Replies

1. 
   oldhand | Sep 01, 2011 08:49pm | #1

   best be cautious....

   With newer mobiles sometimes the original manufacturer can help with loading advice. If it is an older one less likely...

   Odds are good the original roof is not designed for any  loads like a whole new roof.

   I have seen it done successfully with trusses supported by treated post and beam [pole frame]. Posts are located outside the mobile walls.

2. 
   Piffin | Sep 01, 2011 11:16pm | #2

   In areas where this is needed, it is usually because of snow load.

   But when you need to sed snow before it gets too heavy and crushes the mobile home, the extra weight of the framing and shingles is a danger in and of itself.

   So the only way oi  have seen it done ( and only way I know of that is alowed in these areas) is to set posts alongside thje mobile home to spport the roof load and the snow that lands on it.

   If that is not you reason for the added structure, I would need to know two tings before proceding.

   First is whether the maker of the home built it with enough integrity to handle the added weight on the walls

   Second is how the walls and roofing framing are detailed at the perimeter. I would most likely set a 2x8 running upright around perimeter at top of walls so the top of it is 1/2" above the roof edge and use structrual screws  to fasten it thru the skin to the framing. This is where knowing the framing detailing comes in. Then I would use hurricane clips to set the rafters to this

1. 
   DanH | Sep 02, 2011 06:32am | #3

   I've seen it done because the roof leaks.  And it also gives one an opportunity to add a bit of insulation, particularly to reject heat.

1. 
   Piffin | Sep 02, 2011 05:25pm | #4

   Once we have some idea why the OP wants this and where he is, we could actually be hel;pfull instead of speculative

1. 
   justbugme | Sep 05, 2011 02:51pm | #6

   I'm in northern Canada. "Lesser Slavelake, Alberta. And the reason for the roof is the trailer roof leaks in many places. Your ideas are interesting so far. I'm leaning toward the 2X8 around the periimiter idea. Still would like to hear others.

1. 
   DanH | Sep 05, 2011 03:51pm | #7

   As I understand it, many of the older trailers are actually relatively standard wood stick framing under the skin.  The trick is to locate where the framing members are so you can attach to them and have the load bear properly on them.

   Since you will be adding a new roof you should be able to safely cut small holes in the existing roof to install blocks on top of the old framing to support the new plate, if it turns out that there is too much "void" between roof and the framing below.  I'd suggest anchoring the new plate with Timberlok screws (if you need really long screws) or GRK screws (which are readily available up to about 6").  Depending on the thickness of the framing (may be 3/4" in places) you may need to open a wall or three from the inside and install blocks to receive the screws.

2. 
   Piffin | Sep 05, 2011 07:46pm | #8

   Dan, I have owned and worked on mobile homes. They are far from standard framing!

3. 
   DanH | Sep 05, 2011 09:08pm | #10

   Well, some of the ones I've seen were (more or less) conventionally framed.  (Though at the time I wasn't interested enough to note how close to "conventional" they were, in terms of wood dimensions, stud pitch, etc.)  Don't know if it was a representative sample or not.

3. 
   florida | Sep 02, 2011 05:25pm | #5

   Around here we usually use aluminum roof pans. Screw down some alum 2" X 2"s around the edges, frame up an alum 2" X 6" ridge and start laying pans. Cheap, fast and very lightweight. I've had one old mobile with that roof on it for over 20 years and never had a problem.

1. 
   Piffin | Sep 05, 2011 07:48pm | #9

   But you don't have to contend with a snow load in FL

1. 
   DanH | Sep 05, 2011 09:18pm | #11

   Unless the eaves are excessively wide, the new roof would not change the snow load, and would, in fact (due to the slope), tend to reduce it.  Plus the load would be more concentrated on the structural members of the outer walls, vs bearing on the relatively weak ceiling "joists".

1. 
   Piffin | Sep 05, 2011 11:02pm | #12

   stop and think before you type, Dumbass.

   A pan spanning half the width of the mobile from a raised ridge to the wall with no intermediate support is going to be broken, bent and done keeping water out after the first snowfall in Northern Canada

1. 
   DanH | Sep 05, 2011 11:05pm | #13

   What the hell are you talking about?  Just how does a conventional roof have "no intermediate support"??

4. 
   BossHog | Sep 06, 2011 06:29am | #14

   One time way back a truss company I worked for built a whole bunch of 14' scissor trusses for just exactly that. They put down a 2x4 plate over the existing walls and set the scissor trusses on top.

   I don't recall how they handled the soffit and tied it back to the trailer.