Roof Structure on Top of Previous Roof

[Kenny Rigler]

Hey Guys-

On this manufactured house they came back and build another roof on top of the current one. I didn't see any evidence of problems on the walls around the home, but I wondered about whether the original walls were designed to carry that much of a load. Just curious to see what you guys thought...thanks.

Kenny

[gbeaumont]

Originally Posted by krigler

Hey Guys-

On this manufactured house they came back and build another roof on top of the current one. I didn't see any evidence of problems on the walls around the home, but I wondered about whether the original walls were designed to carry that much of a load. Just curious to see what you guys thought...thanks.

Kenny

Not good, roof-overs are supposed to be independent of the original structure for support, the wall systems were not designed for those additional loads.

Regards

Gerry

[Larry D. Kage]

What Gerry says is typically correct.

Were you able to see, or did you get a picture, of the truss bearing points/area?

I have seen a roof system on a manufactured home, designed by a SE, that was headed off above the top plates and the new roof system rested on that.

That one looks pretty straight. How long ago was the roof added?

[Brian A. MacNeish]

Originally Posted by krigler

Hey Guys-

On this manufactured house they came back and build another roof on top of the current one. I didn't see any evidence of problems on the walls around the home, but I wondered about whether the original walls were designed to carry that much of a load. Just curious to see what you guys thought...thanks.

Kenny

A truss system like that would be designed by a structural specialist either an architectural engineering technician or maybe a civil structural engineer. As such, they would've (should've) taken the loads into account.

If it's a standard 2x4'' at 16" OC wall sitting on a concrete foundation, the extra roof load should be no problem. That wall supports 1+1/2 stories (second story floor plus attic 1/2 story) plus the roof in many 2+1/2 story houses with no problems. Up in Canada and the northern US, it also must carry wet snow loads plus the house!!

May look much worse than it is!

[Kenton H. Shepard, CMI]

It requires calculations to determine if it's safe. Recommend a structural engineer.

[Randy L. Mayo, PE]

Kenny

In theory this new roof could be added with out overloading the wall studs. The wall is still carrying the same live load just needs to carry the extra dead load of the new roof. Typically wall studs are spaced to accommodate the attachment of siding, gypsum boards, etc and have significant reserve strength for vertical loads. With that said the devil is in the details and the new roof connection points would have to be analyzed and in that process enough data would be available to check the load capacity of the walls. Whew.... that was the long answer.

The short answer is the current owner should show proof he had sealed engineer plans and a certification from the engineer and/or the installer that the roof was constructed according to plan. Anything less would warrant a statement in your report to have a SE review.

[Kenton H. Shepard, CMI]

You're right, Randy!

[Kenny Rigler]

Originally Posted by lkage

What Gerry says is typically correct.

Were you able to see, or did you get a picture, of the truss bearing points/area?

That one looks pretty straight. How long ago was the roof added?

Larry-

No, I didn't get a good look or pic of the truss bearing points as there was pretty limited access. And no, I'm not sure how long ago it was added as I was the only one at the inspection...but I'll ask. This was a unique situation in that the wife, who ordered the inspection, was getting a divorce and keeping the house. I guess to re-work the mortgage the lenders wanted an inspection.

Originally Posted by rmayo

Kenny

The short answer is the current owner should show proof he had sealed engineer plans and a certification from the engineer and/or the installer that the roof was constructed according to plan. Anything less would warrant a statement in your report to have a SE review.

Randy, I agree. I'll dig a little deeper with the owners and see what they come up with and otherwise will recommend review by an SE. Thanks.

[Sean Fogarty]

My redneck inlaws did that to their trailer and 20 years later its doing OK