In my attic there is a beam that ends 80% of the way through. A few of the joists are connected with nails but are unsupported laterally. Should these joists have better support?

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    What is below? That looks like a wall that the beam and joists are resting on. If there’s no wall there, then I’m surprised the ceiling hasn’t fallen yet. Nov 15, 2020 at 16:59
  • "Should these joists have better support?" Probably not, if they are used for supporting the ceiling. If you intend to use them as attic floor joists then you are using them in a way that the structure was not designed for and nobody can answer the question without having a good look at the overall framing layoutof the entire area. Nov 15, 2020 at 17:16
  • Is it safe to put plywood over this area to provide easier maintenance access to the furnace? Nov 15, 2020 at 17:23
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    Given that it's a tiny amount of additional work, I'd add blocking between the joists where they lap. Nov 16, 2020 at 2:35

1 Answer 1


In my mind, it comes down to what's under that beam and ceiling joists. There should be a wall under the joists (looks like that may be the case 'cause you can see what looks to be the top plate of the wall under the joists), and a built up post of some sort under the edge of the beam.

If those conditions are met, than you should be OK to put down the plywood over the joists.

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    Your answer is good but if, for some crazy reason, there wasn't a structure below those two joist connections then adding plywood would be better than not, because the ply would span and sister multiple joists.
    – Matthew
    Nov 16, 2020 at 2:34
  • Potentially yes, @Matthew, however, horizontal spaces tend to collect more than just dust, which could be dangerous. If it were my ceiling and I were to add plywood for strength, I'd build a 2x4 pyramid above it to discourage placing things (like people) there, and attach a sign to indicate it's not to be load bearing. But, then, I also don't like things going through ceilings...
    – FreeMan
    Nov 16, 2020 at 19:07

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