IRC 502.6.1 purpose
IRC 502.6.1 purpose
(OP)
Does anyone know the history - reasoning - purpose behind IRC section R502.6.1 - Opposite floor joist over interior supports lapped 3"? In this case there are 2x8 floor joist spanning 8' to 9' butt together over a double LVL beam and NO wall above it. A home inspector is saying telling a contractor it doesn't meet code. Granted it doesn't, but I don't see where its critical. There is adequate end bearing, and 3" isn't long enough of a lap to consider it a continuous member. LTB won't be a factor because continuous solid blocking is installed. I plan to show have a 2x4 scabbed across the butt joint, but really don't see the need for it. I've ran across this same issue a few years ago when an insurance company denied a claim after a wash machine ran over, and the floor sheathing buckled claiming it wasn't built to code. Appears to be an in the IRC because it's always been there, and nobody has a motivation to remove it. Any thoughts someone is willing to share will be appreciated. Thanks,





RE: IRC 502.6.1 purpose
That's just my $0.02
RE: IRC 502.6.1 purpose
1. To provide enough end distance so the individual joists can be toe nailed to the wall top plate, with the intention of minimize the tendency of the joist to split out at the end, and
2. To provide enough distance to maintain joist bearing in a seismic situation should strapping between the joists not be used, and a minimum of shear attachment to the wall top plate. This should not be a problem in a low seismic area.
Mike McCann, PE, SE (WA)
RE: IRC 502.6.1 purpose
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: IRC 502.6.1 purpose
The commentary to that section of the code states the the overlap is " to provide a concentric application of load the supporting beams or girders...". Of course, that assumes the reactions are symmetrical. KootK is correct that the IRC is prescriptive. If you supplied calc's showing sufficient bearing exists I would think the problem would go away.
Regards,
DB
RE: IRC 502.6.1 purpose
Garth Dreger PE - AZ Phoenix area
As EOR's we should take the responsibility to design our structures to support the components we allow in our design per that industry standards.
RE: IRC 502.6.1 purpose
RE: IRC 502.6.1 purpose
The greatest trick that bond stress ever pulled was convincing the world it didn't exist.
RE: IRC 502.6.1 purpose
RE: IRC 502.6.1 purpose
As for lapping floor joists......basic reason (as noted in other posts) is adequate bearing. Better resistance to overturning is another consideration, since all beams must have adequate lateral bracing at supports.
Based on my understanding of the role of home inspectors......which almost all even include in standard verbiage with their reports that tends to greatly exceed any written descriptions of observations.......is that they are not supposed to checking code violations anyway. They should be checking general condition to determine if there might be damage or a grossly unsafe condition such as a girder completely cut through by some exuberant HVAC installer.
John F Mann, PE
www.structural101.com
RE: IRC 502.6.1 purpose
Another thought I had is that the solid blocking that is often typical over beams or bearing points is harder to achieve without the overlap. If the joist butt up and no overlap is present there is a good possibility that the solid blocking between joists will block one set of the joists and not the other set given the tolerances of most framers. Requiring the overlap ensures that this blocking is working positively for both joist sets.
A confused student is a good student.
Nathaniel P. Wilkerson, PE
www.medeek.com