In message , Vincenzo
writes
hi, can you help me? i need to replace my flat roof on the bay. it is
felt.
can you suggest materials to use? someone suggested torch on felt?

Torch on felt isn't really something to try DIYing, if you want to use
felt you can get self adhesive systems- Wickes used to sell something.

Lead or Zinc as others is said is the best, if you don't feel up to that
a more durable alternative to felt is Butyl rubber.

http://www.midland-butyl.co.uk/

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Chris French, Leeds