whats the best way to seal cracks in a roof to make it watertight please?

Never heard the name 'bitchamine' before, but just read about it in a book by Noah Boyd ('Agent X', 'The Bricklayer'). I've seen it demonstrated on 'This Old House' - recommended by good old Norm and Tommy, and I believe 'Home Time'. Works very well if applied before the first rows of shingles/shakes etc., on to the bare wooden roof to prevent ice dams from damaging the roof/causing leaks etc. The nails are sealed as soon as they puncture the membrane. In the book above it is described as 6 feet wide, but I thought that 3' would be sufficient, but of course depends on location I guess (heavy snow loads and melt/roof pitch etc.) Not sure that it would be any good to repair an already leaking roof - except of course if the roof is stripped and new shingles/shakes/tiles installed. Only recourse for above problem may be a new layer of shingles over the old ones, but this is merely a 'band aid' solution and not guaranteed to solve the problem.

Ed Wills
March 2011

What you do need to do is to say what is he type of roof! Tiles, Slate, or Felt [flat roof].? You will then get constructive replies.

Bob
May 2009

Do you mean bitumen? If you do, this is a liquid sealant that will only fill tiny gaps and cracks. For larger repairs, you need a product such as Flashband which is like a self adhesive tape, 100mm, 150mm or 225mm wide. Its pitch on one side, and aluminised on the other. Flashband is a trade name - but builders merchants know what you mean if you mention flashing tape. Its as good as it gets!

John
May 2009