Peeling gloss paint on asbestos porch

[ChimesDesign]

I need advice please on preparing and painting the under side of a porch roof. Its been left to get in quite a bad state, with alot of peeling gloss paint. The area is 7m x 1m.

Its peeled right back in places to what Im told is asbestos. I planned to scrape back the loose, flaking paint (without disturbing the asbestos), then spot prime, undercoat and gloss. I think though that to do a good job its going to need filling or else it will be obvious where the paint has previously flaked away. Should I spot prime, fill, sand filler, spot prime again, then undercoat then gloss? Ive been advised by my local decorating centre to spot prime with dulux oil based primer sealer. But Im not convinced as Ive read that asbestos is alkaline based so I will need a alkaline resistant primer...or would bin zinsser primer do the job?

Also, Im not a fan of tetrion fillers. I usually only take on interior jobs and I use easifill. Which filler would you recommend for exterior fine surface filling, that really wont require too much sanding as I want to keep well away from agitating the asbestos.

Thanks
Laura

 

[jondecs]

Yes your right..
Asbestos should not be painted with solvent u/c gloss without first applying an alkali resisant primer sealer. The salts in asbestos react and push off paint like your experiencing now. Masonry paint is a good primer and might be cheaper than buying special primers like zinsser 123. ( not the bin )

Scrape offf loose, sand any surviving gloss (dont sand asbestos) and touch in all the bare asbestos with a thinned (with clean water) coat of masonry paint. then u/c and gloss . But I usually finish whole soffit with two full coats of masonry.. i.e dulux weathershild smooth/sandtex smooth.. I would not fine fill the flake edges. just two full coats might hide the craters. But if pressed I would use tetrion making sure to prime asbestos first and apply finely just at edges making sure i dont overfill ( a wet brush before it completely sets sometimes helps to blend )

good luck..

 

[ChimesDesign]

thanks jon, really helpful advice