Some kind of tar on the concrete floor in the basement

[Roger J]

Just ripped out a raised floor in the basement and under the plastic against the foundation, some type of tar has been smeared on. I plan to lay tiles, but how do I remove the sticky stuff from the floor?

 

[Roger J]

No one has any ideas? You can't just lay the tiles directly on the tarred concrete slab, can you?

 

[Jan-Å]

It was recently discussed in another thread, opinions were divided but I (and as I recall, the majority of the posts) believed that the tar should be removed before starting with the new floor.