Outer walls in a building have many purposes. With a wall you can control many things, like inside climate (direct unwanted sunlight, temperature, humidity, speed of the air, hold materials in suspension like slabs, beams etc.), you can restrict the movement of unwanted animals like keep out fisis/hyenas from attacking your daughters, also used as a protection barrier from unwanted persons like thugs and hooligans shouting ‘wamlambez’ etc. However, being the first point of visual contact, one may manipulate the walling to create character or express a unique design language.

One way to be unique is to explore a zero-joint system. This is a masonry type that the outward appearance looks like the stones are piled on top of each other without a mortar joint. (Mortar is a cement and sand mix). The trick is that the stones are chamfered so that the mortar joint is inside the wall. This gives it a classy finish devoid of hideous ‘key’ that is a construction fashion of the 80s and 90s. The zero joint can be used for a smooth finish or one with relief like a bush hammered finish.

For consistency of the finish, we recommend your Structural engineer indents all external columns and beams by about 50 millimeters/ 5 centimeters so that they can be cladded with slates of the same stone used for the zero joint.

This walling strategy is very labor intensive and will without a doubt cost a developer more. however, we have observed, in Buildings (specifically residential), walling as a component of construction cost, ranges from 7%-12% of the total construction cost. Basically, additional costs on walling are a very small fraction and may not adequately make drastic cost implications on overall cost. If you feel you really want to proceed with a zero joint, reduce your development in floor area by a mere 1-2% and you will be good to go. External walling is also considerably less in area than internal walls.

These are the average costs of walling (excluding plaster) we have observed in the last 12months. The figure consists of costs of materials and labor.

-Ndarugo high quality 1800-2200 per sq meter

-Zero joint Isinya/Gilgil/Naivasha Yellow 2700-4300

-Zero joint ‘orijino’ Nairobi blue 3500-5300

-ISSB 1300-1600

-EPS 2400-2950

-Concrete panels 2400-2950

-Bricks 2900-5800

-strawbale 1200-2600

Architects and Quantity surveyors list


Board of Registration of Architects and Quantity Surveyors of Kenya (BORAQS)

Transcom House Annex, Ngong Road.

P.O Box 40866-00100,

Nairobi – Kenya

Phone: (+254) 020 2728 444, 0726 243 005, 0780 496 588

Email: [email protected]

Engineers list


Transcom House Annex, 1st Floor, Ngong Rd,

P.O. Box 30324-00100 Nairobi, Kenya

TEL: +254-20-2719974

CELL: +254-735-330744, +254-722-509972

Email: [email protected]

Website: www.ebk.go.ke