What is this material?

[perfri]

Hi,

New to the forum. Learned a lot by reading so far but now I have a question. Started peeling away layers on the walls in an uninsulated porch. House from 1925.

The green should be the original. But I'm wondering about the black. Could it be something dangerous to remove? Asbestos, etc.?

Grateful for help.

 

[Stefan N]

Tretex.

 

[perfri]

Thank you for your reply, Stefan. Were they often black like in the picture? I thought they looked more like masonite.

 

[perfri]

Does anyone know what the black layers in the disc are?

 

[BirgitS]

Maybe some sort of asfaboard?
It was used as a windbreak board.

 

[perfri]

Thank you for your response. It's as if the disc has several layers of the black material. Alternated with what I perceive as more board-like.

 

[BirgitS]

As I understand it, asfabord used to be a treetex board with an asphalt layer. I have no idea if the asphalt was only on the outermost layer or if there were multiple such layers, and I also don't know how thick such a board is.

 

[perfri]

That sounds very likely to be as you say! Thank you Birgit!