Polish on tar adhesive

[oscarwww]

Currently renovating a 60s bathroom. They've used tar paper as waterproofing under the tiles. I need to smooth the wall to prepare it for waterproofing, does type C plaster stick to the black adhesive?

 

[nino]

No, you need to remove that, remember that there might be asbestos in the glue.

 

[oscarwww]

No, you need to remove it, remember that there could be asbestos in the glue

Won't gypsum plaster adhere otherwise? They've tiled on tar paper and made it adhere to that, so wouldn't the tile adhesive otherwise adhere to the glue?
I want to avoid spreading it if I sand it off.

 

[nino]

Actually don't know, but a bathroom renovation is so expensive that I wouldn't take a chance.

 

[MathiasS]

No, it doesn't stick to that, I have the same mess on a wall in the garage myself (it's an old outer wall) and I'm going to rent a concrete grinder before plastering the wall. The plaster has come off everywhere this goo is.

 

[neo11]

If you apply gypsum's expensive pink primer first, I'm convinced weber gipsbruk will adhere to it.

 

[MathiasS]

----it takes a few minutes to remove with a concrete grinder so I'm not going to take my chances.....

 

[Ludde Jakobsson]

Can't remember the percentage... but at least 60% should be removed to avoid double moisture barriers... i.e., the old wall should be able to breathe.