6

I installed a projector and a screen a few days using toggle bolts in my drywall ceiling. One of the anchors didn't open all the way up, and the screen fell. So, I searched here, and quickly came to a realization that hanging anything heavy from the drywall ceiling is a terrible idea. I took everything down, and would like to mount the projector directly to the joists.

Here's what I have in mind. a sketch of mounting the projector the to the ceiling

  1. What kind of screw should I be using to secure the extra wood to the joist?
  2. How far into the joist should it be going?
  3. Does it matter what I use for the extra wood (pine or MDF)?
  4. What kind of screws should I use to secure the projector to the extra wood? I can't really use bolts, since the extra wood will be flush with the ceiling.
  • you could counter sink bolts between the wood and projector – Jon Nov 2 '17 at 14:48
  • I mean bolts with nuts, but I guess lag bolts would work. Would it be better than using screws? Does it matter if the lag bolt for the projector end up piercing the drywall and just be sticking out from the other end? – PBG Nov 2 '17 at 14:49
  • As long as the lag bolt has threading along it's whole length, it would be fine structurally – Jon Nov 2 '17 at 14:51
  • @isherwood, there are internal screws, there are lag bolts, and the hardware section at home depot is overwhelming. I figured there's a preferred way to attach stuff to joists, which is why I am asking. – PBG Nov 2 '17 at 14:52
  • 1
    1) Do you just happen to have easy access to the space between the joists from above? If so, you could mount a cross-member between the joists and avoid the "extra wood" part being visible. 2) If there happens to be a joist wide enough where you want to mount the projector, two decent-sized woodscrews will easily be enough to hold its weight. IMO. – Andrew Morton Nov 2 '17 at 20:01
5

I'm assuming your projector isn't terribly heavy, so...

2 1/2" gold construction screws should work fine to hold the board to the joists. I also like to use decking screws because of their strength and color. They both have small enough heads that shouldn't stick out once they are tightened. I think that larger fasteners like lag bolts just aren't warranted for this project.

The 2 1/2" screws should end up going into the joist about 1 1/4". If you use a thicker board for support, you might want to bump up to 3" screws. Try to get more than an 1" into the joist.

Since this is interior, and not a large span to tremendous weight, pine or MDF should be fine. MDF will be easier to work with because it will not be warped or twisted. I used it to mount my TV to the wall.

Any wood screw that goes into the full thickness of the mounting board should be fine to hold up the projector mount. Even if the screws are a little long, they will just poke into the drywall a bit, which will be fine. Use a screw as thick as possible based on the holes in the mount, and use as many screws as you have holes for.

  • 6
    I recommend gold construction screws over drywall screws. Black oxide screws are hard and brittle and not as suitable. – isherwood Nov 2 '17 at 14:57
  • 1
    I'll agree to that. I usually have drywall screws handy, and they are holding up the drywall, but construction screws are nicer. – JPhi1618 Nov 2 '17 at 14:58
  • 2
    @JPhi1618 -- you might edit your answer to exclude drywall screws if you accept that they are brittle and at risk of breaking in this application. (Part of why they work so well for drywall is that they are sharing a load among many fasteners.) – Aloysius Defenestrate Nov 2 '17 at 18:18
2

I'll attempt to answer with an incomplete understanding of the problem. The bottom line is that screw size is key, not type. After that, choose what looks best for your use case.

  • The screws that mount the board to the ceiling should penetrate the framing at least 1". They can be anything from a #8 construction screw on up.
  • The screws mounting the projector to the board should penetrate 1" or the thickness of the board, whichever is less.
  • Any screws larger than #10 or not self-piloting should be piloted slightly smaller than the shaft diameter.
  • The type of wood is not critical. Pine or MDF are fine, assuming an adequately large piece (a 1x2" strip is probably not appropriate).
  • 2
    I actually might grab a piece of hardwood for this. Nice and straight and holds screws well and who cares if its $2 or $4.. – agentp Nov 2 '17 at 15:07
  • 1
    A quick stain to coordinate with your woodwork is easy. Wouldn't even need to varnish it, really. – isherwood Nov 2 '17 at 15:08
2

For most projectors (not that heavy these days), you can (depending where it needs to end up relative to the joists) put a single piece of wood that's wide enough for the projector mount screws and screwed into one joist. If it needs to be between joists, the method you show is better, unless you are doing drywall work anyway (or have access above, as when it's an open attic, not the next floor), in which case you cut a hole (or not if it's an attic) and put that chunk of wood between the joists above the drywall, then patch it (or not if it's an attic.)

For screens, in most cases you are better off putting hooks directly into the joists and hanging the screen on chains, which allows the end of the screen to not line up with the position of the joists, yet still be solidly connected to them.

If you want a "bolted" connection, drill holes and install "T-Nuts" into the board before screwing the board to the joist. Or, drill a shallow countersink and a hole and install carriage bolts from the top before screwing the board into the joists. The first way you'd have machine screws/bolts, the second way you use nuts/washers to finish the mount attachment. The prongs of the T-nut or square part of the carriage bolt are to keep each from turning as you connect the other side.

T-Nut enter image description here

  • 1
    If you want bolted construction, use unistrut :) sheet of luaun plywood as a hider and yer done. – Harper Nov 3 '17 at 2:24

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.