what's this painted all over my slates?

[cjard]

On my slate roof is painted a grey substance. I can peel it off in sheets on some slates, and it bends and tears easily. Where the patination oil has washed off the lead it appears to have eaten into it and caused it to lift and go crispy somewhat like fallen leaves but bizarrely on the sunward side of the roof it looks in good condition with little lifting and on the dark side it peels everywhere. I can photo it if required. Its applied to slates on a former council owned utilities building dated 1926 but when it was applied is unknown

 

[Nige F]

Acrypol - or Turnerising

 

[cjard]

Thanks for the pointer Nige.. I looked them up and the resources I could find implied that both Acrypol and materials used in the turnerising process had a fibrous aspect to them. Having torn this stuff into little shreds in many different directions I didn't find any fibres in it..

Looking closely, it looks like sponge - kinda like a 1mm thick version of the other half's yoga mat, or a chocolate aero (only with smaller bubbles)
Soaking it in petrol made it expand and become a lot more rubbery, and burning it made rather acrid smell, like tar or plastic

Have you any suggestions for removing it, whatever it is? Should I try jetwashing it off, soaking it in something, burning it to a crisp?

 

[ed110220]

Thanks for the pointer Nige.. I looked them up and the resources I could find implied that both Acrypol and materials used in the turnerising process had a fibrous aspect to them. Having torn this stuff into little shreds in many different directions I didn't find any fibres in it..

Looking closely, it looks like sponge - kinda like a 1mm thick version of the other half's yoga mat, or a chocolate aero (only with smaller bubbles)
Soaking it in petrol made it expand and become a lot more rubbery, and burning it made rather acrid smell, like tar or plastic

Have you any suggestions for removing it, whatever it is? Should I try jetwashing it off, soaking it in something, burning it to a crisp?

Try contacting http://www.stripperspaintremovers.com, they have a lot of paintstrippers and strippers for removing other things. I found they were very helpful when I was looking for something to take a horrible textured paint off my house exterior. They recommended two products, I got samples of each and found the one that worked best.

 

[catlad]

I would make sure you do a sample before going for the whole roof.