Shed Roof Leaking

[fouxdafafa]

I recently replaced the felt on my pent shed roof. It was looking the worse for wear and also there were damp patches on the inside of the roof. I was reasonably happy with my re-felting at the time - I used 3 strips of felt, overlapped them properly and clout nailed them. Over the last few months ripples have appeared in the felt, so it's looking a bit cr@p and the water doesn't run off so easily and there are still damp patches inside. I'm assuming the rippling is due to the felt stretching due to the amount of rain we've had. I can't really explain the damp patches. The only thing I can think of is that it's leaking through the clout nails in places. So, I'm contemplating (when we get a dry couple of days) trying to remove the ripples be removing some clout nails and smoothing it out, then re-nailing. I would also re-nail in the regions where the roof is leaking. Obviously I would need to do something about the existing nail holes in the felt. Can anyone suggest the best way to do this and/or any product I might use? I'm thinking of something bitumen based but I've also seen Ronseal Isoflex which sounds really good. I really don't want to re-felt the whole roof again. Thanks.

 

[foxhole]

I only use clouts on the edges, seams should be glued together to ensure watertight.

http://www.toolstation.com/shop/p73...=26799262103&gclid=CJ_unt2ugrwCFeLHtAod8G8AVQ