GRP TopCoat Flaking Re-coating ??

rideforever · 3 Jun 2021

Hi, got a GRP flatroof with a few flaky patches of the topcoat. Is it easy to re-coat in a TopCoat,diy?
What prep do I need to do? Clean off the birdshit and rub down the flaky bits?
Anything else?

Also regarding the weather, it's pretty hot at the moment ... when's the best time to do it ?

Or is it best left till Autumn when it's cooler?

Thanks for any help.

oldbutnotdead · 4 Jun 2021

Its fairly easy, long as you pick a dry day the temperature isn't that critical.
The topcoat is a grp resin as well, for it to get a good bond to the laminate you really need to sand or anglegrind the old topcoat off, but you can get away with a good hard sanding of the surface (so you are working on topcoat that hasn't had air/water exposure fot ages).
Once you've done your sanding, sweep the dust off, then sweep the dust off again, then mop the roof with acetone. While the acetone is drying, mix your topcoat, once the roof is dry get it on (roller is best). The acetone keys the old topcoat or laminate so you get a good bond to the new. Dont do topcoat too thick, it'll crack. Don't mix more than you can put down in half an hour. Enjoy

rideforever · 4 Jun 2021

oldbutnotdead said:
Its fairly easy, long as you pick a dry day the temperature isn't that critical.
The topcoat is a grp resin as well, for it to get a good bond to the laminate you really need to sand or anglegrind the old topcoat off, but you can get away with a good hard sanding of the surface (so you are working on topcoat that hasn't had air/water exposure fot ages).
Once you've done your sanding, sweep the dust off, then sweep the dust off again, then mop the roof with acetone. While the acetone is drying, mix your topcoat, once the roof is dry get it on (roller is best). The acetone keys the old topcoat or laminate so you get a good bond to the new. Dont do topcoat too thick, it'll crack. Don't mix more than you can put down in half an hour. Enjoy

Thanks. Is sanding really necessary, I'm a bit worried about inhaling the glass dust. Can I get away with giving it a wash and then mopping with acetone. It's only about 9 months old. ??

oldbutnotdead · 5 Jun 2021

If you don't sand it, the new topcoat may just end up being a coat of paint, prone to bubbling and flaking.
Paintsprayers masks aren't expensive, given that you're outside a throwaway covid mask will reduce your dust exposure.
If you have a few nice hot days, consider coarse wet and dry sandpaper- so sand it wet, let the water dry completely (24 hrs, exposed laminate is slightly porous) then acetone wash etc etc.

diynot

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GRP TopCoat Flaking Re-coating ??

rideforever

oldbutnotdead

rideforever

oldbutnotdead

DIYnot Local

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