New Roof on Trailer and Covered deck

[flint]

I have a 1971 Beverly Manor 12 x 50 mobile home with a 12 x 24 covered deck with about 1:12 pitch roof. I need to re-roof the trailer which I'm thinking on putting the metal roof described in your Mobile Home manual. The roof over the covered deck is rolled roof I believe over plywood sheets. The wood has rotted, so I will need to replace this roof also. I plan to remove all of the rotted wood and leave only the joists. The roof on the covered deck is a a little lower than the trailer roof. Is it possible to extend the metal sheets from the trailer onto the joists of the covered deck without raplacing the plywood? If this is not possible, please advise best system I should use for this low slope roof. I know nothing about roofing. Any help would be great!

[JD]

If you do not have a lot of building experience, I would definitely recommend using proven plans like the one in the Mobile Home Repair Manual or the metal roof instructions available through the Books & Parts link above.

Covering rotting wood is never the best choice, but to answer your question, the heavy gauge corrugated roofing and some other metal roof panels do not require plywood sheathing. 2x6 framing should be sufficient for these products. Check with your products spec sheets or product rep to be sure sheathing is not needed. But the joists should be running perpendicular to the roof panels instead of the same direction. You may be alright with adding blocking at 16" or 24" o.c. (depending on specs).

If it were me, I would work the main coach roof and deck roof as separate units. I would roof the deck first, totally sealing the panels at the main coach flashing, then install the roof on the main coach, allowing a little overhang over that flashing area. I find it easier to control water flow and to perform maintenance by having a "step down" from one roofing plane to another. I have seen roofs where the main coach roof panels extend over add-on rooms and porches that seemed to be working fine though, but getting a good seal between the home and the deck roof can be a problem sometimes. You have to be sure that that joint is fully supported though.

JMO
JD

[dinotoad]

Be sure to relevel the home before you proceed.

When my home was releveled it pulled out the porch supports near the home and now I need to deal with that. If they had releveled before building the deck and porch roof, it would not have been an issue.