This flat roof extension had been on for about 25 years so the built up felt system had lasted well.
Since undertaking full training in the GRP glass re-inforced plastic roofing materials I suggested the 20 year GRP Scott Bader system for this roof. The felt and boards were completely removed, an upgrade in insulation to the latest standards and then a new timber substrate and the grp system applied on top.
There were some timber repairs and remedial work to be done and the removal of the old gas vent which came through the roof. With the current spate of wet weather the newly installed roof covering has more than shown it is the material for the future and does it’s job very well indeed.
This is an extension being built up through a garage. Steel beams were put in to take the extension and a new formed flat roof was built to cover the steels. I used a GRP product, polyester resin re-inforced with chopped strand fibre glass and woven glass cloth tape. This has to be adhered to OSB3 Sterling board, GRP trims are used for abutments and edgings which are being fixed into place in this picture. Click images to enlarge for more detail
This image shows the rest of the wall trims being cut and fixed down.
All trims are fixed in place and ready for next stage which is sealing all joins and edges.
Resin is being mixed for use, the polyester resin is activated using a hardener to start the curing. The system has been used in marine applications for many years and is very similar to boat hull constructions, so you could say it has been well-tested against water penetration.
Jointing tape is cut to length ready to accept the liquid polyester resin
Applying resin to penetrate the jointing tape, once the resin hardens you have a very strong reinforced plastic that is also flexible and waterproof.
All joins and edges sealed and curing ready for the next part of the application.
Waiting for the applied chopped glass strand re-inforced resin to cure before the next process.
Perimeters painted first in the top coat.
Finishing the last of the GRP top coating.
All top coating finished. A GRP wall trim flashing is to be fixed into the brick mortar joint above the wall trim fillet.
This GRP roof drops down to the existing garage flat roof which is made of built up felt. We had to apply a torch on felt system below to finish and seal around the extension coming through the roof.