Author: A4KENYA

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A 1m2 of masonary walling, assuming a 200mm/9inch stone thickness, will be as below.

Horizontal mortar.

Surface area =0.2m x 1m=0.2m2.
5 Surface levesl in 1m2 =5 x 0.2m2=1m2 For horizontal mortar joining the stones.

Vertical mortar.
Surface area=0.2 x 0.2=0.04m2.
15 vertical surfaces in 1 m2 of wall=15x 0.04=0.6m2.

Total surface area =0.6 + 1=1.6m2.

Volume = assuming a 1 inch/0.03m thickness =0.03 x 1.6=0.048 m3 of cement sand mortar per 1 m2.

Ratio of cement to Sand for walling mortar.
Assuming a cement/sand ratio of 1 to 8, the volumes will be as below.

4 sand 1 cement.
The usual mix by fundis in Kenya for cement sand mortar for joining and plaster is 4 wheel barrows of sand to 1 bag of cement.
2 bags of cement are equal to 1 wheelbarrow.
This translates to 2 bags cement to 8 wheel barrows of sand or a ratio of 1 to 8.

Sand volume will be 8/9 x 0.048m3=0.042m3

Cement volume will be 1/9 x 0.048m3=0.0053m3.

Cost.

Weight.

SAND.
Sand density is 1.6 tonnes per m3.
Therefore, 0.042m3 of sand will weigh 0.07 tonnes=70kg.

1 tonne of sand costs kes 2,000.

0.07 tonnes of sand will cost kes 137 .

CEMENT.
Cement density is 1.6 tonnes per m3.
Therefore, 0.0053m3 of sand will weigh 0.009 tonnes=9kg.

1 tonne of cement costs kes 14,000, Equivalent to 20 bags cement @kes 700 per bag.

9kg of cement will cost 9/50 x kes 700=kes 126 for 1 m2 of walling.

Total cost of cement/sand mortar will be 126 + 137=kes 263 per m2.

Labour.

A fundi plus one mtu wa mkono will complete 150 stones per day.

1 stone is 0.2 x 0.4=0.08m2. 150 Stones are 12m2 of stone wall surface per day.

Labour cost is kes 800 for a fundi plus kes 400 for a mtu wa mkono =kes 1200 per day.

Cost of labour for 1 m2=kes 1200/12m2=kes 100.

Total cost of cement, sand plus labour =kes 363 per m2.

In 1 m2 of masonry stone walling,

costs are as below
stone 13 pieces@kes 50=kes 650
Sand=kes 137
Cement=kes 126
Labour=kes100
Total =kes 1013

Sand has increasingly become more expensive than cement.This is because of environmental concerns on river sand harvesting hence heavy taxes levied on sand harvesters. Labour is also threatening to surpass the estimates given due to the increased higher costs of living around Nairobi.
Cement prices have even gone lower, with Simba cement reducing their prices to around kes 600 per bag recently.
Stone prices will also increase due to rules limiting the tonnage of lorries travelling along Thika super highway. Juja is the largest supplier of machine cut stones in Nairobi hence affected by Thika road tonnage limit where the lorries are now carrying less tonnage for the same transport cost.

Francis Gichuhi Kamau, Architect.

info@a4architect.com

Mabati gauge 30. costs 570kes for a 2m by 0.8m wide sheet.
Mabati Gauge 32 costs 470 for same.
This translates to kes 350 per m2.

Add cost of timber frame support, say 4m x kes 30 per foot.
Cyprus 2 x2 costs around kes 24 to kes 30 per foot. This translates to kes 100 per linear meter.

Assuming 1 square meter of mabati requires 4 linear meters of timber for support, this translates to kes 100 x 4 = kes 400.
Add labour/nails say kes 200
=kes 950 per m2

Lets calculate cost of stone wall per m2.
A machine cut stone, 6 x 9, costs kes 50 delivered to site.
There are 12 to 13 stones per m2=kes 650 per m2.
Add kes 200 labour/cement=kes 850 per m2.

From this, we can deduce a mabati walling is kes 100 more expensive than a stone walling around Nairobi.

Stone, apart from the advantage of cost, has several other advantages as outlined below.
1. its a better insulator. This means the house stays warm at night and cool during the day , unlike mabati which is too hot during the day and too cold at night.
This reduces comfrt levels of mabati houses hence lower rental income if ther are for rent.
2. Security.
Mabati houses are insecure in case of a burglar attack. This means owners of mabati houses will feel insecure and will also be at risk of loosing valuable goods due to the ease of breaking into a mabati house. This in turn leads to low rental income if its for rent.

3. Class.
Stone houses elevate the social class of the occupants .

Upcoming informal settlements.
New informanl settlements in Nairobi have already done their mathematics and are now using stone walling for their houses since this is the cheapest method of constructing a house.
A look at Njiru, Chokaa areas will show this use of stone for informal settlements.

In other developed countries such as Australia, only a very few high income group can afford to live in stone houses.

Francis Gichuhi kamau, Architect.
info@a4architect.com

Kenya land was first appropriated by the British colonists in the 1890s. All land in Kenya was then taken to be the property of the British colonists.

In the 1920s, Britain then marked out the most productive land in Kenya, which is around 20% of Kenya’s land mass and sold it to British citizens in 1,000 acre chunks. These areas were referred to as the White highlands, namely central province, Rift Valley province and parts of Kitale.
Kenya land size is 144 million acres.
20% OF this land is arable, i.e 29 million acres.

At attainement of independence in 1963/1964, land onwership change from the British to indigenous Kenyans was crafted.
A solution known as the 1 million acre settlement scheme was hatched by the British and Kenya Governments whereby Kenyans were to buy back the land from the white settlers.

This was funded by world bank.

http://www.macalester.edu/geography/AGR/journals/1964_2_4.pdf

The Swynnerton Plan, hatched in the 1950s, aimed at creating a middle and upper class indigenous Kenyans in central province. This was to be achieved by enabling a few central province Kenyans to own large tracts of farm land previously owned by the colonists then they employ the large masses of people.

http://en.wikipedia.org/wiki/Swynnerton_Plan

The British implemented the Swinnerton plan from the mid 1950s by rewarding loyalist Kenyans with large swathes of land and encouraging them to get into cash crop farming.
The over emphasis on cash crop farming would in later years lead to lack of food since food crops were not being planted.

The British land alienation policies which were not well designed to offer indigenous Kenyans access to land led to massive relocation of Kikuyu landless people into the Rift Valley former white highlands.

Current land situation in Kenya.

British interests and Government still continue to hold large chunks of viable land around Nairobi and within the white highlands.
Delamere owns 100, 000 acres from Naivasha till Nakuru. Large British tea holdings still own large acres of land.
A few indigenous Kenyans who were favoured by the British colonists and rewarded with huge chunks of land around Nairobi still own. Some of them have resold the land to other people.

Way forward.
The National Land Commission should come up with land use policies that ensure these large land owners are forced to utilise the land .This can be done through implementing taxes on idle land. This will force these owners to either ensure the land is used productively, hence offering employment or the land is sold to those with the entrepreneural skill to utilise it.
It is really not a big deal as to who owns the land so long as the Government can ensure they are Kenyan citizens and are using the land to create employment.
Agricultural areas around Nairobi such as Kiambu should be taxed higher so that the tax revenue raised can be used to support green house agriculture and irrigation in the arid areas.
Francis Gichuhi Kamau, Architect.

Plastics are gaining entry itto main construction industry.
We have the new uPVC ceilings, wood plastic wall and column coverings,uPVC floor coverings and PVC material used for roof.
Its just a matter of time before an enterprising industrialist comes up with interlocking plasctic boxes that can be filled with soil and be stacked and joint together to form structural walls.
This will solve alot of problems.
This will make construction of walls and roofs much cheaper.
This would also enable soil that cant be used to create stabilised soil blocks, eg black cotton soil or sandy/salty shoreline sand, be useful in construction as an insulating infill inside the plastic interlocking containers.
This would also provide a method of recycling plastic.
It can be moulded into various patterns, colours and textures.

The plastic bricks interlock just like in a LEGO toy to create walls.
http://www.youtube.com/watch?v=Rmg-g9u8y7o
Interested venture capitalists/plastics manufacturers can get in touch so that we develop this into a commercially viable alternative construction method in Kenya.

The usual Roto tanks supporting thousands of liters of water show that plastics are strong enough to be used for walling since walls dont support heavy loadings except roof loading.

Plastic wallings can also be used to create vertical wall gardens, complete with internal watering systems.

http://www.alibaba.com/product-gs/252949808/Modular_green_wall_planter_Modular_green.html

Plastics for Roofing.

PVC sheets are a common roof feature for bars,restaurants,churches and out door tents all over Kenya.

Use of PVC for roofing can be creatively introduced into residential housing. This can be used as an outdoor living area extension.
Use of different pvc roofing sheet colour generates a desirable ambience to the space within it.

For example, the outdoor sitting area for the Ehiopian restsurant at Utalli House in Nairobi CBD has a red colour which makes the interiors very exiting.

Rafikiz restaurant along Langata road also has utilised an interesting pvc roof design.

Tulips restaurant, Kileleshwa, designed by a4architect.com, is also a good example of pvc roofing being used to extend living areas of permanent buildings.

Francis Gichuhi Kamau, Architect.
info@a4architect.com

Research into making building construction more efficient using 3 d printing is on going . Soon we would be able to print our buildings directly from our computers.
This technology is the latest in the field of construction.
Dr. Behrokh Khoshnevis of the University of Carlifornia is leading this research through a method called contour crafting.

In this method, a giant 3 d printer with a moveable flexible arm pours and moulds concrete from a pre mix concrete lorry along the contours of the building wall, slab , roof and other elements.

The moveable arm interweaves the concrete to form a firm wall structure.
Currently, concrete is the most widely used construction material.Ways and methods of making the concrete cheaper, such as creating fibre cement, can be utilised to reduce costs for bungalow type buildings that don’t require heavy structural walls.

The robotic arm of the 3d printer can be controlled to print exactly as drawn on the computer.

Currently, concrete prefab panel construction is made costly due to need for cranes to lift the heavy panels to the higher levels. With 3d printed buildings, there is no need for this since the pre mix lorry concrete pump will pump to the higher levels.

Watch this video here on how the technology works.

For Kenyan situation, much customisation will have to be done for this to be practical. Pre mix concrete lorries are already available here. The robotic printing arm design and programming will need to be undertaken by say, Numerical Machine Complex or any other private sector industry with a knack for innovative technology.

A person can aid the printer to ensure it works perfectly till the mechanisms are fine tuned to perfection.
Francis Gichuhi Kamau, Architect.
info@a4architect.com

Housing costs in Kenya.  Why cost of acquiring a home in Kenya is high.

On average, Kenya has one of the lowest construction rates in the world. Kenya also has one of the highest land prices in the world, much higher than in developed countries such as USA.

Housing cost can be divided into 3 basic categories.

1.Low cost

2.Middle cost

3.High cost

Low cost housing.

This costs an average of kes 20,000 per m2 to construct. These houses are mostly in areas such as Kayole, and over 2 km from tarmac in major towns around Nairobi.

The breakdown is as below.

From this, we can see land cost is around 16.5 % of total housing costs. This is more or less within the international averages of 20%.

This means that in low cost housing, bank interest at 11.9% of total housing costs is what needs to be adjusted so as to reduce costs.

Middle cost housing.

In middle cost housing, using the average cost of construction at kes 25,000 per m2 for a 100m2 house, the land cost is 32% of the total housing cost. This is higher than the international average of 20%.

Such areas as Kitengela, Ngong, Ruiru where a 1/8^th piece of land costs 1.5m will give the scenario above.

The financial charges, with interest rate at 18% is also quite high.

Solution will be for Government to look for ways that will reduce interest rates and reduce cost of land.

High cost.

For high cost housing, an abnormally huge percentage of housing costs are taken up by land. The 40% land costs are way beyond the average 20% in other parts of the world.

In high class neighborhood such as Kahawa sukari, garden estate etc, most of the housing cost is taken up by the land.

Conclusion.

Land price appreciation in Kenya on average has a rate of between 25 to 100% annually.

Last year the price of 1 acre of land in Upper Hill CBD was kes 250m.

Current asking prices for the same acre is kes 400m. This represents a 60% appreciation rate per year.

Last year a residential plot in Syokimau 1km form tarmac was going for kes 1.5m. Its currently selling for 2.5m. This represents 66% appreciation annually.

This appreciation on land price is higher than the international average of 5 to 10%.

Construction cost for a middle class building in 2008 was kes 18,000 per m2. After 5 years, it has gone to kes 25,000.

This represents 8% annual appreciation rate which is normal and in tandem with the international rates.

Clearly, Kenyan land appreciation rates have gone viral and only the Land Commission can tame this with the introduction of Idle land taxation.

Francis Gichuhi Kamau, Architect.

info@a4architect.com