I have recently tanked my basement. The tanking went well. I gave it a few weeks to dry out and the walls were bone dry. I then used a combination of board adhesive and membrane fixings to fix foil backed celotex insulation boards directly on to the tanking. I've since dabbed plasterboards on top and skimmed all of the walls. I'm having drying problems. I cut a square out at the bottom of one of the walls and the board adhesive onto the tanking still hasn't dried. I've put some heaters down there to warm the place up but it's still not drying out. It's been on for a few weeks now. Any thoughts?