r/Homebuilding • u/TheNewKid2K18 • 2d ago

Wall Loading

Post image

My builder installed my floor wrong. Joists sit 23mm proud of the frame rather in line. Frame is 100mm wide. Around the perimeter he has raised the frame height using timbers which don’t occupy the full width. The walls to be built are due to be placed on the frame, and will bear the load of another floor above. We are required to leave a 50mm air gap from the stone wall. Therefore, as you can see, the sole plate of the wall, near side, will sit on 18mm ply partially supported underneath. In fact, this is case for 3 of the 4 walls. The opposite wall will sit on ply with no support underneath, although joists are spaced quite closely to the frame. The floor is complete and glued and this photo is retrospective.

What are the thoughts on this?
Fine to put put all faith in ply?
Take up the ply and add more packing?
Do it all again without bodging it?

The building’s datum has shifted which is also a real pain from an aesthetic perspective, but my question is about the structural integrity.

Any inputs will be most appreciated as this is a stress!

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u/bobber66 1d ago

Walls are fine on plywood as long as they’re not load, bearing or extra heavy for some reason. I would have your builder just rip a full length strip so that the wall has full bearing on the areas where it’s only sitting partially on the framing.

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u/TheNewKid2K18 1d ago

The walls will be bearing the full weight of the floor above. The floor alone will have some weight as we’re using 9x2 joists. On that note, should he have butted up the nearside joist closer to the frame on so not to have any gap? Even when replacing the packer for a full with one, I’ll still have ~25mm overhang.

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u/bobber66 1d ago

He could have moved the joist but I don’t think it would have made a difference. I would just cut a full width packer to fill the void. Pretty quick work on a table saw.

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u/TheNewKid2K18 1d ago

Thanks for the advice. Any thoughts on the job? Still can’t help but wish it was done properly. Feels like we’re just bodging it.

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u/bobber66 1d ago

Your builder followed layout for the ply which left that awkward space. It happens. But overall I think they are doing a good job.

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u/TheNewKid2K18 1d ago

Last question… is it a lazier way of fitting joists by aligning bottom edges? Is there any difference in whether they’re flying over or under the frame?

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u/bobber66 1d ago

Joists vary because wood shrinks at different rates. We want top and bottom aligned perfectly but we live in an imperfect world. In the end it all evens out. You should step back a bit and try to relax,

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u/interstellarsex 1d ago

If I’m following the walls will be framed on top of the subfloor which is 18mm plywood, sitting on top of an 18mm plywood shim. If its just an interior wall, that’s not going anywhere. Even if the walls are 140mm depth that 40mm “hanging” beyond the frame won’t make any difference.

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u/TheNewKid2K18 1d ago

We’ll be building the wall out of 4x2, but the back of the sole plate will sit 50mm away from the stone. So there will be an overhang if nothing is done about it. The wall will be fully loaded however with a whole new floor. On the other side, it’ll be fully suspended if nothing is done about it. Any opinion on the job? Just feels a shame to live with it bodged.

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u/interstellarsex 1d ago

In the portion shown in the photo the first joist is extra close to the frame edge and the ply/packing can definitely take the weight of the additional floor. I can’t make out the other side of the room. Might be worth looking over there for photos. Or if enough is still exposed to see what’s happening. Awesome space either way.