Cleaning burnt on tar from inside chimney - then painting

[David]

Everywhere I look at this chimney project there are more questions.

Where the fireplace opening meets the chimney above there is a lot of old tar burnt onto the concrete and brick.

I would like to stabilise the whole thing, to stop little bits of mortar falling off, and preferably paint the whole thing as well.

The first problem is the tar - can I clean it off? Can I paint over it without the paint just peeling off?

Cheers

Dave R

[harryagain]

You can chip/wire cup brush in angle grinder most of it off. If you then give the surface several coats of PVA & water is will seal the surface & then paint/render. (Render will need to be mixed with PVA and water.)This will stop the tar bleeding through paint etc and get good adhesion.

If it is a rendered surface with tar on, probably best to chip all off right back to brick/concrete work &so tatally get rid of it

[ARW]

It will need sand blasting