1. Introduction
Housing construction has developed in a remarkable way over the years. The desire for the welfare of the future generations is important [
1]. With the purpose of easing pressure of improving housing provision across the globe, the integration of both sustainability and affordability was therefore considered as the potential approach towards housing provision [
2]. This approach is referred to as sustainable affordable housing. Sustainable affordable housing is described as housing which satisfies the demand and needs of the present generation without compromising future generations’ ability to meet their housing demands [
3,
4,
5]. Alternatively, sustainable affordable housing can be defined simply as housing that is better planned and constructed, more durable, safe, significantly affordable, inexpensive to maintain, and has strong and inter-related economic, social and environmental components [
6,
7]. Appropriate, accessible, and sustainable housing is indispensable and it remains a basic need to the people. Thus, it needs to be available, affordable and durable continuously in the built environment [
8].
Notwithstanding, to sustain the provision of affordable housing across South Africa, the housing construction industry should be more concerned about the economical handling of building materials cost. Building material or construction material is any material that can be used for the construction housing projects. It commonly includes steel, copper, cement, bitumen, lumber, masonry bricks/blocks, and sand among many others. The housing construction industry is one of the most important industries that underpins the economic development of a nation [
9]. The construction sector impacts socio-economic expansion development in the developing countries by contributing substantially to their gross domestic product (GDP) [
10,
11]. As a result of this, it is crucial for the sector to understand the impact of the building materials cost in completing housing projects as scheduled. Building materials cost can actually comprise half (50%) of the total cost of all projects executed by a construction industry [
12]. Moreover, building materials cost depends on supply and demand, as well being affected by quality, quantity, time, place, buyer, and seller during a construction production [
13]. Other factors are currency exchange, material specification, inflation pressure, and availability of new materials in the country [
14]. Generally, total cost of executing a housing project is hugely affected by improper material handling on the construction site, and all this impacts the quality and time scheduled for a project to be completed [
15]. Durdyev and Hosseini [
16] conducted a survey and systematically reviewed studies on construction project delay; this revealed that the ten most common causes of this are climatic conditions, ineffective communication, deficiency in coordination and conflicts between stakeholders, improper planning, material shortages, financial problems, payment delays, equipment/plant shortage, lack required experience among project stakeholders, labour shortages, and poor site management.
According to some researchers, building materials play a pivotal role in building as a substantial input in the project development [
17]. In South Africa, the incessant rising in price of building materials is a huge challenge towards the performance of the construction industry in delivering projects with quality and within the time scheduled [
18]. The fluctuating market value for building materials tends to cause high project risk to all stakeholders (suppliers, contractors, and clients) involved in the construction production [
19,
20,
21]. The demand for housing of all types, coupled with inflation and tight monetary supply, has caused a big challenge to the cost of building materials in the construction industry [
22]. Therefore, an improved sustainable housing delivery within the budgeted time, cost, and expected quality, as well taking into consideration the stakeholders’ satisfaction and cost of building materials, is absolutely essential. Sustainability is generally elaborated as a development that satisfies the needs of the current generation, without compromising future generations [
2]. Therefore, to achieve the UN Sustainable Development goal, there is the need for a significant reduction in the cost of construction. As building materials contribute up to 50% of the cost of construction, there is a need to consider the factors which will minimise the excess cost of building materials
Table 1 revealed variation in the construction material price index in South Africa between 2010 to 2018. These percentage increases are in line with overall inflation, as measured by the price index. Additionally, the survey of [
18] revealed a diverse trend in the cost of building materials over the past two decades in South Africa (2001–2011). It appeared that the cost of building materials increased consistently yearly. Considering this, it is necessary to evaluate the effects of upsurge in the price of building materials on the delivery of affordable housing in South Africa.
3. Research Methodology
To achieve the objective of this study, the sequential mixed methods approach posited by Teddie and Tashakkori [
45] and Östlund et al. [
46] were used. The process of the sequential mixed methods approach used is presented in
Figure 1.
The cluster sampling method was used for data collection to redistribute the target population (with a high concentration of construction companies and experienced professionals) into smaller groups (clusters). These samples are randomly selected for data collection and result generalization. As such, construction managers, project managers, sales consultants, contractors, quantity surveyors, site managers, architects, and site engineers were involved. Questionnaires for the quantitative data were self-administered to guide and obtain opinions of the selected respondents.
After distributing the questionnaires, interviews were scheduled with construction industry professionals. The basic purpose of the interviews was to consolidate the questionnaire in acquiring relevant data for the purpose of the study. A total of 137 questionnaires were administered in person to construction stakeholders (architects, site engineers, project managers, quantity surveyors, contractors, building materials suppliers, site managers, and government workers) in the Western Cape Province. A total of 69 questionnaires were recovered and used for analysis. Quantitative data were analysed with the use of Statistical Package for Social Sciences (SPSS). A four-point Likert scale ranging from 1 (not at all) to 4 (to a very large extent) was adopted to capture the effects of the increase in the cost of building materials on housing delivery.
3.1. Profile of Respondents
Table 2 presents the positions held by survey participants. The largest groups of respondents (20.3%) were project managers; quantity surveyors represented 17.4%; site engineers, 11.6%; construction managers, 13%; 11.6%, sales consultants; contractors, 7.2%; site managers, 5.8%; and architects, 13%. In essence, the
Table 2 data distribution indicates that the highest number of participations consisted of both quantity surveyors and project managers. Other respondents, such as construction managers, architects, sales consultants, and site engineers, also demonstrated participation, although in fewer quantities. This effect was achieved due to availability-based on time scheduling.
Likewise, the views of many construction professionals in the South African construction industry will improve the result consistency. The years of involvement of respondents in the industry are considerably adequate to achieve the purpose of the study. According to the figures arrayed in
Table 3, 83% of the respondents have over 10 years of work experience in the construction industry. However, this does not indicate that the contribution and experiences of the respondents within 1–5 years is not relevant in this study.
In
Table 4, 23 factors were considered and carefully evaluated in understanding the effects of the increase in the cost of building materials on housing delivery. The array of the factors in the table is in descending order of the mean values (MVs); that is, from the highest order of MVs to the lowest order of MVs. From the order of the MVs with 69 respondents, it was observed that only the last six factors exhibited MVs below 3.00, while others were within the MVs of 3.26−3.01. This array demonstrates that some factors have high impacts more than other factors, irrespective of their standard deviation (SD) values calculated. For instances, factors such as “fluctuation in cost of construction” (ranked 1, MV = 3.26) and “high maintenance cost due to poor workmanship” (ranked 2, MV = 3.23) are extremely affected by the increase in the cost of building materials on housing delivery as indicated by respondents. This means that increase in the cost of building materials caused fluctuation in the cost of construction and high maintenance cost due to poor workmanship.
Additionally, some respondents indicated that increase in the cost of building materials caused “increase in cost of repair due to inferior materials used (ranked 3, MV = 3.19)”, including poor workmanship (ranked 4, MV = 3.14), client expectation’s quality project delivery (ranked 5, MV = 3.11), collapse of building due to less quality materials (ranked 6, MV = 3.10), conflict between client and contractors due to upward review of contract sum (ranked 7, MV = 3.10), delay in progress of project works (ranked 8, MV = 3.10), and other factors within 3.00. On the other hand, some respondents indicated that factors below MV of 3.00 are fairly affected by increase in the cost of building materials.
3.2. Analysis and Findings from Qualitative Studies
Analysis of qualitative data across individual cases was conducted to evaluate the effects of increase in the cost of building materials on the delivery of affordable housing. Qualitative case study interviews were conducted with three selected housing developers and construction organisations in South Africa. Purposive sampling, as posited by [
47,
48], was used in determining information-rich participants whose understanding is important for the study. These interviews were transcribed and analysed using content analysis.
Table 4 shows demographic of the respondents.
3.2.1. Case Study 1
Perception regarding the effects of increase in the cost of building materials on the delivery of affordable housing. The respondent, site supervisor emphasised that:
From experience, a common effect of increase in the cost of building materials is fluctuation; that is, in the sense that when material prices are not stable due to inflation, the contract or construction sum fluctuates, thereby affecting timely housing delivery to the populace. Conflict between client and contractor is also an effect of increase in the cost of building materials. Increase in the contract sum easily leads to disputes between involved stakeholders, leaving some disgruntled and dissatisfied.
The respondent pointed out relevant measures that can be taken into consideration to enhance sustainable housing delivery by advising South African government to ensure stable and viable regulations of the cost of building materials.
3.2.2. Case Study 2
Perception of project manager regarding the effects of increase in the cost of building materials on the delivery of affordable housing. The respondent stated that:
In my own opinion and experience in the construction industry, effects of increase in the cost of building materials are construction cost escalation, final cost production higher than budgeted and poor workmanship which in turn leads to high maintenance and repair cost. The respondent further stated that an increase in the cost of building materials has an adverse effect on client expectation of quality project delivery. In order to avoid conflict between clients and contractors, some contractors use substandard quality materials to meet the client budget requirement, and in this manner impact the client expectations of quality.
The project manager advised that the use of sustainable locally made building materials, rather than sophisticated building materials and techniques that are costly and energy consuming, should be encouraged by the government, as this will enhance affordable housing delivery. This will make the material cost effective and produce sustainable housing provisions.
3.2.3. Case Study 3
Perception of site manager regarding the effects of increase in the cost of building materials on the delivery of affordable housing. The respondent stressed that:
Increase in the cost of building materials has a massive effect on the timely delivery of housing. Building materials consume up to 60.0% of all construction costs. He further stated that increase in the cost of building materials will push the cost of construction higher than estimated project cost. Another effect, with my experience in the industry, is conflict between client and contractor due to the increase in project budgeted cost and delay in the progress of project works. The respondent further noted that late delivery of materials to site is the major cause of construction cost and time overrun.
The respondent suggested that in order to enhance sustainable housing delivery, some steps needs to be established. The availability of materials on site is very important, as this determines the speed at which the work is completed and will reduce materials wastage and cost towards economic sustainability.
Table 5 shows the summary of findings of qualitative interviews.
4. Discussion of Findings
The findings on the effect on housing delivery are discussed.
Table 3 and
Table 4 provided numerical results of respondents’ perceptions on the effects of increase in the cost of building materials on housing delivery. The findings reveal that the increase in the cost of building materials frustrates the progress of the construction industry in South Africa due to many affected factors, such as fluctuation in cost of construction, high maintenance cost due to poor workmanship, increase in the cost of repair due to inferior materials used, poor workmanship, and many others, as arrayed in
Table 6. From the tabularised results, it is observed that “fluctuation in cost of construction” with a MV of 3.26 is the most affected. The client and project contractors have been facing serious issues to maintain steady cost projection on construction projects [
17]. Therefore, cost control during the construction process is very important to ensure the success of a project [
49]. Further findings indicated that high maintenance cost due to poor workmanship, increase in the cost of repair due to inferior materials used, poor workmanship, client expectation’s on quality project delivery, and building collapses due to the use of less quality materials are all affected by increase in cost of building materials on housing delivery. Iwaro and Mwasha [
36] highlighted that workmanship plays an important role in project’s quality. One of the characteristics of a developed construction industry is in the output of quality buildings and structures [
50]. However, Oyedele and Tham [
51] posited that a lack of significant consideration for design constructability may cause building collapse during the construction process. Therefore, stakeholders’ satisfaction and timely project completion has been a yardstick for measuring project success in relation to time, quality, scope and cost [
52,
53].
5. Conclusions and Recommendations
Based on the findings from the study, it was understood that fluctuation in the cost of construction is a huge influence caused by increase in the cost of building materials on the delivery of affordable housing in Western Cape. The findings also revealed high maintenance cost due to poor workmanship and an increase in the cost of repair due to inferior materials used as other huge influences caused by the increase in the cost of building materials on housing delivery in Western Cape Province of South Africa.
With the purpose of guiding against excessive fluctuation in the cost of construction, stakeholders should have a well-developed plan for materials in advance to avoid the effect of the increase in building material prices in the market. Thus, proper planning and scheduling at the initial stages of construction are very essential, which includes the early purchase of building materials within the budgeted cost and suitable storage of building materials is to be adopted to avoid cost overrun, disputes, and inflation. If this could be the effect, it will enhance the timely delivery of housing at the budgeted cost specified and meeting client expectations. Affordable housing programs should also consider the economic sustainability of developers (e.g., the cost effectiveness of the projects) to ensure that these programs can be developed on a continuous basis, while developers can adopt cost reduction strategies (such as the use of regionally available materials and techniques), providing stable financial incentives is needed for developers to secure financial viability [
54]. El-hadj et al. [
55] revealed that value of architecture that is often ignored in the conception of affordable housing development project design can be enhanced. An enhanced architectural design can lower construction costs significantly, not only by reducing the quantity of material used, but also by minimising material waste. However, this could be achieved by limiting the number of corners or reducing the number of convex or concave corners reduces construction costs.