Roofing guides

Gauge refers to the thickness of the steel before coating. The lower the number, the thicker the sheet. Gauge 28 is our heaviest common option and is what we recommend for commercial spans, exposed sites and coastal areas.

Gauge 30 is the sweet spot for most Kenyan homes: strong enough to walk on between purlins spaced at 750mm, yet still affordable. Gauge 32 works well for boundary walls, sheds, animal structures and short-span extensions.

Whatever gauge you choose, insist on genuine aluzinc base metal and ask for the coating mass. A cheap sheet with thin coating will rust long before a properly coated one.

Start with the plan area of your roof, then add the overhangs on all sides. Multiply by the pitch factor: roughly 1.05 for a shallow pitch, 1.15 for a standard 22-degree pitch and 1.25 for steep pitches.

Divide the covered width by the effective cover of your chosen profile (usually 950mm to 1000mm) to get the number of sheet runs. The length of each run is your rafter length plus 100mm of eaves overhang.

Add 5% for cuts and laps, then list your accessories: ridges, valleys, flashings, roofing nails and rubber washers. Send us the dimensions on WhatsApp and we will do the take-off for free.

Clear gutters and valleys of leaves and dust so water can move fast. Standing water is what pushes moisture under laps.

Walk the ridge and check every fastener. Any nail that has lifted should be re-driven with a fresh rubber washer, and any scratched paint should be touched up the same day.

Finally, look at the underside from inside the roof space during a downpour. Damp purlins and dark streaks show you exactly where water is entering.