We have an enormous water stain on our kitchen ceiling. Our builder told us that it was caused either by faulty, old rendering and/or worn pointing on the upstairs windowsill which is build of bricks. Builder came 5 days after the agreed date and of course with the torrential rain we had the problem become quite desperate. The stain is very light brown, the edges are a lot darker and the stain is increasing but very slowly; about 1/2 inch per day. Am I right in thinking that it will take months for the ceiling to dry out? Thanks in advance for any answers.