Right, Shedxperts of yacf - Bring me your wisdom.
I have inherited a decent sized shed with my new dwelling. The first thing I noticed was that water was pissing in every time it rained, the roof materials were sodden and there was considerable mould growth on the walls inside.
I stripped the old felt off in December and made a temporary covering with a big sheet of DPC. Much to my delight, the roof timber has recovered quite well and is now fully dry. I have replaced a load of the shiplap boards on the rear that were rotten and given it a thorough drink of cuprinol. The shed is worth another turn.
The current roof structure is a series of boards about 100mm wide by 10mm thick. They are anything but level with one another and there is some bowing in the very middle of the roof. My idea is to attach some big sheets over the top and felt over them instead.
To Ply or to OSB? And then what thickness? I don't want to add too much weight, so I was leaning towards 5mm ply, but i'm not sure it'll be stiff enough.
Then onto the felt. Any old felt? Nail or glue-on? Any other membranes underneath?
Over to you. Any ideas welcome. I don't want it to be a massive job.