create a pitch on a flat roof?

[jswasky]

I have a 70's model flat roof mobile home that needs the roof replaced. Would it be possible to create a pitch? If so, what would be the best way to accomplish it? The existing roof has a lot of dips to it. The reason I ask about a pitch is because I have another similar home that we put a metal roof over and it still leaks. Thank you for your input!

[canman47]

I was faced with the same problem last year. My 1973 with a low pitch roof was leaking and I thought I could put a ridge board up and make a higher pitch metal roof. After a lot of research and consulting the answer was no. My existing frame could not handle the extra weight. I was looking at doing a roof-over where you build a separate roof over the whole thing but that was complicated and too expensive for me. I ended up hiring a company to install a vinyl roof over foam board. It's quiet, warmer and I don't think it can ever leak. It's guaranteed forever. It cost $7500 which was about half what the roof-over was looking like.

[Norm Frechette]

i witnessed 2 homes in the park i live in that had their flat roof converted to pitched ones. it can be done.

http://www.ehow.com/how_2086295_pitch-flat-roof.html

[JD]

Norm, the link you offered was a very generalized overview of adding pitch to a stick built home with a foundation. Even then, without an engineer's report and plan, you are shooting in the dark and taking your chances. Adding additional lumber and sheathing to a flat mobile home roof is taking those chances to extremes. That being said, I have seen mobile homes with added on shingles roofs that seemed to be holding up well. But I have also seen many homes ruined by adding on this extra weight.

Older mobile homes with semi-flat roofs almost always have 1x2 trusses. Any weight distributed to the middle portion of that truss will transfer it's weight to the bottom cord of that 1x2 truss, making it bend and warping the ceiling. I have seen them sagging low over 6", but just one inch is noticeable. A worse case scenario would be the warping lowering the pitch to the lower half of the trusses, allowing rain to blow up the shingles or in the case of metal and rubber roofs, it could cause ponding.

I have also seen many older homes with these trusses and badly warped ceilings, that did not have and added roof to the existing. Usually the tops of some trusses have been broken by people not being careful on top of the roof or the trusses just got old and wore out.

Canman's rubber roof installed direct to the existing roof is an excellent option.

[Greg]

There is also the option of a free standing pole barn type roof not attached to the home.

Greg