Techniques and Materials for Low-Cost Housing Construction at Reduced Cost
TEASER: There is this old wives’ tale about low cost housing, which believes that low cost housing is suitable for only substandard works and are constructed by making use of cheap building materials of low quality. Is this a truth or misconception??
Housing is universally considered as the second most important basic need of man after food. Its impact on the health, welfare and output of man cannot be underemphasized. For example, having a good house to return to after the day’s work brings a certain comfort. Thus, housing plays a vital role in a person’s standard of living and place in the society. In fact, affordable and decent housing is a basic right for everybody because without stable shelter, everything else falls apart.
However, there’s housing deficit and/or crises all over the world with a massive shortage of homes for expanding populations. According to a survey conducted by the United Nations in 2005, about 1.6 billion people live in substandard housing and 100 million are homeless. Unfortunately, those figures would likely be double now.
Over the years, different housing policies and programmes to treat housing problems have been tried, however, most of these policies and programmes have struggled to provide lasting solutions. To this end, low cost housing might just prove to be the lasting solution that our housing problem needs.
Low Cost Housing
Low Cost Housing is a new concept which deals with effective budgeting and following of techniques which help in reducing the cost of construction through the use of locally available materials and eco-friendly recycled materials along with improved skills and technology without sacrificing the strength, performance and life of the structure.
There is this old wives’ tale about low cost housing, which believes that low cost housing is suitable for only substandard works and are constructed by making use of cheap building materials of low quality. Arguably, this belief is totally a misconception as low cost housing is done by proper planning and management of resources, among others.
The Roles of Professionals in the Construction Industry
Globally, providing affordable, decent, quality and attractive housing is usually seen as the responsibility of the government. In fact, our governments have to produce affordable housing — they have to produce answers. It is their core responsibility to develop infrastructures to create an atmosphere for economical development. Thankfully, at the forefront of infrastructural development is the professionals in the construction industry, particularly civil engineers.
Civil engineers, in collaboration with other professionals, are tasked with the responsibilities of planning, designing, building, supervising, operating and maintaining infrastructural projects and systems in public and private systems. Therefore, to achieve the goal of constructing houses at the lowest possible cost, they might have to start looking away from the construction techniques and materials we currently employ in order to truly make housing affordable for everyone, particularly for minimum wage earners. Other important considerations include space management, efficient planning and project management, economical construction technologies, alternative construction methods, and right choice of construction materials though proper consideration for natural factors while choosing these materials.
Minimum Standards
In the construction industry, common specifications, methods and procedures are very important to ensure greater reliability and consistency in terms of the quality, compatibility and compliance in the construction of buildings. Hence, there are minimum requirements for standard accommodation.
It is clearly visible that the cost of construction of a building is directly proportional to the area covered. In low cost housing, economy in construction is an extremely important factor, but one should not lose sight of the fact that any economies effected are not worth it, if the minimum requirements of the basic physical comfort in the dwellings are not met. In order to meet these twin requirements of economy and comfort, one has to depend, to the maximum extent, on cost effective construction technology to provide minimum standard accommodation.
Taking Nigeria as a case study, the current national building code and housing standards across the states of Nigeria adopts the following (among others) minimum standards:
1. Living room — 15 sq.m
2. Bedroom — 13.6 sq.m
3. Kitchen — 6 sq.m
4. Dinning — 7.5 sq.m
5. Store — 1.5 sq.m
In spite of the Nigerian government adopting the above minimum requirements, researchers have shown that the existing housing standards are not realistic and the low-income urban dwellers (who barely eat three square meals a day) cannot afford the conventional standard houses because of their poverty level, as it requires high construction cost, building material and labour.
In fact, case can be made that the above standard shows a complete adoption from the developed nations especially Britain which is not practicable here in Nigeria and other developing nations of the world. Hence, the reason why it is difficult or almost impossible for the poor to observe and comply with the established standard.
Cost Effective Construction Techniques and Materials
In any construction project, building materials form one of the main items of expenditure and can make or break a construction budget. Hence, materials with the lowest cost implications should be given priority. But again, the construction technique and quality of construction materials should not be compromised just for lowering the cost, as this can cost a project irreversible damages in the future.
In lieu of extensive research and development works that have taken place at various research centres to use local materials, waste materials and prefabricated structural components to reduce the cost of construction, the following are some of the improved cost effective techniques that could be used in building projects:
1. Foundation: Under-reamed piles for foundations have been developed for housing in black cotton soil area. Also, the depth of a building foundation is usually 0.9 – 1.2m deep in the soil, but this can be altered to around 0.6m in depth for typical soils. Adopting this can save a lot of time and total foundation costs, but in other delicate or soft soils, the cost reduction objective may not be fully attained or executed correctly.
2. Damp Proof Courses: Use of polythene, bituminous materials and cement mortar with water proofing agents have been suggested for damp proof courses.
3. Walls: Soil-cement blocks, fly ash bricks, precast hollow concrete blocks (without plaster), brick panels and precast wall panels may be used to get reasonably good comfort with little cost.
4. Doors and Windows: Precast R.C.C. frames can save 25 to 30% cost when composed with wooden frames. Instead of wooden shutters particle board shutters may be used.
5. Lintels: Locally available stones and slates can serve as lintels.
6. Precast Structural Elements: In mass constructions works, precast members may be used for columns, beams, reapers and staircases. One can think of using wall panels too.
7. Roof Units: A.C. sheets, cement bonded fibre sheets, paper corrugated sheets, lime and fly ash cellular slabs, solid planks, slates, ferrocement roof units etc. may be used for low cost housing roofs.
8. Flooring: Low cost housing flooring may be with soil cement base, thin clay tiles, bricks on edges or with flagstones.
9. Load-bearing Structures: When it comes to defining the structure of a house, the arrangement should preferably be a load-bearing one. This is primarily because it is more economical, easy to construct, and flexible when compared to framed structures.
10. Architectural Drawings: One of the things that add up the extra cost to a building project is a fuzzy plan that is full of curves and complexities. Since plans represent a very large part of construction costs, it is necessary to observe with continuous attention. Thus, every single detail and complexity of the plan, and cost of construction should be evaluated.
11. Maintenance Cost: In buildings, maintenance costs should be kept low as much as possible since it defeats the purpose of standard yet affordable housing if major renovation expenses are incurred as soon as possible.
12. Choice of Materials: Materials found within the locality of the construction should be given priority for selection and use in an innovative form in order to minimize transportation costs. Materials that can be manufactured or recycled from wastes in an energy efficient method should also be considered. Materials used should be easily recyclable and reusable on other building projects.
13. Shipping Containers: Recent developments point to Cargotecture (that is, building houses using shipping containers) as a viable low-cost housing method for fixing the gap in housing that the world experiences today. The ISO shipping containers are a good fit with the guidelines listed and a cheaper alternative to the conventional sandcrete or concrete block structures. In addition, they are mobile and require little construction time, though there is till the problem of managing how heat and humidity affect the metal material that the containers are made of.
14. Modular Buildings: One of the innovative and cost-effective solutions to the global housing crises lies in modular homes. Modular buildings consist of prefabricated sections that can be made of steel, concrete (preferably lightweight for large building projects) or timber. Using these materials make modular homes energy efficient, while the flexibility of their design allows them to be moved, making them a quick and sustainable solution for emergency accommodation.
The suggestions above for achieving low cost housing is widespread and varies depending on the nature and geographical location of the proposed building, construction budget, availability of construction materials, good construction planning and management practices, among others.
Truly, low-cost houses are those which are affordable not just in name but can actually be financed by low-income earners. However, it is necessary that good planning and design methods are adopted by utilizing the services of an experienced engineer or architect for supervising construction work, thereby achieving overall cost effectiveness to the extent of 20-25% in actual practice.
References
[1] Federal Government of Nigeria (FGN). National Building Code. Federal Ministry of Housing and Urban Development, Abuja; 2006.
[2] Federal Government of Nigeria (FGN). National Housing Policy for Nigeria. Federal Ministry of Housing and Urban Development, Abuja; 2012.
[3] Basic Civil Engineering — S.S. Bhavikatti
[4] Atamewan, E. E and Olagunju, R. E. (2017). “Sustainable Low-Income Housing and Practicable Minimum Design Standards in Bayelsa State, Nigeria.” Journal of Sustainable Architecture and Civil Engineering (JSACE). http://dx.doi.org/10.5755/j01.sace.20.3.18208
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