Bitumen paint

[Pford75]

Several of our outbuildings and some of our walling are built in clay lump. This clay lump has a top coat of what looks like bitumen paint. We understand from neighbours that it used to be applied by a large tank sprayer system (there is a lot of surface area) and has been like this for many years.

Now, obviously i'm aware of the need for breathability and that bitumen paint is nothing of the sort. However, none of these buildings are showing signs of damp and we're not in a position currently to have it all stripped off and lime rendered. In small patches, (most the size of a 50p piece and none larger than a hand) the bitumen paint is going thin or coming off.

What are the views on how best to treat? I've considered applying small patches of lime render, but worry that they will not take well (especially around the edges on top of the bitumen paint) - coupled with that, I will be left with with white(ish) patches against the remaining black.

If I am going to replace 'like for like', then can anyone recommend a sprayable bitumen paint?

 

[Flyfisher]

Is this the same sort of 'paint' that seems to be applied around the base of many rendered houses (around these parts anyway)?

I have the same issue and also wonder about the best solution.

 

[Pford75]

Is this the same sort of 'paint' that seems to be applied around the base of many rendered houses (around these parts anyway)?

Absolutely. On some of my outbuildings, the black stuff is only on the few courses of bricks at the foot of the wall with a lime render on the clay lump above...but on some walls, the black stuff covers the entire wall. Maybe it's a Norfolk thing?