1. Flat roof Preparation
With older houses we start by carefully removing the existing roof in a neat and orderly manner. We then further assess that the existing roof joists are secure and free from rot and inspect for insulation
2. The deck is laid
We use 18mm tongue and grooved OSB3 boards which are designed to minimise expansion and contraction. The boards are laid length ways at 90° to the roof joists. A 25mm expansion gap is left when boarding near a wall. The boards are staggered to make sure there are no week points in the flat roof. The boards are then fixed to the joists using a nail gun or screwed down with a screw gun.
3. Edge Trims
The Edge Trims are pre manufactured out of GRP, it has a matt finish on the one side for bonding purposes and a glossy finish on the other side. The trims are stuck to the boards using a polyurethane adhesive which is applied with a skeleton gun making sure that there is a consistent 30mm bead at 300mm centres. We then massage it into place so confirm that there is a good bond formed. A nail gun or stapler is then used to fix it into position.
4.Bandaging
For the next part of the process we mix the GRP Roofing resin with a catalyst which hardens the resin so it can cure. Chopped strand mat which is made from glass fibres or fibreglass is rolled out into position to cover the OSB3 roof deck and then cut with a Stanley knife with a minimum of 50mm overhang on the edge trims, we then continue this process until we have cut in enough to cover the whole roof. We now neatly roll up the strips and pack away until needed. Joints in the trims are bandaged as well as the corners where 200mm squares of mat are cut for extra strength. We apply the well mixed catalysed resin to both sides of the bandages to ensure the bonding process.
5. Laminating
We apply the first coat of resin to the OSB3 boards with a roller before the bandaged edge trims and corners have cured. The pre-cut lengths of strand mat are now placed into position and rolled out with the resin dipped roller as we unroll the mat meter at a time. We repeat this process until the whole roof is completely covered. We now allow the resin to soak into the mat to break down the emulsion binder for a few minutes.
We now use a paddle roller down the mat, making sure we get right into the edges. We know when the laminate is correctly wetted out when it becomes completely transparent with no white or opaque areas.
6. Topcoat Preparation
After the Resin has cured we sand the roof with a light grit sand paper so we can end up with a perfect finish. A silicone gun is used to seal any edges with abutting walls. A C100 simulated Lead flashing is siliconed into place if needed before we apply the top coating.
7. Top coating
When the laminate is semi cured (not sticky) we apply our finishing resin which is mixed with a catalyst for it to cure. We have various colour options for your flat roof; we simply mix your chosen colour dye with the resin.
The topcoat will cure very fast, and will leave you with a completely waterproof roof, with no joints or seems.
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