A leaking shed roof is bad news – not only for anything you may be storing in it, but also for the shed itself (any damp will affect the floor and walls too). Just like a fence, the two main enemies for a shed roof are the wind and rot.
My first step when asked to re-felt a shed roof is to establish how far the damage has gone. If the roof is an OSB board and has been very wet, it is likely that the roof will also need to be replaced – if this is the case I will always advise you of this need. A tongue and groove board roof often survives better and it is possible to go straight to the re-felting process.
In the re-felting process, I remove the old felt and replace with a new, heavy-weight felt. I prefer to fix the new felt with both adhesive and nails as it gives a better seal. This also helps to prevent the wind getting under the joins and lifting the felt again….. and this is important as we seem to live in a particularly windy area!
To finish the job, I replace the trims (using new ones if they have gone beyond repair) which makes the roof look better and gives a further seal to the edges. After that, your shed is water-tight and ready to go!