Author: A4KENYA

AMOUNT OF CEMENT USED IN AN AVERAGE 3 BEDROOMED HOUSE IN KENYA.

Cement cost takes an average of 35% of the total cost of construction of an average house basing on a low cost finish overall estimate of KES 20,000per m2. This is approximately KES 7,000 per m2.

The amount of cement used in total for an average 3 bedroomed residential house of 100m2 in plinth area is 958 bags at a cost of KES 691,000 basing on a price of KES 720 per 50kg bag.

A square meter of building in Kenya will use 9.6 bags.

2 BEDROOMED FLAT.

The average 2 bedroomed house in a middle class area such as Ruaka, Rongai, Kitengela, Ruai is approximately 60m2 in plinth area. This translates to 60m2 x 9.6bags=546bags costing KES 414,000.

A block of 2 bedroomed flats in the middle class neighborhoods standing on a 1/8th acre can contain 20 units. This means the total cement used will be 20 units x 546bags per unit=10,920 bags costing 7,800,000 KES.

SHOPS AND SINGLE ROOMS 1Oft by 10ft.

The average 10ft by 10ft room used as a shop or single room residence is approximately 10m2 in plinth area. This translates to 10m2 x 9.6bags=96bags of cement costing KES 69,100.

The breakdown is as below.

Foundation.

WALLING. Ratio of 1.4

BEAMS AND COLLUMNS. Ratio 1.2.4

FLOOR PLASTER. Ratio 1.3

WALL PLASTER. Ratio 1.4

EXTERNAL KEYING. Ratio 1.4

ACTUAL SITUATION ON THE GROUND.

In most small scale residential projects, the house owners usually rely on the local Fundi expertise on the mix ratio of cement. The usual tools used to measure the volumes are spades, wheel barrows and 20 liter water buckets.

8 wheelbarrow of sand/ballast make 1 tonne.

Four wheelbarrows are used to mix 1 bag of cement to 8 bags of ballast.

I bag of cement has 0.035 cubic meters in volume.

1 wheelbarrow has the below volume.

Assuming sand has a density of 1600kg/m3 and 8 wheelbarrows make 1 tone, 1 wheelbarrow has 1000/8=125kg.

1 wheelbarrow of sand has 0.08 Cubic meters in volume.

This sand volume per wheel barrow when compared to cement volume per bag gives a ratio of 1 cement volume to 2 sand volumes.

LOCAL FUNDI MIX.

The usual mix used by local fundis of 1 bag cement to 4 bags sand is actually 1 cubic meter cement to 8 cubic meters sand to 16 cubic meters ballast.

A ratio of 2 bags cement to 4 wheelbarrows sand to 8 wheelbarrows ballast is 1 to 4 to 8 which is still low for concrete works such as foundation footings and beams which require a ratio of 1 to 2 to 4 or 1 to 3 to 6.

This type of mix works well for single storey residential houses.

BUILDING COLLAPSE.

In the event that the ratio of 1 bag cement to 4 wheelbarrows sand to 8 wheelbarrows ballast is used for a building that is several storeys high, serious risk of collapse is imminent due to a very weak cement ratio. This could be the reason for the various building collapse being witnessed in Kenya and recently in Tanzania and India.

Francis Gichuhi Kamau, Architect.

info@a4architect.com

0721410684.

BUSINESS PLAN FOR GREEN HOUSING .
PROJECT DESCRIPTION
The Project consists of 76 maisonettes within a 7.5 acre piece of land

SUMMARY A4architect has conceptualized the whole project to embrace aspects of Green Architecture .
We have phased the project into 3 as shown below .

MAISONETTE SIZE AND PRICE.
PHASE 1.
Phase 1 has 20 units sitting on a 2.5 acre piece of land. These units are 230m2 in plinth area
PHASE 2.
Phase 2 has 24 units on a 2.5 acre piece of land. These units are 190m2
PHASE 3.
Phase 3 has 32 units on a 2.5 acre piece of land . The units are 170m2 .
The roads have been planned with a width of 9m so as to give the aura of large greenery within the estate.

COMPETITION.

Green environment friendly design will lower life-cycle operating costs. The result is a quality
product that is available at a reasonable price to a large market. Sustainability
Sustainability is the key value of the designs conceptualized by a4architect. Fences in between houses have also been designed to incorporate live growing fences to achieve the green effect.
A water body and river will be created within the Phase 3 area next to the road to enhance the aesthetics.
Intelligent design and landscape work that can optimize the efficiency of a home to use natural energy and cooling sources. Design solutions will be as below
o Intelligent design and site orientation
o high-performance doors and windows
o Low-VOC and non-toxic paints, finishes and adhesives
o Formaldehyde-free cabinets and adhesives
o Low-flow fixtures and appliances
o Energy-efficient appliances
o Sunroofs and light tubes
o Solar water heating
o Tankless water heating
o Natural ventilation
o Solar photovoltaic power
o Green roofs and walls

Use of the green architecture concepts will elevate the project above the competition.
Green Architecture consumers are a relatively new market category that is increasingly being
profiled, understood and sought after. The major motivations for customers to purchase a green home include environmental responsibility, lower energy use and electricity bills, and benefits to personal health. The architectural design is poised to take advantage of a paradigm shift in product markets.

CONSTRUCTION AND MARKETING.

Experienced Building Contractors and Real Estate Agents will be appointed through selective tendering process and provided with necessary technical support from the A4architect design team.

Francis Gichuhi kamau, Architect.
info@a4architect.com
0721410684.

STRUCTURAL INSULATED PANEL HOUSING IN KENYA. 2013.

The first types of Structural Insulated Panel housing in Kenya were steel sandwich types. These are 2 metal plates with polystyrene sandwich in between for insulation purposes. These panels then interlock to form the wall and roof structure.

These can be seen at the Chinese company constructing Thika super highway offices opposite Warren concrete at Kasarani. Also, the road construction company constructing Namanga road at Kajiado have used such.

Of late , another type of SIP, made using concrete has entered the Kenyan market. It’s called the Fibre Cement board.

Another is the Oriented Strand Board type. Oriented Strand board is a material similar to ply wood that forms the external skin with the inside sandwich made from insulating material such as polystyrene.

There is also reinforced concrete panel ype of construction. This produces heavy panels which require cranes to hoist. There are currently in use at Ruiru at the Dhodia group warehouses. These are very strong and long lasting.

Fibre Cement Board.

National Housing Corporation is in the process of constructing a factory to produce these types of SIPs. A Chinese company along Mombasa road has been active of late in advertising for the sale of these boards.
Construction Cost Savings.

SIP panels only deal with the wall and roof elements of construction. A typical building has several elements namely, foundation, walling, roof, windows/doors, finishes, services eg plumbing/electrical works and external works such as septic tank, fence, gate. To achieve substantial savings, all these elements must be designed to save at least some % from the total cost. To achieve cost reduction, someone needs to do much more apart from only saving from the wall and roof elements.

Current wall cost comparison.

The SIPs available in the market cost approx. kes 1800 per m2 without transport and labour. Masonry wall costs kes 800 without transport and labour.

Each stone is approx. kes 60 and there are 12 stones in 1 m2.
Therefore, if the site is in a place where masonry stones are available, there will be savings if the stones are used compared to the SIP panels. On the other hand, areas which don’t have masonry stone eg Nyanza, North Eastern, Eastern provinces, the SIP panels would be a considerable option.

Durability.
Natural quarry stone is the most durable, with a lifespan of 50 years. This can be seen in the numerous 50 to 100 year old bungalows constructed during the colonial period in Upper Hill, Kileleshwa and Kilimani areas OF Nairobi.
The SIP Panle durability depends on how thick the outer panel is. The thicker, the longer the durability.

Design.
The house dimensions needs to be designed in multiple lengths of 1.2m and heights of 2.4m. This is the standard length and with of the average panel. This ensures less cutting/wastage.

Francis Gichuhi Kamau, Architect.
info@a4architect.com
0721410684

JOINT VENTURES FOR CONSTRUCTION PROJECTS IN KENYA.

1. How does the JV work?

A Joint Venture works whereby a land owner does not have the requisite funding enabling him obtain financing from a bank. In most cases, banks require that the land owner fund approximately 30% of the total cost of the project including land and consultancy fees.

Where the cost of land is less than 30% of the total costs, banks require that the land owner top up the difference either using cash or construction input till foundation stage. This top up is what lacks to most land owners. Joint Venture partners come in to assist the land owner reach the required bank minimum of 30% contribution by the land owner.

2. What is the role of the Land owner in JV?

The land owners role in a JV is to avail clean land that has no encumbrances. The Land owner will need to employ consultants who will be able to negotiate with him for a good deal with the JV partner. In most cases, the Joint Venture partner takes a minimum of 51% of the total profits regardless of the contribution.

For example, say the value of the land is 15% of the total construction project cost. The Joint venture partner puts in the other 15% in form of cash so as to reach the minimum bank lending threshold of 30%. In a good Joint Venture negotiation, the Land owner should be able to get the majority percentage of profits even through the contribution between him and the Joint Venture partner is the same.

3. What would be the land owners contribution?

The land owners contribution is clean unencumbered land. We at www.a4architect.com can team up with the land owner to provide consultancy services, namely architectural, structural, quantity surveying, project management. This will push up the land owners contribution so as to enable a better Joint Venture negotiation deal.

4. What is the land owners benefit?

Once construction is through and the property sold, the land owner stands to gain form at least 51% of the profits from the proceeds . Profit is what remains after all costs of construction are added up together. The major costs to construction are
1.Land
2.Statutory fees to Local Authority and N.E.M.A
3.Building construction
4.External works construction eg roads, septic tank, bore hole, fence
5. Architectural, Quantity surveying, engineering, legal and project management fees.
6. Sales agents commissions and advertisement/marketing costs.
7. Bank loan interest repayments.

5. Who is the Joint Venture financier?

Joint Venture financiers are usually local banks. Once the land owner agrees with the Joint Venture partner in terms of the contribution, the Joint Venture partner together with the land owner register a company with each having commensurate percentage of ownership e.g. if they agree on 60 % vs. 40%, then the company ownership will suggest the same. The land owner then transfers the land title to the company.

This means that the land is now co owned the the original land owner together with the potential Joint Venture partner. With the co owned land, they both apply for a construction loan from a bank.
The bank charges the land title as collateral and releases the construction funds. Once construction is through, the original land owner and Joint Venture partner share the profits as per the company registration and the company is finally dissolved.

Francis Gichuhi Kamau, Architect.
www.a4architect.com
info@a4architect.com
0721410684

Francis Gichuhi Kamau, Architect.

LAND PRICES IN NGONG TOWN.

Land price in Ngong is dependent on the distance from Ngong town. Plots within Ngong town sell for 8 to 10m for a 1/8th acre which translates to 70m per acre or 35m per 0.5 acre. Plots 500m from tarmac go for between 4 to 5m per 1/8th which translates to 35m per acre or 18m per half acre.
Plots located 1km from tarmac costs around 2m per 1/8th which translates to 14m per acre and 7m per 0.5acre. Plots located 2km and above from tarmac cost between 1 to 2m per 1/8th which translates to 7 to 14m per acre or 3.5 to 7m per 0.5 acre.

Distance from main Ngong to Nairobi tarmac is the main determinant of price. Distance from Ngong town also affects price with plots closer to Nairobi fetching higher than plots farther away.

Ngong town is approximately 22km from Nairobi CBD.

Distance from large shopping developments such as the Juanco shopping centre also affects land prices.
An upcoming large supermarket development within the Ngong PCEA church land will also affect land prices.
Land in Ngong can be used to construct high-rise buildings.
There are no restrictions to the types of developments that can be constructed apart from the Kerarapon area which borders Karen and is zoned for single family residential use only.
Just like Karen whereby only one house is to be constructed in a minimum land size of 0.5acres, Kerarapon has similar land restrictions, the only difference being the minimum land size of 0.25 acres. Plots here sell for kes 5m per 0.25acres, translating to 20m per acre.

Land in Karen sells for 30 to 40m per acre for residential and 50 to 60m per acre for commercial land near or next to the main tarmac road.

Ngong area neighbors Kibiku, Matasia ,Kerarapon and Karen/Ololua forest.

BUILDING MATERIALS.

There are stone quarries in Ngong Oloolua area , Ongata Rongai Gataka area and Kiserian along Kiserian Isinya road. The Oloolua and Rongai stones are hard and mainly used for the foundation. The kiserian stones are soft and yellow in colour so they are mainly used for superstructure walling and decoration.

WATER.
nogng area has plenty of water from underground reservoirs. various individuals and organisations have sunk boreholes and already have existing water piping networks that serve the water to individual plots.

ELECTRICITY.

Blackouts are quite common during the day and there is power rationing on Thurdays during the day.

Francis Gichuhi Kamau, Architect.
info@a4architect.com

CONSTRUCTING BUILDINGS IN SWAMPY GROUNDS.

Demand for land has led mankind to think outside the box in order to accommodate and build on top of wetlands.
Land around Runda, Kiambu road and Kasarani, near Thika Super Highway is prone to dotted marshlands.

The land value per acre, approximately kes 40m per acre, is quite high.

This means that the extra cost of expensive foundations that can support buildings on top of wet lands will be able to be returned from the rental/sale income of the building. If the land value was low, it would be more prudent to look for alternative land that will not necessitate an increase in foundation costs.

PILE FOUNDATION.

Using Pile foundations is a good way of constructing on march lands. Holes are drilled into the wet ground till solid rock, water drained out and a casing fitted inside to prevent water from entering into the hole.

Steel rebar is then put in place and finally, concrete poured inside. The exterior casing is then removed.
A concrete column is now in place to support the building. Most of the high-rise 20 floors and above buildings worldwide are supported through this method.

COST.

This method requires specialized mechanization and engineering expertise hence there will be a slight increase in the foundation construction costs compared to other normal foundation methods such as the common strip foundation method.

The returns on investment will be eventually realized since the cost of pile foundations is very minimal compared to the cost of land and rental/sale value of the complete building.

Francis Gichuhi kamau, Architect.
info@a4architect.com
0721410684

RUNDA KIAMBU ROAD HOUSING ESTATE
GREEN ARCHITECTURE CONCEPT.

84 units have been conceptualized. To increase the greenery footprint, the following will be incorporated in the design.

1. Underground car park.

The plinth area below the ground floor will be designed into an underground car park. To save on light and ventilation costs, the underground car park will be raised 1 m above the ground level so as to allow for natural light and ventilation.

2. Roof garden.

The green plinth area occupied by the built up space will be replaced by a roof garden of the same plinth area size.

3. Wall planters.

The architectural design will strive to achieve approximately 40% of wall surface to be covered by green plant material designed into an aesthetically appealing pattern.

This will increase the green foliage cover and reduce the concrete jungle feel, thereby increasing project value.
A 200m2 ground floor useable space, including the car park will be achieved in the design.

SPACE SAVING.

The typical 1/8th plot has a surface area of approx. 430m2. A typical residence within such a plot will occupy the ground surface by approx. 130m2. This leaves out a total green space of 300m2.

In this project, we have designed the unit to incorporate 200m2 of useable ground level space plus a further 50m2 of roof top green garden , bringing the total green space to approx. 250m2. This is close to the available space achieved by the typical 1/8th acre plots. The actual space offered is 1/16th acre while the output green space offered is close to the effective space achieved on a 1/8th acre space.

By utilizing a slender, vertical space with 3 to 4 levels, including underground parking, we are able to offer the house occupants with green surface area nearly equivalent to space offered by 1/8th acre plots yet the overall space is actually 1/16th acre.

Francis Gichuhi Kamau, Architect.
info@a4architect.com
0721410684