Roof Waterproofing

A leaking roof is rarely a single hole — it is almost always a chain of small failures that only become visible once water has already travelled through your ceiling. By the time you see a stain or a drip, the water has moved along rafters, around insulation, and across the underside of the deck, so the visible mark is often metres away from the actual entry point. That is why we never patch the stain. We trace the water back to its source.

Our roof waterproofing work begins with a full inspection of the roof surface, the parapets, the penetrations, and the drainage. We look for cracked or blistered membrane, failed laps at sheet joints, open detailing around pipes and vents, and ponding areas where water sits long enough to find a way through. We also check the condition of the substrate beneath the membrane, because a membrane is only as good as the surface it is bonded to.

For most roofs in Rwanda we specify torch-applied modified bitumen membranes, which are tough, repairable, and proven in tropical climates. Where the roof has complex geometry, multiple penetrations, or a substrate that cannot take a torch, we use liquid-applied polyurethane or acrylic coatings that form a seamless, fully bonded layer. Both systems are detailed at the parapet upstands, the corners, and every pipe penetration, because that is where the vast majority of roof leaks actually begin.

We also correct the drainage falls where necessary. A roof that ponds water after every rain is a roof that is being slowly destroyed — standing water adds weight, accelerates membrane ageing, and forces water through any weakness under hydrostatic pressure. By re-establishing positive drainage to the outlets, we remove the standing water that would otherwise undo the new membrane within a season or two.

The result is a roof system that is engineered for the structure, installed by trained applicators, and documented with photographs at every stage. You receive a clear scope of work before we start, a written specification of the system we will install, and a warranty that covers the workmanship. If the roof leaks again, we come back — that is the standard we hold ourselves to.