14]

End of Life Phase

Cradle-to-

grave

Zhang, Sun [15]

China

USA

Residential

Commercial

Residential

Commercial

Residential

Manufacturing

Stage

Cradle-to-

gate

Case Study

Software

Zhao, Xu [16]

Construction

Stage

Cradle-to-

gate

Basbagill, Flager [17]

Haddad, Sedrez [4]

Siti Halipah, Zaini [6]

Operational Phase -

Software &

Case Study

Brazil

Malaysia

Construction

Phase

Cradle-to-

gate

Case Study

Construction

Phase

Cradle-to-

gate

Case Study

Delnavaz,

[2]

Norouzianpour Iran

Construction

Phase

Cradle-to-

gate

Software &

Case Study

Zaini, Siti Halipah [18]

Malaysia

Australia

Manufacturing

Phase

Cradle-to-

gate

Software

Mohebbi,

Jahromi [11]

Bahadori- UK

Manufacturing

Phase

Cradle-to-

gate

Helal, Stephan [19]

Page 557

Manufacturing

Phase

Cradle-to-

gate

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Khasreen, Banfill [20]

UK

Commercial

Residential

Construction

Phase

Cradle-to-

gate

Case Study

Zabalza Bribián, Aranda Spain

Usón [21]

End of Life Phase

Cradle-to-

grave

Hui and Ma [22]

Hong Kong Residential

Operational Phase -

Case Study

Blengini and Di Carlo [23]

Wan Omar [24]

Italy

Residential

Operational Stage

-

Malaysia

Manufacturing

Stage

Cradle-to-

gate

Zhang, Chen [25]

China

Residential

Commercial

Operational Stage

-

Case Study

Xiang, Mahamadu [26]

Manufacturing

Stage

Cradle-to-

gate

These studies showcased a diverse range of applications and findings, highlighting the versatility and

significance of LCA in various building contexts and phases. Through an examination of these different research

efforts, a clearer understanding of global trends and best practices in reducing EE and EC through informed LCA

methodologies was gained. This comparison emphasized the necessity of tailoring LCA approaches to specific

regional and building type contexts to achieve the most effective outcomes.

METHODOLOGY

Based on Figure 1 below, this study analyses how various building components affect the environment in

residential homes by measuring their EE and EC values. Using advanced software like Staad Pro V8i, it models

and assesses components such as walls, roofs, bars, and rods. By standardizing material volumes and weights

into MJ/m³ for EE and kgCO_2e/m³ for EC, the research aims to evaluate sustainable building designs, particularly

in Malaysia. Total EE and EC have been normalized by dividing floor area of each model for comparison across

studies. These findings offer insights into eco-friendly design options and advocate for sustainable construction

practices.

Figure 2: Methodology Flowchart

Page 558

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Development of Models

This study examines the environmental impacts of different construction methods used in Malaysian residential

buildings, focusing on 1-storey, 2-storey, and 4-storey bungalows. These structures range in size from 201.69

m² to 1259.75 m², utilizing reinforced concrete columns, beams, slabs, concrete brick walls, and various roof

designs. By analysing architectural and structural details, the research aims to highlight the materials,

dimensions, and technical specifications crucial for each building type, providing insights to improve industry

standards, urban planning regulations, and promote sustainable building practices in Malaysia.

The first type is the 1-storey bungalow, which encompasses a building area of 201.69 square meters. This

structure is supported by reinforced concrete (RC) columns, beams, and slabs. The walls are made of concrete

bricks, providing robust support and insulation. The roof is a gable design, utilizing size ISA75505 and ISMC75

components. The second type is the 2-storey bungalow, which has a significantly larger building area of 353.01

square meters. Similar to the 1-storey bungalow, it features RC columns, beams, and slabs for its structural

framework and concrete brick walls for added stability and durability. The roof is also a gable design with the

same size components, ISA75505 and ISMC75, ensuring consistency in the structural design across these two

types of bungalows. The third type is the 4-storey bungalow, which includes a basement, shear walls, and a lift,

making it the most complex structure among the three. It covers a vast building area of 1259.75 square meters.

This bungalow is built with RC columns, beams, and slabs, similar to the other two types, and also features

concrete brick walls. However, instead of a gable roof, it has a flat slab roof with L20204 components,

accommodating the additional structural requirements of the basement and lift system.

Figure 3: 1-Storey Bungalow

Figure 4: 2-Storey Bungalow

Figure 5: 4-Storey Bungalow

Page 559

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Using Staad Pro V8i

The methodology for this study involves the use of Staad Pro V8i software to model and analyse the building

components of residential structures constructed using CIS and IBS methods. Staad Pro V8i, a powerful

structural analysis and design tool, facilitates precise calculations of structural dimensions and material usage.

By inputting various building parameters into the software, such as material types, wall thicknesses, roof

systems, and structural components, the study effectively assesses the EE and EC for each construction method.

This comprehensive analysis enables a detailed comparison of the environmental impacts associated with the

CIS and IBS methods during the manufacturing phase of residential buildings in the Malaysian construction

industry.

Figure 6: Inputting building dimensions using Staad Pro V8i

Data Collection

To know what materials are needed for a building project, it's essential to carefully study the construction

drawings. These drawings show the architectural and structural details of the project. By interpreting symbols

and notes on the drawings, this research can understand the materials, dimensions, and technical specifications

required for the project. This helps us determine the important aspects of the building project. Once the

information from the construction drawings is gathered, it's easier to understand the materials needed for the

project. This knowledge is crucial for comparing the environmental impact and effectiveness of different

materials in various building projects.

Figure 7: Construction Drawing of 4-Storey Bungalow

Page 560

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Application of Life Cycle Assessment (LCA)

LCA is a comprehensive method used to evaluate how products impact the environment throughout their entire

life cycle, from raw material extraction to disposal. It considers ecological impacts, effects on human well-being,

and resource use [27]. The process of LCA involves several key steps: defining the study's goals and scope,

conducting a LCI to quantify material and energy inputs, performing a LCIA to evaluate environmental effects,

and interpreting the data to draw meaningful conclusions [2]. By highlighting the environmental benefits of

construction methods, such as CIS and IBS, LCA encourages engineers and designers to consider sustainability

in their decision-making processes, setting benchmarks for future studies.

In the context of Malaysian residential construction, LCA plays a crucial role in comparing the environmental

impacts of CIS and IBS methods during the manufacturing phase. This research focuses on assessing EE and

EC impacts, aiming to provide insights into how these methods influence sustainability within the construction

industry [28]. The study employs a functional unit of 1 m² of constructed area to standardize measurements,

ensuring a consistent basis for evaluating the environmental performance of different building methods. This

approach helps in understanding which construction techniques minimize EE and EC outputs, thereby promoting

more environmentally friendly building practices in Malaysia. [2]

Goal and Scope of Boundaries

The first part of the LCA process, called goal and scope definition, sets the purpose and method for including

environmental impacts in decision-making [29]. The goal of this study is to compare the EE and EC in the

manufacturing phase of residential buildings constructed using CIS and IBS methods within the Malaysian

construction industry. By doing so, this study aims to assess how various scenarios impact the reliability of LCA

results for both construction methods, providing valuable insights for environmental decision-making in the

construction sector.

The effectiveness of the product system's functional outputs was evaluated by a functional unit [3]. In the context

of this study, the functional unit is defined as 1 square meter (m²) of constructed area. This unit of measurement

is used to standardize the comparison of the environmental impacts of the CIS and IBS methods. According to

Delnavaz, Norouzianpour [2], the use of the constructed area of materials to compute construction dimensions

provides a consistent and appropriate foundation for the LCA study, ensuring accuracy and comparability in the

assessment of environmental impacts. This approach provides a common basis for assessing the environmental

effect of the two building methods, facilitating a clear and comparative analysis. The choice of 1m² as the

functional unit aligns with previous studies and allows for straightforward comparison and evaluation of the EE

and EC associated with each construction method.

The system boundary determines which processes are included in the LCA. This boundary was influenced by

the study's purpose, assumptions, cut-off criteria, data and cost limitations, and the target audience [3]. For this

project, the system boundary encompasses only the manufacturing phase of residential buildings in Malaysia.

This phase is chosen because it produces the most significant amounts of EC and EE, making it the critical focus

for assessing environmental impacts.

Life Cycle Inventory (LCI)

During the LCI phase, data on material quantities, energy inputs, and GHG emissions are collected and analysed

using methodologies like Process LCI, Input-Output Method (IOM), and Hybrid LCI (HLCI) [12, 30]. These

methods quantify the EE and EC by multiplying the volume of construction materials with their respective

energy and carbon intensities, expressed in carbon dioxide equivalent (CO_2-e) [8]. Advanced software tools such

as Staad Pro V8i are utilized to model variations in construction parameters accurately, enabling a

comprehensive assessment of how changes in material types, structural dimensions, and design elements affect

EE and EC values. According to Lu and Wan Omar [12], the formulas for EE and EC are as follows:

EE_m= W_m× HEI_m

EC_m= W_m× HECO_{2−e m}

www.rsisinternational.org

(3.1)

I

(3.2)

Page 561

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Where, EE_mis the total EE used, W_mis the quantity or weight of material, HEI_mis the construction materials’

EE intensity, EC_mis the total EC produced, and HECO_2−eI_mis EC intensity of the construction materials used.

Sensitivity analysis in this study examines how variations in building materials, sizes, and parameters impact

EE and EC during the manufacturing stage of Malaysian buildings [2]. Key parameters such as material types,

wall thickness, roof system type, and structural component dimensions were varied using advanced software like

Staad Pro V8i. Results indicated that construction material type significantly influences EE and EC values more

than wall thickness or roof system type. Standardizing EE and EC by building area revealed insights into the

impact of building size on environmental performance. This analysis identified critical factors for material

selection and design decisions, reinforcing the study's findings [2, 31].

Life Cycle Impact Assessment (LCI)

Sensitivity analysis in LCI is an important method used in this study to ensure the accuracy of the findings by

examining different scenarios [2]. The main goal is to see how various scenarios impact the reliability of LCA

results. This study aims to understand the effects of these differences during the manufacturing stage of building

in Malaysia by comparing different building materials, sizes, and their environmental impacts.

In this study, sensitivity analysis was conducted to evaluate how changes in various parameters affect the overall

results, specifically the EE and EC values of different building components. The primary aim was to understand

the validity of the findings and identify the key factors that significantly influence the environmental impact of

the buildings. In this research, sensitivity analysis is used to evaluate how different scenarios affect residential

building designs that use CIS and IBS construction methods during the manufacturing stage [31]. Considering

various building designs is expected to improve the accuracy and reliability of LCA findings [2]. This method

helps to reflect the uncertainties and possible variations in the building methods used in Malaysia.

The first step in conducting the sensitivity analysis involved identifying the critical parameters that could vary

during the manufacturing phase. These parameters included the type of materials used (such as GEN2 with 30%

fly ash versus Ordinary Portland Cement), the thickness of the walls, the type of roof system (gable versus flat),

and the dimensions of the structural components like beams, columns, and roof trusses. Each parameter was

systematically varied within a reasonable range to observe its impact on the EE and EC values.

Table 2: EE and EC values of various sizes and materials for 4-storey bungalow

Component

Size

Design

Option

Materials

Concrete Concrete Embodied Energy

Embodied Carbon

kgCO₂e kgCO₂e/m²

325,658.88 1614.65 33,135.456 164.289

Volume

(m³)

Volume

(kg)

MJ

MJ/m²

Highest

Option 1 G30

69.8

167,520

Option 2 GEN

(15%)

1 69.8

108,888.00 539.88

14,741.760 73.091

Option 3 RC 20/25

69.8

167,520

135,691.20 672.77

127,315.20 631.24

19,097.280 94.686

17,757.120 88.042

Option 4 GEN

(0%)

2 69.8

Option 5 RC 25/30

69.8

167,520

142,392.00 705.99

118,939.20 589.71

20,269.920 100.500

16,416.960 81.397

Option 6 GEN

(15%)

2 69.8

Moderate

Page 562

Option

13

G30

42.4

101,760

197,821.44 980.82

20,128.128 99.797

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Option

14

GEN

(15%)

1 42.4

2 42.4

101,760

68,640

66,144.00

77,337.60

72,249.60

82,425.60

86,496.00

327.95

383.45

358.22

408.67

428.86

8,954.880

44.399

Option

15

GEN

(0%)

10,786.560 53.481

Option

16

GEN

(15%)

9,972.480

49.445

Option

17

RC 20/25

RC 25/30

G30

42.4

28.6

11,600.640 57.517

12,312.960 61.049

13,576.992 67.316

Option

18

Lowest

Option

19

133,436.16 661.59

Option

20

GEN

(15%)

1 28.6

2 28.6

44,616.00

52,166.40

48,734.40

55,598.40

58,344.00

221.21

258.65

241.63

275.66

289.28

6,040.320

7,275.840

6,726.720

7,824.960

8,305.440

29.949

36.074

33.352

38.797

41.179

Option

21

GEN

(0%)

Option

22

GEN

(15%)

Option

23

RC 20/25

RC 25/30

28.6

Option

24

Interpretation of Data

In the interpretation phase, LCA findings are reviewed to ensure accuracy, reliability, and alignment with the

study's objectives. Data validation, including comparisons with existing research, enhances the credibility of

results by confirming the consistency and robustness of EE and EC assessments per cubic meter of material.

This thorough approach not only facilitates a clearer understanding of the environmental impacts of construction

methods but also supports informed decision-making towards more sustainable building solutions in Malaysia

and beyond.

Evaluation of Best Models

Identifying the best construction model involves evaluating design alternatives to find the most sustainable and

efficient use of resources. The goal is to minimize EE and EC while ensuring structural integrity and safety.

Using Staad Pro V8i, data on the area and weight of concrete and steel are converted into kilograms to calculate

EE and EC values per m², allowing for direct comparisons between building sizes and types. Models are ranked

based on their EE and EC values, with the lowest EE and EC model recommended as the most environmentally

efficient, promoting sustainable construction practices without compromising safety.

Page 563

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Figure 8: Design Options of Models

RESULTS AND DISCUSSION

Comparison of EE and EC values between two construction methods: CIS and IBS

The comparison of EE and EC values between CIS and IBS methods reveals distinct differences in their

environmental impacts. CIS typically involves traditional on-site construction practices, which often result in

higher EE and EC values due to the intensive labor, extended construction time, and increased material waste.

On the other hand, IBS employs prefabricated components, which are manufactured in controlled factory settings

and then assembled on-site. This method tends to lower EE and EC values because of improved efficiency,

reduced material waste, and optimized use of resources. By analysing the data in Figures 9, 10, and 11, it

becomes evident that IBS generally offers a more sustainable option compared to CIS, as it minimizes energy

consumption and carbon emissions during the construction process. This comparison underscores the potential

environmental benefits of adopting IBS in residential building projects.

The results of the LCA reveal significant differences in the EE and EC between the CIS and IBS methods across

various building types. By referring to Figure 9, the CIS method shows an EE of 1,837.87 GJ/m² and an EC of

156.98 tCO_2e/m². In comparison, the IBS method demonstrates lower EE and EC values at 1,425.96 GJ/m² and

154.68 tCO₂e/m², respectively. This indicates that the IBS method is more energy-efficient and produces fewer

carbon emissions even at this basic level of residential construction.

Figure 9: Comparing total EE and EC for both CIS and IBS in 1-storey bungalow

Page 564

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

1,400,000.00

1,200,000.00

1,000,000.00

800,000.00

600,000.00

400,000.00

200,000.00

-

450,000.00

400,000.00

350,000.00

300,000.00

250,000.00

200,000.00

150,000.00

100,000.00

50,000.00

-

CIS IBS

Figure 10: Comparing total EE and EC for both CIS and IBS in 2-storey bungalow

When analysing the results as shown in Figure 10, the advantages of the IBS method become even more

pronounced. The CIS method for a 2-storey bungalow results in an EE of 1,298.81 GJ/m² and an EC of 110.99

tCO₂e/m², whereas the IBS method achieves substantially lower values of 396.54 GJ/m² for EE and 32.39

tCO₂e/m² for EC. This substantial reduction highlights the efficiency of the IBS method in managing both energy

use and carbon emissions, particularly as the complexity and size of the building increase.

According to the data as shown Figure 11, the trend of IBS outperforming CIS continues. The EE and EC values

for the CIS method are 1,197.75 GJ/m²and 102.22 tCO₂e/m², respectively. In stark contrast, the IBS method

records significantly lower EE and EC values of 371.82 GJ/m²and 30.56 tCO₂e/m². These results demonstrate

the scalability and effectiveness of the IBS method in reducing environmental impacts as the building height and

complexity grow.

1,400,000.00

1,200,000.00

1,000,000.00

800,000.00

600,000.00

400,000.00

200,000.00

-

400,000.00

300,000.00

200,000.00

100,000.00

-

CIS IBS

Figure 11: Comparing total EE and EC for both CIS and IBS in 4-storey bungalow

The comparative analysis across different building types underscores the consistent superiority of the IBS

method in terms of environmental performance. The reductions in EE and EC achieved by the IBS method can

be attributed to its use of prefabricated components, which are manufactured in controlled environments. This

leads to increased efficiency, reduced material waste, and lower energy consumption during the construction

phase. The CIS method, on the other hand, involves more energy-intensive processes and greater material waste,

resulting in higher EE and EC values.

Overall, these findings reinforce the potential of the IBS method as a more sustainable alternative to traditional

CIS construction. By adopting IBS, the construction industry in Malaysia can significantly reduce its

environmental footprint, contributing to global efforts to mitigate climate change. The study highlights the

importance of integrating LCA into the decision-making process for construction projects to identify the most

environmentally efficient building methods and promote sustainable practices in the industry.

Page 565

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

Comparing Various Design Options between the 3 Building Sizes

Structural Components

The lowest data of EE and EC for 1-storey, 2-storey and 4-storey bungalow were given in Figure 12 below. The

results demonstrate that multi-storey bungalows generally have a lower environmental impact per unit area

compared to single-storey bungalows. This finding highlights the potential benefits of vertical construction in

terms of resource efficiency and environmental sustainability. By distributing structural loads and materials

across multiple floors, multi-storey buildings can achieve significant reductions in EE and EC, making them a

more sustainable option for residential construction.

The study underscores the importance of considering building design and construction methods in reducing the

environmental footprint of residential buildings. Multi-storey designs, particularly those utilizing efficient

construction practices and materials, offer a promising pathway towards more sustainable construction. Future

research should continue to explore these design efficiencies and extend the analysis to other building types and

construction methods to further refine our understanding of the environmental benefits of different construction

approaches.

250.00

200.00

150.00

100.00

50.00

-

35.000

30.000

25.000

20.000

15.000

10.000

5.000

-

1-Storey Bungalow

2-Storey Bungalow

4-Storey Bungalow

Figure 12: Comparing EE and EC of structural components between 1, 2, and 3-storey bungalow.

Wall Systems

In building construction, wall systems play a crucial role in determining the structural integrity and thermal

performance of a building. Various materials can be used for wall systems, each contributing differently to the

EE and EC of the building. In this study, several materials for wall systems, including Ordinary Portland Cement

(OPC), clay bricks, and different generations of concrete mixes with varying percentages of fly ash: GEN 1

(15%), GEN 2 (15%), GEN 2 (30%), and GEN 3 (15%) were evaluated. The study examined wall thicknesses

of 100mm, 150mm, and 200mm. By changing the wall thickness with different material types, the EE and EC

values can be compared. This approach allows the study to identify the most sustainable combinations of

materials and thicknesses for different building types.

By referring to Figure 13, the analysis reveals that building height significantly influences the environmental

performance of wall systems, with multi-storey constructions showing notably lower EE and EC per square

meter compared to single-storey buildings. This trend highlights the substantial environmental benefits of

advanced construction methods like the IBS. The findings emphasize the importance of innovative construction

techniques and materials in reducing the environmental footprint of residential buildings.

Page 566

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

400.00

350.00

300.00

250.00

200.00

150.00

100.00

50.00

-

50.00

45.00

40.00

35.00

30.00

25.00

20.00

15.00

10.00

5.00

-

1-Storey Bungalow

2-Storey Bungalow

4-Storey Bungalow

Figure 13: Comparing EE and EC of wall systems between 1, 2, and 3-storey bungalow.

Roof Systems

The roof system of a building plays a crucial role in its overall structural integrity and environmental impact.

This study examined various materials and design options to evaluate their EE and EC values. The materials

considered included aluminium, stainless steel, section steel – ROW, and plywood. These materials were used

in two types of roof designs: gable roof and flat roof. To comprehensively compare the EE and EC values, the

roof types with different material types and sizes were analysed. The different roof types with varying materials

and sizes were compared to assess their EE and EC values.

Overall, from data given in Figure 14, the results indicate that the EE and EC of roof systems increase with the

building's complexity and height, as seen in the significant rise from the 1-storey to the 2-storey bungalow.

However, the 4-storey bungalow data suggests that advanced construction techniques can mitigate some

environmental impacts, resulting in a less dramatic increase in EE and EC. These findings underscore the need

to consider the environmental impacts of different building components when assessing construction methods'

sustainability. By understanding these variations, stakeholders can make informed decisions to optimize design

and material choices, promoting more sustainable construction practices.

350.00

300.00

250.00

200.00

150.00

100.00

50.00

-

25.00

20.00

15.00

10.00

5.00

-

1-Storey Bungalow

2-Storey Bungalow

4-Storey Bungalow

Figure 14: Comparing EE and EC of roof systems between 1, 2, and 3-storey bungalow.

Comparison of Total EE and EC Between 1-storey, 2-storey, and 4-Storey Bungalow

The evaluation of roof systems across different building sizes in terms of EE and EC reveals critical insights into

their environmental impacts. Figure 15 presents the total EE and EC values for 1-storey, 2-storey, and 4-storey

bungalows, highlighting notable differences across these structures.

Page 567

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

For a 1-storey bungalow, the roof system exhibits relatively high energy consumption and carbon emissions.

This is likely due to the larger roof surface area relative to the overall size of the building, along with the

substantial energy input and emissions generated by the chosen materials and construction techniques. In

contrast, the results for a 2-storey bungalow show a notable decrease in both energy consumption and carbon

emissions. This reduction is attributed to the increased efficiency inherent in multi-story building designs. The

shared structural components and reduced roof surface area per unit of floor space in taller buildings contribute

to this lower per-square-meter environmental impact. For the 4-storey bungalow, energy consumption and

carbon emissions slightly increase compared to the 2-storey bungalow yet remain lower than those of the 1-

storey bungalow. This indicates that while there are initial efficiency gains in the 2-storey structure, the benefits

may plateau or regress slightly due to the additional structural complexities and materials required for taller

buildings. Nonetheless, the 4-storey bungalow still benefits from shared structural elements and a reduced

relative roof surface area.

The comparison of these results underscores the importance of optimizing roof system design and materials to

minimize environmental impacts. Multi-story buildings generally perform better in terms of energy and

emissions per square meter, largely due to the more efficient use of materials and construction methods that

leverage shared structural components. However, the slight increase in energy and emissions for the 4-storey

bungalow suggests diminishing returns in savings as building height increases beyond a certain point.

Overall, these findings highlight the need for careful consideration of roof system designs in sustainable building

practices. The significant reductions in energy consumption and emissions achieved in multi-story bungalows

emphasize the potential for environmental benefits when optimizing building height and design. By leveraging

these efficiencies, the construction industry can make more informed decisions that contribute to reducing the

overall environmental footprint of residential buildings.

500,000.00

450,000.00

400,000.00

350,000.00

300,000.00

250,000.00

200,000.00

150,000.00

100,000.00

50,000.00

-

40,000.000

35,000.000

30,000.000

25,000.000

20,000.000

15,000.000

10,000.000

5,000.000

-

1-Storey Bungalow

2-Storey Bungalow

4-Storey Bungalow

Figure 15: Comparison of total EE and EC values between 1-storey, 2-storey, and 4-storey bungalow

CONCLUSION

In conclusion, this research aimed to investigate the EE and EC values of different building methods and

materials within the Malaysian construction industry. The primary focus was on comparing the CIS and IBS

methods to identify the most environmentally sustainable options.

The first objective was to examine the EE and EC values during the manufacturing phase of both CIS and IBS

methods. The analysis revealed that the IBS method consistently resulted in lower EE and EC values compared

to the CIS method across different building sizes. This can be attributed to the use of prefabricated components

in the IBS method, which are manufactured in controlled environments, leading to increased efficiency and

reduced material waste. These findings suggest that switching to IBS could significantly reduce the

environmental impact of residential construction. The second objective was to recommend the best option by

evaluating the environmental impact with a focus on minimizing EE and EC. The results indicated that even

when considering different building materials and component sizes, the IBS method still performed better in

Page 568

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

terms of lower EE and EC values. This reinforces the conclusion that the IBS method, due to its prefabrication

process, is a more sustainable choice for reducing the environmental footprint of building construction. The

results obtained from the two objectives highlight the importance of selecting appropriate building methods and

materials. The significant reduction in EE and EC values with the IBS method underscores its potential for

contributing to more sustainable construction practices. By adopting IBS, the Malaysian construction industry

can move towards more environmentally friendly practices, aligning with global sustainability goals and

reducing the overall carbon footprint of residential buildings. This research provides a clear recommendation for

the industry to consider the IBS method as a viable alternative to traditional CIS construction, promoting both

environmental and economic benefits.

To build upon the findings of this research, several recommendations for future work can be made. Firstly,

extending the scope of the study to include a broader range of building types and configurations would provide

a more comprehensive understanding of the environmental impacts associated with different construction

methods. This could involve analysing high-rise buildings, commercial structures, and industrial facilities to

assess whether the observed benefits of the IBS method apply universally across various building categories.

Secondly, future studies should consider the long-term performance and durability of materials used in both CIS

and IBS methods. Evaluating the lifecycle impacts, including maintenance, repair, and eventual disposal or

recycling of materials, would offer a more holistic view of the environmental benefits. This would help in

understanding not just the immediate EE and EC values but also the sustainability of the building methods over

their entire lifespan.

ACKNOWLEDGEMENT

I would like to express my deepest gratitude to my supervisor, Dr. Wan Mohd Sabki, for his invaluable guidance

and support throughout this research. I also extend my heartfelt thanks to my family members for their

unwavering encouragement and to my friends for their constant support. Their collective contributions have been

instrumental in the successful completion of this study.

REFERENCES

1. ISO 14040, ISO 14040: Environmental management - Life cycle assessment - Principles and framework

1997, International Organization for Standardization (ISO): Switzerland.

2. Delnavaz, M., et al., A comparative study on the environmental impact of cast in situ concrete and

industrialized building systems: a life cycle assessment approach. Environment, Development and

Sustainability, 2023: p. 1-19.

3. ISO14040, Environmental management - Life cycle assessment - Principles and framework 1997.

4. Haddad, A., et al., Characterising Embodied Energy in Construction Activities Using Energy Inventory

Life Cycle Assessment Method. Buildings, 2022. 13: p. 52.

5. Mohd Safaai, N.S., et al., Projection of CO2 Emissions in Malaysia. Environmental Progress &

Sustainable Energy, 2011. 30: p. 658-665.

6. Siti Halipah, I., et al., Embodied energy and CO2 analysis of industrialised building system (IBS) and

conventional building system. Journal of Advanced Research in Fluid Mechanics and Thermal Sciences,

2018. 51: p. 259-266.

7. Dixit, M.K., et al., Identification of parameters for embodied energy measurement: A literature review.

Energy and Buildings, 2010. 42(8): p. 1238-1247.

8. Omar, W.M.S.W., Development of hybrid life cycle inventories (HLCI) database for embodied energy

and carbon intensities of Malaysian construction materials. IOP Conference Series: Materials Science

and Engineering, 2019. 513: p. 012041.

9. Wyckoff, A.W. and J.M. Roop, The embodiment of carbon in imports of manufactured products:

Implications for international agreements on greenhouse gas emissions. Energy Policy, 1994. 22(3): p.

187-194.

10. A Short Guide to Embodied Carbon in Building Structures. The Institution of Structural Engineers, 2011.

11. Mohebbi, G., et al., The Role of Embodied Carbon Databases in the Accuracy of Life Cycle Assessment

(LCA) Calculations for the Embodied Carbon of Buildings. Sustainability, 2021. 13: p. 7988.

12. Lu, Z.-H. and W.M.S. Wan Omar, Environmental Impact Assessment of Tall Building Structural Design

Page 569

www.rsisinternational.org

INTERNATIONAL JOURNAL OF RESEARCH AND INNOVATION IN SOCIAL SCIENCE (IJRISS)

ISSN No. 2454-6186 | DOI: 10.47772/IJRISS | Volume IX Issue XII December 2025

with Precast Building System and Conventional Building System on Embodied Energy and Embodied

Carbon. Vol. 2157. 2019.

13. Wan Omar, W.M.S., et al., Assessment of the embodied carbon in precast concrete wall panels using a

hybrid life cycle assessment approach in Malaysia. Sustainable Cities and Society, 2014. 10: p. 101–111.

14. Abouhamad, M. and M. Abu-Hamd, Life Cycle Assessment Framework for Embodied Environmental

Impacts of Building Construction Systems. Sustainability, 2021. 13: p. 461.

15. Zhang, X., et al., Statistical characteristics and scenario analysis of embodied carbon emissions of multi-

story residential buildings in China. Sustainable Production and Consumption, 2024. 46: p. 629-640.

16. Zhao, Y., Y. Xu, and M. Yu, An approach for measuring and analyzing embodied carbon in the

construction industry chain based on emergy accounting. Ecological Indicators, 2024. 158: p. 111481.

17. Basbagill, J., et al., Application of life-cycle assessment to early stage building design for reduced

embodied environmental impacts. Building and Environment, 2013. 60: p. 81–92.

18. Zaini, N., et al., A Review of Embodied Energy (EM) Analysis of Industrialised Building System (IBS).

Journal of Materials and Environmental Science, 2016. 7: p. 1357-1365.

19. Helal, J., A. Stephan, and R. Crawford, Integrating embodied greenhouse gas emissions assessment into

the structural design of tall buildings: A framework and software tool for design decision-making. Energy

and Buildings, 2023. 297: p. 113462.

20. Khasreen, M., P. Banfill, and G. Menzies, Life-Cycle Assessment and the Environmental Impact of

Buildings: A Review. Sustainability, 2009. 1.

21. Zabalza Bribián, I., A. Aranda Usón, and S. Scarpellini, Life cycle assessment in buildings: State-of-the-

art and simplified LCA methodology as a complement for building certification. Building and

Environment, 2009. 44(12): p. 2510-2520.

22. Hui, S.C.M. and T. Ma, Analysis of environmental performance of indoor living walls using embodied

energy and carbon. International Journal of Low-Carbon Technologies, 2016. 12.

23. Blengini, G.A. and T. Di Carlo, The changing role of life cycle phases, subsystems and materials in the

LCA of low energy buildings. Energy and Buildings, 2010. 42(6): p. 869-880.

24. Wan Omar, W.M.S., A Hybrid Life Cycle Assessment of Embodied Energy and Carbon Emissions from

Conventional and Industrialised Building Systems in Malaysia. Energy and Buildings, 2018. 167.

25. Zhang, X., et al., Predictive models of embodied carbon emissions in building design phases: Machine

learning approaches based on residential buildings in China. Building and Environment, 2024. 258: p.

111595.

26. Xiang, Y., et al., Design optimisation towards lower embodied carbon of prefabricated buildings:

Balancing standardisation and customisation. Developments in the Built Environment, 2024. 18: p.

100413.

27. ISO_14044, Environmental management — Life cycle assessment — Requirements and guidelines.

2006.

28. SAIC, et al., Life-cycle assessment: principles and practice, 2006, National Risk Management Research

Laboratory, Office of Research and ….

29. SAIC, Life Cycle Assessment: Principles and Practice. 2006. 3-15.

30. Babu, B.V., Life Cycle Inventory Analysis (LCIA). 2006.

31. Thibodeau, C., A. Bataille, and M. Sié, Building rehabilitation life cycle assessment methodology–state

of the art. Renewable and Sustainable Energy Reviews, 2019. 103: p. 408-422.

Page 570

www.rsisinternational.org