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Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 2:43 pm
by JackyJoll
The old corrugated roof of the shed is acting like heavy rain and melting snow soaks through it. Does corrugated asbestos go like that?
Have any of you had any success sealing it with a paint or coating?
I am absolutely not asking for health and safety or environment-saving advice.
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 2:48 pm
by Wreckless Rat
JackyJoll wrote: Tue Feb 16, 2021 2:43 pm
The old corrugated roof of the shed is acting like heavy rain and melting snow soaks through it. Does corrugated asbestos go like that?
Have any of you had any success sealing it with a paint or coating?
I am absolutely
not asking for health and safety or environment-saving advice.
Yes it can, sealing it can be done with a suitable roofing sealer, but it wont last long. ime
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 3:48 pm
by Kneerly Down
I would use this:
https://www.screwfix.com/p/no-nonsense- ... 5ltr/57474
'Normal' paint/bitumen products rarely work well IME.
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 4:35 pm
by JackyJoll
Thanks. That does look hopeful.
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 4:50 pm
by OBO
They were always porous from new.
Pressure washing makes them worse. (And brittle).
OBO, old industrial roofer. ☺
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 4:52 pm
by OBO
Bitumen products work fine IF you use an appropriate primer first.
Re: Does asbestos roofing go porous?
Posted: Tue Feb 16, 2021 5:05 pm
by Ditchfinder
We just installed a new plastic roof on top of the asbestos roof on our shed. Cheap, easy and has been weatherproof ever since.
Re: Does asbestos roofing go porous?
Posted: Wed Feb 17, 2021 12:18 am
by The Martian
Fenacryl, it's a bostik product that you can get in Screwfix for about £40 per 5l. Two will do an average size garage roof.
Just paint it on (do wear gloves it's a liquid polymer and it's a proper cunt to get off your skin).
Get the grey / silver rather than black as it reflects heat and lasts longer. I did an asbestos garage roof in it almost 4 years ago and it's still sound, also used it on flat roofs with good results.
Re: Does asbestos roofing go porous?
Posted: Wed Feb 17, 2021 8:06 am
by slowsider
Mine needs scraping again first - looks like sedum at the moment. The moss holds the water long enough to leak through.

Re: Does asbestos roofing go porous?
Posted: Wed Feb 17, 2021 10:25 am
by JackyJoll
Ditchfinder wrote: Tue Feb 16, 2021 5:05 pm
We just installed a new plastic roof on top of the asbestos roof on our shed. Cheap, easy and has been weatherproof ever since.
But that’s fixing it properly!
Re: Does asbestos roofing go porous?
Posted: Wed Feb 17, 2021 11:01 am
by Ditchfinder
JackyJoll wrote: Wed Feb 17, 2021 10:25 am
Ditchfinder wrote: Tue Feb 16, 2021 5:05 pm
We just installed a new plastic roof on top of the asbestos roof on our shed. Cheap, easy and has been weatherproof ever since.
But that’s fixing it properly!
I got a man in to do it (actually 2 of them) hence why it got fixed properly - everything I 'fix' is likely to need further fixes on an ongoing and frequent basis
Wasn't very expensive either - materials + 1 day labour for 2 of them.