October 20, 20232 yr Hi. My neighbour had a flat foof put on his extension in early September 2023. He loves it but doesn't know much about glass fibre. The builders put 1 layer of glass fibre matting on it 4 weeks ago but haven't topcoated it. It's too late to get a proper bond after 4 weeks surely? Why would anyone wait so long to topcoat? Just wondering. Edited October 20, 20232 yr by DaveAF
October 20, 20232 yr Just needs a good rub down with fine sandpaper and it'll be fine. Topcoat in theory protects against UV damage, otherwise aesthetic. Looks like a pretty good job btw.
October 20, 20232 yr 9 hours ago, DaveAF said: 1 layer of glass fibre matting on FFS Just as well they have not put the top coat on. 1 layer is bugger all and will quite possibly cause problems in the not too distant future. If they use the right kind of resins, adding extra layers and a top coats onto fully cured substrate is not a problem. I will say that it does look a reasonable layup for 1 layer, nice and resin rich, which is a good thing.
October 21, 20232 yr 11 hours ago, SteamyTea said: FFS Just as well they have not put the top coat on. 1 layer is bugger all and will quite possibly cause problems in the not too distant future. If they use the right kind of resins, adding extra layers and a top coats onto fully cured substrate is not a problem. I will say that it does look a reasonable layup for 1 layer, nice and resin rich, which is a good thing. ?? Any kit I've ever used has been a specific one layer chopped strand kit. I didn't know multi layer was a thing.
October 21, 20232 yr Author 12 hours ago, SteamyTea said: FFS Just as well they have not put the top coat on. 1 layer is bugger all and will quite possibly cause problems in the not too distant future. If they use the right kind of resins, adding extra layers and a top coats onto fully cured substrate is not a problem. I will say that it does look a reasonable layup for 1 layer, nice and resin rich, which is a good thing. Oddly enough after they repaired a minor leak yesterday morning they finally topcoated the roof. No extra layers of matting though, just a paint over with the topcoat.
October 21, 20232 yr 1 hour ago, Conor said: I didn't know multi layer was a thing. 2 layers of 450g/m2 CSM would be normal, I would always recommend 3 layers. As a general rule, 1 layer of 450g/m2 matt is 1 mm thick and will take 900g of polyester resin. If going onto a very absorbent substrate like OSB, then the first layer will take more resin. Topcoat is around 350g/m2. This can vary quite a lot depending on the final usage i.e. aviation and walkways are treated very differently.
October 21, 20232 yr 18 minutes ago, Conor said: Glad I've only done a shed roof and a balcony then 🤣 Treat it as aviation, they usually fly off eventually.
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