You will hear many complaints from developers that their floor tiles are cracking and they start blaming ‘mutu wa tiles’. The tiler most likely has no blame. Such occurrences happen when a developer chooses to omit or use lower quality/specification of what in Kenya we refer to as BRC or, if your are from Central Bi-ara-si.
BRC Stands for British Reinforcement Company Ltd, a company that was the first to manufacture wire mesh fabric to be used in the construction industry. So, if you tell your fundi ‘aweke BRC’, you and the person who says ‘ile omo mpya inaitwa Toss’ or ‘ile Colgate ya red inaitwa Close Up’ are in the same wozzap.
‘BRC’ is a welded steel mesh made of longitudinal (line wire) and transverse (cross wire) bars welded together for use in reinforcement of foundations during construction. Mesh size refers to the size of hole measured as the center-to-center distance of line and cross wires in millimeters. It is made in accordance to KEBS standard 574:2008.
In a ground floor slab, the force action from above is opposed by an equal force from below (the bearing strata hence causing a phenomenon called heaving. Ground heave is the upward movement of the ground usually associated with the expansion of soils (mainly clays) which swell when wet. Heaving causes the slab to crack. To protect the cracking, the BRC mesh is included to resist the cracking effect.
The second function is mainly to take care of the phenomenon of sagging, which is basically the tendency of the mid-section of a structural member to bend downwards. To understand this phenomenon, take two chairs and suspend yourself with your head on one side and your feet on the other, facing downwards then send us a picture. Now you know how a slab feels.
When your structural engineer instructs that you use a certain gauge of BRC, don’t tell them ‘hiyo ni nono sana, zamani tulikuwa tunatumia kidogo’. Your engineer knows what they are saying. The quality of steel is not as good as it was 20 years ago.