Shed Roof Leak

pebblebeach8

Hoping someone can advise. I had my shed roof re-felted last year, but because the middle of roof has sunk slightly (where water was leaking the previous winter and not spotted until Spring), water is pooling in puddles in a couple of places and some water is still leaking into the shed. I have found two products - Thompson's Emergency roof repair mastic or Thompson's 10 year Roof Seal - but am unsure which one might be best to use?

Does anyone know if it would it be best to use the repair mastic where the water is pooling or seal the whole roof with roof seal? Would really like to get sorted before Winter sets in. Thanks

EssexExile

The best thing to do would be to stop the water pooling, by restoring the proper fall of the roof, then cover it with a rubber roofing system.

Aylesbury_Duck

I agree. It needs fixing properly before winter. Before it gets any colder and wetter, get the felt taken off, the sagging roof boards replaced and the felt put back on. What you're proposing is treating the symptom, not the cause and will perhaps fail in the depths of winter when doing a proper repair will be much more unpleasant.

TELLIT01

Assuming only one section of the roof boarding has sagged it won't be too expensive to replace, and you will have a much better end result than applying any form of mastic or similar.