GRP Flat Roof Alternative

A well-specified GRP roof laid over a correctly built deck can give twenty years or more. In practice we see many crack much earlier, usually because the deck was too thin or insufficiently supported, or because the laminate was applied to damp boards or in unsuitable weather. Crazing around trims and over board joints is the earliest warning sign.

Yes. Once the surface has been abraded, cleaned, made good and primed for a polyester substrate, the liquid system bonds well to GRP. This is normally far cheaper and less disruptive than cutting out the laminate and the deck below it.

Nearly always because of movement in the deck. Boards that are too thin, joists at too wide a spacing, inadequate noggins at board edges, or laminating over boards that had not fully dried will all produce early cracking, typically over the board joints and at the internal corners of upstands.

A liquid system generally handles trafficked balconies and terraces better, because the detailing around thresholds, drainage channels and balustrade posts is formed in one continuous membrane rather than laminated in sections. Anti-slip surfacing can be built into the finish where the area is walked on regularly.

GRP installation releases a strong styrene odour that carries a long way and often draws complaints on terraced streets. The Ultraflex resins are low odour by comparison and cure far faster, so any smell is short lived, and there is no hot work or flame involved at any stage.

We can, and sometimes that is the sensible short-term answer. But a crack is a symptom of movement, and a rigid patch simply relocates the stress to its own edge, so localised GRP repairs commonly fail again within a season or two. Overlaying the whole roof with a flexible membrane deals with the cause rather than the symptom.