Reducing cost of construction using roof pitch. Kenya.

Earthbag construction project at Kiserian on a leased property.

30 degree roof pitch.

30 degrees pitch

The round curvilinear room has a pitch of 30 degrees for roof. The roof surface area is 60m2. Asuming gauge 32 mabati roof at kes 300 per m2, the iron sheet cost is kes 18,000.

The truss length is 40m.Assuming 3 x2 cypress timber at kes 120 per meter, the cost is kes 4,800.
Total roof cost is kes 22,800.

The plinth area of the room is 32m2.
The cost per m2 for roof will be kes 760.

Roof pitch 5 degrees.
4 Degrees

With a 5 degrees pitch, cost will be as below.

Roof surface. Assuming Mabati gauge 32 at kes 300 per m2, the area is 54m2.
Cost of roof surface will be kes 16,200.

Timber structure.

The length of the timber trusses will be 35 meters.
Cost of timber , assuming 3 x2 cypress timber section at a cost of kes 120 per meter, will be kes 4,200.

Total flat roof pitch cost will be kes 20,400.

Cost per m2 will be kes 640.


Flat roof is cheaper by kes 2,400.
This is 11.7 % cheaper.

The cost reduction quite small.

Arch. Francis Gichuhi Kamau. (337 Posts)

Architect Francis Gichuhi . B.Arch. University of Nairobi. Registered Architect, Kenya. Member, Architectural Association of Kenya. Contacts. email Telephone +254721410684


  1 comment for “Reducing cost of construction using roof pitch. Kenya.

  1. December 2, 2015 at 3:55 pm

    Hallo Architect Kamau, Kindly l woud like to ask you for asistance about ahouse am about make the Roof ,20mtr* 10mtr how many mabati and timber do l Need .Thanks ,Emmy.

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