technology is the key to mass housing in nigeria … is the key to mass...1 technology is the key to...
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Technology is the Key to Mass Housing in Nigeria
The main construction methodology for housing in Nigeria, particularly in the urban areas, is still concrete / sandcrete masonry block. It is pertinent to note that except those made by the largest construction companies; most concrete/ sandcrete block used in housing construction in Nigeria is not manufactured with reference to any standard specification for good quality work.
Mobile Egg Laying Concrete Block Machine
Despite the prevalence of concrete / sandcrete block system in Nigeria a few innovative contractors / developers have begun to explore monolithic concrete construction as an alternative building methodology for housing. Structuracasa is one of the few with its proprietary Aluma EasySet modular formwork system of construction.
Bungalow units under construction at Legacy Estates using Aluma EasySet construction system.
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CONCRETE / SANDCRETE BLOCK SYSTEM ANALYSIS
ATTRIBUTE PRO CON
Raw materials readily available:
Cement, Sand and Water for blocks.
Timber for form work.
Granite aggregate for concrete.
Steel reinforcement for concrete.
Adaptable components for house finishing suitable for system.
Most materials readily available and supply are becoming more stable with increased domestic production capacity especially for cement.
Single level houses can be built with relatively very low content of steel reinforcement.
Negatives of this construction system include waste, especially of timber products used for formwork, shuttering and scaffolding and the lack of standards in most of the naturally occurring inputs.
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Low technology requirements:
Hand casting of blocks.
Manual mixing of concrete.
Hand bending of steel reinforcement.
Basic tools required.
Blocks can be locally manufactured on any construction site.
Wide range of tolerances acceptable allowing variation in specifications.
Locally made blocks typically substandard and not suitable for load bearing structures hence a lot of steel (and added cost) required for multi‐story buildings.
Scalable:
Labor intensive multiple construction crews.
Labor intensive Intermediate technologies for casting of blocks.
Small machine mixing of concrete.
Industrial production of aggregate.
Small contractors and even owner builders can afford to manufacture the blocks while larger companies can automate, increasing efficiency and quality of products.
Industrial production of blocks in controlled factory environment for retail and wholesale distribution not available due to cost of operations, product price and transportation.
Lack of enforceable standards hinder further development of concrete masonry industry.
Labor familiarity:
Local labor – masons, carpenters etc.
Low use of automated machine tools.
Minimal educational requirements.
On the job apprenticeship.
Most construction workers in Nigeria have a basic understanding of CMU construction using concrete /sand concrete blocks and concrete frame construction.
Opportunity exists to upgrade worker skills through formal training programs.
Very few formally trained masons available in Nigeria. Semi‐skilled masons with training imported from neighboring countries despite unemployment in Nigeria.
Only large foreign owned companies run comprehensive training and apprenticeship programs to develop tradesmen.
Semi industrial application:
Factory scale blocks production feasible.
Mostly used by large foreign firms producing for their own projects.
Distribution and transportationof finished expensive.
Market price of finished industrially produced concrete blocks too high for mass market.
No viable concrete masonry block industrial manufacturing infrastructure exists in Nigeria compared with South Africa.
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Below is an overview of the characteristics of the prevalent masonry block construction systems utilized for over 98% of new housing construction in Nigeria.
In an effort to address a lot of the issues discussed above pertaining to the use conventional masonry block construction for mass housing in Nigeria, Structuracasa has introduced a new way to build large scale housing estates with monolithic cast in situ concrete utilizing aluminum formwork that is reusable multiple times. The Aluma EasySet construction technology provides the critical advantages as follows;
Cost
o Economies of scale and scope as well as value engineering involved in an industrialized, yet simple, construction process yield cost savings on an average concrete carcass of anywhere between 10 and 20% depending on project size
Time
o Speed of construction to finish is greatly increased due to the system approach to construction and several sub attributed of the Aluma EasySet system such as the post head system that allows decking panels to be struck in as little as 3 days after casting suspended deck slabs
Quality
o The quality and uniformity of the shell / carcass structure obtained using the Aluma EasySet system helps to force a consistent quality across projects and reduces re work and additional finishing processes to obtain a high quality product
Durability of finished structures:
Long lasting and weather resistant.
Compared with adobe or compressed earth blocks this system provides durable housing structures.
Quality of finished structures varies widely depending on the skill level of tradesmen and % of cement used in making blocks.
Skill and Training:
Low skill and training levels required.
No shortage of labor due to lowbarrier of entry into trades through informal apprenticeship programs with older trades people.
Despite the low skill requirements most masons do not have the requisite training in accordance with technical educational / trade standards such as City & Guilds.
Low / medium level of precision required:
Does not require advanced tools or high skill workers for basic production and functionality.
Mistakes are usually covered up during plastering stages.
Mechanical and electrical lines are typically chiseled in after block work frame is completed.
No concerted effort to formalize industry and increase quality of production because current output is acceptable.
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In the table below, a comparison is made to highlight the differences between the Conventional Sand Crete Block Construction and the Solid Concrete Construction:
CONVENTIONAL BLOCK WORK CONCRETE
1 Solid, but not as strong as concrete. Has a tendency to crack and dimension precisions is lacking.
Solid reinforced, stronger, longer lasting structure with much lower risk of collapse or cracking.Consistent reliable finish, house after house, with precise dimensions and straight walls.
2 Plastering is needed hence more expensive as the cost of Labor is included. More materials are used
Allows for easy and accurate standardization and installation of finish parts.Lower material and labor cost is not needed.
Reduces material wastage.
3 Houses are built at a slower pace as more manpower is used rather than technology.
Developer spends more due to the time consumption involved in Block molding, Laying, Plastering etc.
Allows large number of units to be built in any given cycle .The result is 1. Faster delivery to project owner / sponsor2. Lower financing cost for developer / owner due to time savings
4 Delivery Schedule and Quality Assurance is not reliable as man power is more involved.
Reliable delivery schedule of completed shell units to client. Consistent quality control processes resulting in very little variability in end product thus saving client expense of rework or dissatisfaction from consumers