Distance for roost from the wall

[Cinderblock]

I use a poop board that's 24 inches deep and the roost bar is in the middle. So 12" away from the wall, I don't get any poop on the wall.
View attachment 2067372

What is the black stuff on the wall and floor? I like the way your coop is designed. We are looking for ideas for our new shed.

 

[rosemarythyme]

What is the black stuff on the wall and floor? I like the way your coop is designed. We are looking for ideas for our new shed.

It's Black Jack 57, I also use it on my wood floor and partially up the wall to seal and waterproof the surface.

Here's blackdog043's article on it: https://www.backyardchickens.com/articles/black-jack-rubr-coat-57-for-your-coop-floor.75145/