removing a bitumen flashing from a roughcast wall

drlove

Hello
Could anyone help with removing bitumen from a wall?
When the old conservatory was taken down on the back of our house we were left with the remains of the bitumen flashing.
I have tried chipping and scraping, WD40, white spirit, then painted on PaintPanther. All I am doing is making a great mess and smearing it.
As the wall is roughcast it is not so easy to scrape off. Not keen on sandblasting or power washing the wall.

TELLIT01

A heat gun, such as used for paint stripping, would soften it but I think you are going to have great difficulty removing it without leaving an almighty mess. 

grumbler

TELLIT01 said:

A heat gun, such as used for paint stripping, would soften it

I'd do the opposite - wait for winter and some frost.

clive0510

you're going to struggle with that. as the other poster said a heat gun may do it. does it go all the way up the wall to the roof? is the wall behind it plain brick or is it rendered?

grumbler

Removing the bitumen can be done easily without a heat gun.

It's the remaining stains that are hard to remove. A heat gun can help only if it burns it completely, not just melts. I don't think that it can do this. Acetylene torch maybe?

drlove

Thanks for your replies.
The problem, apart from bitumen being quite nasty stuff, is that the wall is roughcast or like pebbledash. It's a strip about 4 metres wide across the back of the house where there was an old conservatory. Somebody before me applied bitumen and foil tape as sealant, or flashing. 
I may just have to smear it and then paint over with something like Zinsser Bulls Eye Primer?

shiva_fazeli

Bitumen has a very high adhesion; But it is recommended to use paint to cover it.

chrisw

You might do better with a tar remover such as
https://www.chemiphase.co.uk/tarsolve-bitumen-cleaner-tar-remover/?sku=SKU-319E77D8&gclid=EAIaIQobChMIhOaIt_mh7AIVV-DtCh2GJgNgEAQYAyABEgIJvfD_BwE

Screwfix also do one, the reviews aren't brilliant but might be ok for what you need

https://www.screwfix.com/p/zep-commercial-tar-bitumen-remover-5ltr/5884X?tc=JT7&ds_kid=92700046638549236&ds_rl=1243318&ds_rl=1241687&ds_rl=1245250&ds_rl=1245250&gclid=EAIaIQobChMIhOaIt_mh7AIVV-DtCh2GJgNgEAQYASABEgJqVvD_BwE&gclsrc=aw.ds

Mistral001

grumbler said:

TELLIT01 said:

A heat gun, such as used for paint stripping, would soften it

I'd do the opposite - wait for winter and some frost.

I agree with this.  Do not use solvents or heat.  That will just make the bitumen penetrate more into the roughcast.  Wait until there is cold weather and chip it off with a hammer and chisel.