A friend of mine has asked me to re-felt his shed roof. His shed/workshop is 18'x8' with a pent roof. I have only ever felted a an 8x6 shed before, and I just walked into wickes, bought some felt, and nailed it on...Wanting to make a good job for a friend, I looked around a bit more carefully and I notice that there is a very varied choice of roofing felts available. Can anyone tell me the best stuff to use for a good long life and ease of fitting? Any other tips, to make the job go well would be appreciated too. Thanks in advance. Flashbang..