Roof Leak, Ceiling Damage

[Wildpath]

I recently bought a piece of land that had an older mobile home on it. I originally thought it was worthless because of all the damage, but I have begun fixing it up. The building was never levelled, and had taken on some water damage due to a leak in the roof. The roof has been patched up, and hopefully all is good there, but I have now started working on the interior.

The interior showed quite a lot of mold once I removed the ceiling panels, so I took out the insulation and saw that there is some damage to the frame. When I took the insulation out of the ceiling I noticed there is a black particle board type material against the metal roof. I do not know what this is, but I am wondering what I can do about it. I do not want to redo all the rafters and start fresh, so can I just cut it out and insulate right against the roof?

So to summarize I have the following questions:

1) What do I do about the black board next to the roof?
2) After I replace the affected rafters that are rotted, can I insulate, throw up some poly for a vapour barrier and then cover it with ceiling panels?
3) The ceiling sags quite a bit. I don't care about this too much as I imagine I'd need to replace all the rafters and basically begin fresh. Is there anything serious to worry about the sagging?

Thanks all

[Greg]

I have never heard of underlayment between the metal & rafters. Are you sure it is not some type of vapor barrier? Pictures would help.

The description you are giving tells me that you may be time & money ahead by doing a total renovation. If mold is involved I would take it down to the studs, rafters and floor joists and rebuild from there. Masks are a must since you don't want to be breathing mold spores.

Greg

[Wildpath]

It could be some type of vapour barrier. If I had pictures I would post them, but I have to do the work in large chunks as its far away from road access. I'm talking about snowshoeing 1/2 mile off the road to get there. Ya, that's a challenge, lol.

I am stripping it down to the frame in the affected area and in some cases replacing part of the frame where it has shown signs of rot.

I think what I'll do is cut out the black board where possible in the affected area and then insulate and put the poly vapour barrier right against where I put the ceiling panels. Is that a decent idea? I am not counting on this as a long-term shelter, but maybe for a summer or two since I'm not staying at the property in the winter - thus the long snowshoe trek to access it.

Thanks for the help Greg!

Mike

[DaleM]

Some manufacturers built their roof structures with buffalo board/black board in between the rafters and metal roof to quiet them down. There is some insulation value as well. I would leave as much of that in place as possible. Make the new rafters from either 2x6 or 2x8 material, install those 16" on center then insulate and install a vapor barrier.