Ok, cheers. I gather the stuff is basically tar but it didn't really occur to me that is might not be easy to just cover over down the line.
I'll put a bit of cardboard down today and check that tomorrow as suggested to see how that comes up and will report back. The damp is definitely worse...
Please bear with me if there are lots of silly questions here -- I'm a novice DIYer anyway and this is totally new territory for me! I struggled with which forum to drop this into, too, so hopefully this is ok...
I have a late 19th-century back-to-back terraced house, which has a moderately...