Complete Brain Cramp!

[John J. Passailaigue, Jr.]

Look at the ends of these floor joists and tell me if you think they are too far extended and could cause floor movement later. It measured 8 3/4" past the beam.

[Dale Duffy]

John,

It looks from the picture, both joist ends are sitting on the beam.

[Dale Duffy]

They might not end at the beam, but that doesn't matter.

[kmcmahon]

They shouldn't extend over the end of the beam further than the overall depth of the joist.....and it appears they do not.

[Dale Duffy]

Originally Posted by jpassailaigue

Look at the ends of these floor joists and tell me if you think they are too far extended and could cause floor movement later. It measured 8 3/4" past the beam.

R502.6.1 Floor systems.

Joists framing from opposite
sides over a bearing support shall lap a minimum of 3 inches
(76 mm) and shall be nailed together with a minimum three
10d face nails. A wood or metal splice with strength equal to
or greater than that provided by the nailed lap is permitted.

[John J. Passailaigue, Jr.]

Thanks fellas! Just didn't know if it was ok or not, that's why I came here to ask. Thanks again!

[Michael R. Boyett]

[Greg Veal]

John

My thoughts...

If the joists are lapped over the beam as suggested, length = or < than the depth of the joists and properly nailed, also as indicated, then the lifting/warping indicated in the graph shouldn't occur. If it does however, I'd be looking for other issues that may be causing this warpping issue. Issues could be 1) moisture, 2) substandard lumber for its use, 3) installation methods, etc.
I've seen this occur more in roofing (rafters) than in floors (joists). I also see more often when OSB is used rather than plywood.

[Robert J. OConnor]

The pic/diagram MB posted shows the potential result of excessive joist overlap, with the potential for a hump in the floor.

However IMO the 2" projection beyond the beam in the diagram is a little too restrictive, and the rule of thumb of an overlap no more than the joist depth KM posted is a little more reasonable in my opinion.

JMO & 2-nickels ...

[tdietrich1]

Just curious, after looking at my own house. If you follow the IRC's instructions to tie both sets of overlapping joists together with nails, floor bump risk should be eliminated right?

Not asking for guaranteed options, just educated ones.

thx,

tom <== has bouncy floor, tested by 4 year old hyper boy.

[Robert J. OConnor]

The IRC only calls out a handful of nails at the joist overlap ... unless it's the top floor ceiling joists with a lower roof slope and significant snow loading where more nailing is required. But even then, you would need a lot more than that at each overhang to restrain the ends from having a tendency to move upwards.

JMO & 2-nickels ...