Odd Infill Roof Framing - InspectionNews

Bruce Breedlove · #1 (**permalink**) 12-21-2007, 02:30 AM

This is new construction. The infill framing where a gable ties into the main roof was framed with rafters and a ridge board. The framers added numerous 2X4 posts along the rafters down to the roof decking below (above the trusses). The posts were nailed to the rafters (2 nails) and toenailed (2 nails) to the decking. The bottoms of the posts are squared off (not cut to match the slope of the decking).

Apparently this framing was passed by the local building inspector. I don't see the need for the posts. Plus I doubt the underlying trusses were designed for the additional point loads of these posts.

How would you report this?

Aaron Miller · #2 (**permalink**) 12-21-2007, 08:33 AM

Bruce:

Green tagged I assume? How about IRC 301.1 and 801.2?

Aaron

Bruce Breedlove · #3 (**permalink**) 12-21-2007, 12:11 PM

Aaron,

Both those codes pertain to design. I have the following limitation in my report: "· Engineering or architectural services such as calculation of structural capacities, adequacy, or integrity are not part of a home inspection." I'm not concerned about the rafters so much as the trusses below that are being loaded with point loads that I suspect the truss manufacturer did not design for.

Would you recommend the builder provide documentation that the trusses can accomodate the point loads from these posts?

Aaron Miller · #4 (**permalink**) 12-21-2007, 01:11 PM

Bruce:

Certainly.

Aaron

Bruce Breedlove · #5 (**permalink**) 12-21-2007, 01:41 PM

That's exactly what I did.

Jerry Peck · #6 (**permalink**) 12-21-2007, 06:35 PM

Wonder if the framer knows he left all the 'temporary' bracing up?

Yeah, that a definite 'Have a structural engineer verify ... '

Bruce Breedlove · #7 (**permalink**) 12-21-2007, 09:35 PM

Quote:

Originally Posted by Jerry Peck

Wonder if the framer knows he left all the 'temporary' bracing up?

Interesting. I had not thought of that.

charles buell · #8 (**permalink**) 12-22-2007, 10:52 AM

I have to say that the "forest" of supports whether temporary or intended to be permanent really doesn’t load the area of infill any more than any properly in-filled area. These T or L shaped houses often have one roof laying over the top of the other roof and the lapping area is merely in-filled and the adjacent roof carries the load of the in-filled area. You could argue that the forest of posts helps spread the load but I really don’t see how it creates any structural concern. That said the adjacent roof trusses have to have been designed for the adjacent roof overlay----and you will rarely see any design change in the adjacent roof trusses to compensate for a "typical" overlay

Bruce Breedlove · #9 (**permalink**) 12-22-2007, 11:47 AM

Quote:

Originally Posted by charles buell

That said the adjacent roof trusses have to have been designed for the adjacent roof overlay----and you will rarely see any design change in the adjacent roof trusses to compensate for a "typical" overlay

That's it exactly. The underlying trusses will see roughly the same loads as they would without the overlying roof (plus the dead load of that overlying roof structure). BUT, instead of the loads being distributed over the roof surface, these loads have been converted to point loads on the trusses. Trusses typically must be designed for point loads such as this.

That said, I doubt the infill framing will overstress the top chords of the underlying trusses. But that is not a call that I want to make.

Jerry Peck · #10 (**permalink**) 12-22-2007, 08:33 PM

Quote:

Originally Posted by charles buell

I have to say that the "forest" of supports ...

I see I'm not the only one who thought of that as a "forest" ...

My thought was 'My gawd, that framer can't see the forest for the trees.'