Comparative Cost Analysis Between Hydraform Interlocking Brick and Sandcrete Block as Walling Materials for Low-Cost Housing Development in Nigeria

This study analyzed the cost of production and construction of 225mm hollow sandcrete blocks and hydraform interlocking bricks and walls to compare the findings of the results. The study was conducted in Auchi, Estako West Local Government Area of Edo State, Nigeria. The study compared the construction of two models of 225mm hollow sandcrete blocks and hydraform interlocking bricks, materials employed for wall construction for the study are; clay, cement, sand, water and mould. The result of the study indicates that unit cost of 225mm hollow sandcrete block and hydraform interlocking bricks are ₦168.57 and ₦57.85 respectively. While the cost per square metre of 225mm hollow sandcrete block wall and hydraform interlocking brick wall are ₦3,199.40 and ₦3,079.52 respectively. The study also revealed that it is more costly to apply finishes to sandcrete block wall when compared with hydraform interlocking brick wall. Sandcrete block wall requires rendering or plastering to both faces of the walls, while hyraform interlocking wall requires rendering of not more than 300mm girth to vertical external corners of the brick wall. The study, therefore, recommends the use of hydraform interlocking bricks for low-cost housing to reduce the housing deficit in Nigeria. Keywords : Sandcrete block; hydraform interlocking brick; walling; cost analysis; Auchi; DOI: 10.7176/JNSR/11-22-07 Publication date: November 30 th 2020


Cost Analyses of 225mm Sandcrete Block Wall Construction and Hydra Form Interlocking Brick Wall Construction. 3.1 Built-Up Rates for Block Works
225mm sandcrete hollow block wall laid with cement and sand mortar (1:4) in stretcher bond…………. m 2 i Block Production Mix Ratio = 1:14 This translates to one bag of ordinary Portland cement to twenty-eight head pans of sand, since there are two head pans in a bag of cement. The cost of one bag of ordinary Portland cement is ₦2,500 as at the time of carrying out the research. 28

Cost Analyses
The above results show the various cost for the production of 225mm hollow sandcrete blocks alongside the cost of producing hydra form interlocking cement stabilized bricks. At the time of the research, the cost for the production of a unit of the block was ₦168.57, while the cost of producing a unit of hydra from interlocking cement stabilized bricks, on the other hand, was ₦57.85. In constructing hydra form interlocking bricks wall, apart from the base mortar that requires a thin layer of mortar to link the first course to the floor, no mortar is required for the subsequent courses of the hydra from interlocking walling system. The absence of mortar bedding and jointing in the hydra form interlocking brick walling process led to a significant reduction in the quantity of mortar used compared to the case of the sandcrete block. The total cost for constructing one metre square of sandcrete block wall was ₦3,199.40 inclusive of material and labour. While that of the hydra form of the interlocking brick wall was ₦3,079.52.
The results revealed that it is more costly to apply finishes to sandcrete block wall when compared with hydra form of an interlocking brick wall.Sandcrete block wall requires rendering or plastering which include the application of a smooth coat of material to walls to provide a joint-less, hygienic, easily decorated smooth finish to walls as well as to covers up the unevenness in the block wall. While on the other hand, hydra form interlocking bricks wall do not require rendering or plastering thereby resulting in significant cost savings on plastering. Painting can be applied to both sandcrete block wall and brick wall; however, hydra form interlocking blocks are also aesthetically pleasing and may not require painting. It is therefore recommended for affordable low-cost mass housing development.

Conclusion
The following conclusions can be drawn from the results of cost analyses of hollow sandcrete block and hydra form interlocking brick wall as experimented: i. Hydra form interlocking brick wall construction significantly reduces non-value-adding steps when Journal of Natural Sciences Research www.iiste.org ISSN 2224-3186 (Paper) ISSN 2225-0921 (Online) Vol. 11, No.22, 2020 37 compared with the conventional sandcrete block wall construction. ii.
Interlocking brick wall construction eliminates the cycle time of block bonding thus increasing the speed of wall construction for interlocking blocks. iii.
Hydra form interlocking blocks are affordable in terms of cost. There is also a significant reduction in the material required for the interlocking block wall construction process due to the absence of mortar jointing. iv.
Reduction in the labour and material requirements in the hydra form interlocking block wall construction makes the cost associated with the process of building walls using the interlocking blocks less expensive. v.
The cost of applying basic wall finishing to hydra form interlocking brick wall construction is significantly cheaper when compared with sandcrete block wall construction. Hydra form interlocking brick wall does not require plastering to both faces of the wall, thereby resulting in cost savings for plastering to the wall.

Recommendations
The study, therefore, recommends the following: i. The use of hydraform interlocking bricks for the production of low-cost to reduce the housing deficits in Nigeria. ii.
The government should provide affordable mass housing schemes using hydraform interlocking bricks for her low-income earners through mortgage arrangement. iii.
Stakeholders in the construction industry should commercialize the technology for the production of hydraform interlocking bricks walling system in Nigeria. Future researches are encouraged in the areas of: i. Comparative analysis of sandcrete block wall and hydra form interlocking bricks concerning functionality. ii.
Performance of the two (2) walling materials in different atmospheric conditions.