Flat roof bodge

natnifnolnacs

I have a shed which is single course block. It shares a wall and roof with my neighbours shed, the roof is corrugated metal sheeting.

I had a few small leaks which I patched with bituminous paint, but now in cold weather I'm getting lots of condensation on the inside of the roof, meaning nothing can really be stored out there.

The roof was either never completed properly, or has degraded over time but there is only one strip of felt at the lowest point of the roof. The sheeting is in okay condition, as are the timbers, but the shed is unusable because of the condensation.

Now I know the best solution is to strip the sheeting, re-felt it properly and re-fit or replace the sheeting. The problem is, it's a shared roof and my neighbour is very reluctant to do anything with it as on his side all is fine. He doesn't really use the shed, so isn't that bothered.

So the upshot is,any fix I go for has to be internal. To give you a better idea, here is a picture of the roof. (You can see a light, but I've disconnected power for now due to the water)


So, what's my best option internally? Is there a product on the market designed for this? My only though is some plastic sheeting well overlapped, pulled tight and stapled to the beams but I think it would be very difficult to get that watertight...but if I ran marine ply sheets with the joins the opposite way it might work...

Any other suggestions?

Calahonda52

The requirement here is to raise the internal temperature of the underside of the roof.
Once you are satisfied that it is 100 waterproof, you might seal the overlaps on outside with flash band or similar, then take off the felt and put spray foam on the underside, but don't cover the frontside of the timbers, they need to breath.
You don't need a lot

Bonzo Delaney

A bit of a challenge but could be done if you take your time and have an extra pair of hands is .
Un screw all the sheeting on your side
By some breathable felt ( it wont tear)
Pull the felt from one side to the other ( left to right) between the rafter and the sheeting starting at the top and workin your way down to and over the party wall.
Re screw sheeting down
Then you could insulate between the rafters and screw some 12mm ply to the celing .
that'd tidy it up a bit

natnifnolnacs

Thanks for the advice. Sorry it's taken me so long to get back to this!

I think before I do anything, I need to dry it out properly and protect the beams. Realistically it'll be the summer before I tackle it, but at least now I have an idea what I'm going to do with it!