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Questions tagged [joists]

Horizontal support structures beneath the floor running between load bearing walls.

These may be solid wood, such as a 2x8, an engineered wood product, or a specially designed wood assembly with openings to allow the passage of utility lines through the joists (such as HVAC and plumbing) without damaging the structure.

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What are the guidelines for holes in joists?

I've been unable to find a good reference for the size/amount/location of holes I can drill through joists. This is mostly in order to pass cabling or pipes through the joist crosswise. Also, what about notching the bottom, is there a size…
Aaron
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Is it OK to drill vertically through a joist?

I just bought a new house and I'm looking to run some cables. One of the areas I would like to run it to would require drilling through a 2x10 sistered joist. Realizing that going through the joist should be a last resort, if the hole is 1/4" and in…
user13655
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How do I measure joist deflection?

I have a 3 story townhouse that was built in 2004. We recently redid the flooring in the top floor, and while we had the subfloor exposed we tried to eliminate the squeaking that we've been hearing by screwing the subfloor further into the joists.…
Zaralynda
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Should I add plywood or OSB between sistered beams?

I'm going to stiffen up my main floor joists by sistering then bridging them. In the past a friend put something in the middle, is that standard? Should I put 1/2" plywood or OSB in between?
RLZaleski
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How do I reinforce the ends of 2x8s that are sistered to 2"x5" (actual size) joists?

I want to strengthen the floor of my office. Currently the joists are 2"x5" (actual size). I want to put a 2"x8" (1.5"x7.5" actual size) which will double the existing joists. I will have to reduce the height of the new joists from 7.5" to 5" at the…
La Raison
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Are split joist hangers allowable in the USA?

I have a built beam in my ceiling that needs to be sistered. It was three 2x6s and will now be five 2x6s. One side will be supported by the top plate, but the other side won't. The final width of the built beam will be 8" actual width (it's an old…
Cthulhu63
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How to reinforce a floor joist with a split knot?

An electrician ran some new wires and had to bore through the floor joists. In doing so, one came very close to a knot in the wood. The floor above squeaks now as a result, where it didn't before. This is probably just a minor annoyance but I'd like…
Yuck
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Can a larger joist be trimmed and have it perform as a smaller joist?

I've got a lot of 7x2 joists left over from a previous project. Now I have a new ceiling to put up but they require only 5x2 joists, so I'm thinking of trimming the 7x2 so as not to have them go to waste. Would trimming a 7x2 to a 5x2 (or reducing…
JamesDean
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Joist hangers to use for rough cut 2x8 (2 3/4" x 8 3/4")?

I'm looking for the right size joist hangers for my project. I have an old house with rough cut oversized joists and can't seem to find a joist hangers that will work. I'm nailing into a 2x10 ledger. The joist actual dimensions are: 2 3/4" w x 8…
Hooplator15
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What is this metal plate in front of wooden joist for? Can I drill through?

I am trying to install a bike hoist on my garage ceiling, and ran into this piece of metal when drilling through the drywall to the joist: It looks like the material behind the metal plate is wood. Can you tell me what this steel is? Can I drill…
Winter Snow
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Do I need to brace joists after removing basement ceiling?

I'm about to take out the lath & plaster ceiling in the basement of my 1908 house (I'm hiring it out; I know how bad the mess is). Main reasons for doing this are to get access to wiring and allow me to insulate. This is in Iowa, not a seismic zone.…
skaiser
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How should I deal with lumber size differences when replacing floor joists?

I am in the process of replacing 4 floor joists and the new 2x10s are 1/4" taller than what was previously there. I understand that as the lumber dries out it will shrink but how do i handle the 1/4" difference to have a level subfloor and not crack…
Alex
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Mounting a Projector on a joist - Is Joint Integrity still ok?

I am mounting a projector on the ceiling in my single story extension with a sloped roof. My luck had it that there was a joist within range and I proceeded to drill into it from below through the plasterboard ceiling and fix the bracket as I…
user91821
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How can I level the joists and ceiling?

I am presently renovating a house that has a 4" difference from the middle to the one side due to the subsidence. It is a semi-detached duplex, with 3 floors including the basement. The worst is the basement and the 1st floor (4" difference). Now…
chaiyo
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How can I support a joist length of 9 meters without steel?

I want to convert my loft and need to span 9 meters unsupported. Can it be achieved without steel beams?
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