I posted this elsewhere but this looks like a more appropriate place to put it. I'm making box beams out of 1" boards. Various online how-to articles recommended deck screw sizes of 2 1/2 " to 3 1/2" to attach the preliminary board to the ceiling. The U-shaped beam will then attach to that board. I bought 3" deck screws and they have a one-inch shank so the screw doesn't actually bite into the board. It seems to me the only thing holding the beam to the ceiling will be the head of the screw. Is the screw too long? Are there other brands of deck screws with shorter shanks? Or are deck screws not the correct choice here? Thanks!

 

Need more info:
1" by what?
How long are these beams?
What is the ceiling you are attaching to re: gyp-rock/plaster and lathe etc.?
Are you going to attach the mounting plate to ceiling rafters?
Is the inside dimension between the U the same as the width of the mounting plate?
Are they painted or natural wood?

 

If it were my house I'd go with 1/4" x 3 1/2" lag bolts with washers every 4' or every other joist assuming that is what they are going into.

1" base + 1/2" drywall = 2" engagement into the joist!

I like to sleep at night!

 

1x6x9' and 1x6x12' beams, the ceiling is thin bead board covering, I suppose, sheet rock or whatever else is a common ceiling material and then into the joists. The inside dimension is the same as the mounting plate. Stained wood for the box, natural unfinished wood for the plate..

 

Thanks Mark, the lag bolts look more secure. The thought of that thing directly over my head at night has been giving me the jitters!

 

I would use a 2X6 as the mounting plate.
Get at least 2 inches of the screws/lags into the joists.
Predrill just to be sure that you are hitting the joists.
Also predrilling will minimize splitting of the joist if you are off to one side of it.

Then I would nail the box to this.
A power nailer would be ideal.
Try to angle the nails down a little.
If you can't you can't just be sure they do not angle up.
Do a stitch nail pattern.
One every 6 inches or so should do.
This will prevent the sides from splitting.

With a power nailer you may not even be able to see them so you may not have to do any filling.

 

Great ideas...thanks guys.
Martha

 

What is a "stitch nail pattern?" An internet search didn't help.

 

Your beams are only 9 & 12' long so there is minimal weight, the 1x material is more than sufficient.

After securing the base against the ceiling, you can nail or use 1 5/8 drywall screws (black) to attach the body of the box.

They will not be seen, one screw every 2' will do the job.

You may find that the ceilings are a bit wavy, a bead of caulk may be needed if gaps are present!

 

Just a zigzag with a nail at each peak

 

Thanks! Bead board, trim and base boards are up. So far, so good. I'll start working on the beams tomorrow. I bought Fin/trim trim head screws, 8 x 1 1/2". I thought they would be easier to hide than other screws, and I thought screws might grip better than nails. Will they be ok, do you think? I bought them earlier.