Remodel rafter config. - InspectionNews

Eric Shuman · #1 (**permalink**) 08-16-2007, 06:04 PM

This was a remodel inspection. They basically added a slab for a couple of rooms and took part of the roof off to re-frame the roof to accomodate the new areas.The old roof was a truss system and the new portion was stick framed. The trusses are not used in the new portion but where they tied the new new roof in with the old, they attached (scabbed onto) some of the new 2x8 rafters to the old trusses without the new rafter ends bearing on the exterior walls. See photos below. Note the 2x4 brace under the rafter near the end. I could not determine if this brace went to a bearing wall, but not all had these braces anyway.

Some trusses were chopped up and although they are no longer effectively holding up the roof in this area because the rafters have been installed, the bottom cords are still used as ceiling joists. I'm thinking that this may result in problems down the road.

I don't know whether an engineer was consulted for this design. It does not look engineered to me.

I know that the IRC says this about rafter bearing:

802.6 Bearing.
The ends of each rafter or ceiling joist shall have not less than 1 1/2 inches (38 mm) of bearing on wood or metal and not less than 3 inches (76 mm) on masonry or concrete.

Several rafters are configured like the one in the photo or similarly. The contractor did pull a permit but it hasn't had a final yet. I find it difficult to believe that this is acceptable or that it got by the B.O.

Any thoughts?

Thanks,
Eric

Jerry Peck · #2 (**permalink**) 08-16-2007, 06:13 PM

Ask to see the engineering for those truss modifications.

Whether or not it did, or will, get by the city, those trusses *are not supposed to be modified* unless accompanied by engineering which states what to do where and how to do it.

Then, you will want to get a letter from the engineer which states 'yeppers, it was done as I showed it should be done'. That way, the engineer is taking all of the liability for saying 'It's okay.', not you.

Robert A. Kuzmick · #3 (**permalink**) 08-16-2007, 06:36 PM

That 2x4 brace is there to bring the new rafter up to the bottom of the plywood roof. The old trusses had a 2x4 underneath them acting as the bottom chord and a 2x4 on top acting as the rafter. tHE NEW looks like a 2x6 or 2x8 which wouldn't bring ot down to the bottom wall plate, so the scabbed it with a 2x4. Believe me I know. I just bought a camp that had the same issues.

Jim Luttrall · #4 (**permalink**) 08-16-2007, 07:30 PM

I agree with Jerry, they screwed the pooch when they cut the truss and then scabbed on. They need to either use the truss un-modified or get rid of it and stick frame it correctly. There is no way THAT is an engineered fix. Call it out and let them document it like Jerry said (they can't - IMHO) or tear it out and fix it.
Jim

Bruce Breedlove · #5 (**permalink**) 08-16-2007, 08:25 PM

There is a bridge in Minnesota lying in the Mississippi River that collapsed when a critical part of its truss failed. The trusses on this house have had major modifications. (Butchered is more like it.) If the modifications were not done properly the trusses could (will) fail. The top chords are no longer tied to the bottom chord meaning these are no longer trusses. Now you have 2X8 rafters and 2X4 ceiling joists. That would never fly.

A structural engineer can determine if these modifications are acceptable. My money is on "they are NOT acceptable".

Jim Robinson · #6 (**permalink**) 08-17-2007, 06:41 AM

We did almost the same project about six years ago when I was working construction. We cut the top chords and left the bottom for the ceiling. We had TJI floor trusses parallel to the bottom chords that we nailed the chord to. It worked fine, but it was probably supported a lot better than what is shown in the photo. There should be an engineer involved.