First, the tiled roof was stripped back and the timber frame of the new extension was installed with a rainwater gully formed at the intersection of the new extension and the existing tiled roof, the gully having a 2 inch fall from left to right built into it.
The roof and gully was then lined with interlocking OSB3 boards and a lead outlet fitted at the right hand end of the gully to allow rain water to exit the roof and into the pre-installed drainage system.
The install of this grp was quite easy as there were no preformed trims to be fitted to the outer perimeter as with a standard install, the design being such that a powder coated Aluminium box section was to be fitted, with a rebate over the edge of the grp roof with its own in-built seal applied.
The first layer of our grp system was then installed, this comprised activated liquid resin, applied to the boarding, we then roll out our pre-cut fibre glass matting over the area resined, before applying a further coating of activated resin to the top of the matting. A metal pad roller is then used to push the 2 layers of resin together through the matting. It's really important when doing this system that firstly, you use enough liquid (we usually allow approx' 1.3ltrs per sqmtr of roof) and secondly, a pad roller is used to get the liquids bonded through the fibre glass matting. failure to do so can result in white dry looking patches on your matting and weak spot in the water tightness of the system.
Once the first layer was complete and hard cured we then installed our 1st layer of activated topcoat, a nice thick layer should be applied to the entire roof surface. Once you apply this 1st topcoat, you can then see any small anomalies that were invisible to you before, ie: fibre glass strands sticking up,resin drips from your roller. These can then be sanded down to get a nice smooth surface on the roof, before a 2nd layer of activated topcoat can be applied. (Topcoats for the grp system come in every colouron the spectrum but the standard buy off the shelf colour (unless specified) is a gun metal dark grey).