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I have some beams in my ceiling that have been sistered with some steel plates. The long term plan is to put drywall as a finish, but that would require screwing the drywall to something. You can't screw drywall to a 1/2 inch steel plate with bolts / nuts in it, so I was thinking of attaching furring strips on top of the steel to screw the drywall into.

This leads to the question of how to attach the furring strip to the 1/2 steel plate. I have seen references to gluing wood to steel, and my question is if I can find a glue that is rated for both steel and wood can I just glue a furring strip onto the steel, and then screw the drywall into the furring strip? Is there anything I need to be cognizant of, like expansion / contraction of the wood?

beam

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  • do you have a picture? do you beams look like that? terrylove.com/forums/index.php?attachments/… Jan 31, 2022 at 18:51
  • See new picture. The steel plates are on the outside, as opposed to on the inside between the wood.
    – zelinka
    Jan 31, 2022 at 18:54
  • I appreciate the quick accept! You may want to hold off on that a bit to encourage others to chime in too, just in case those with more experience than I indicate that this is a severe no-no.
    – FreeMan
    Jan 31, 2022 at 19:10
  • The exposed steel is an interesting design element. Why would you want to cover it up? Feb 1, 2022 at 1:45

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Having just spent a couple of minutes perusing the "construction adhesive" section of my favorite big box's website, it appears that polyurethane based adhesives will adhere to both wood and metal. There may be other types that will adhere wood to steel as well. I'd suggest taking a look at what your local store offers then check the manufacturer's web sites to ensure that the product(s) you're looking at are recommended for both materials.

It's good you're thinking about wood expansion, but the amount of expansion will be minimal on a 1x2" or 1x3" furring strip. Wood will expand across the grain (in the x2 or x3" dimension, and somewhat in the 1"x dimension), but almost none at all along the grain (in the 8' dimension). For your reasonably stable indoor environment (heated and air conditioned, I presume), there will really be no expansion/contraction to worry about on wood this small.

The only potential issue I see is having sections of drywall over head screwed into something as thin as a 1x furring strip. If you use 1/2" drywall, you'd have to use a max of a 1-1/4" drywall screw (1/2" drywall plus 3/4" furring strip) or your screws will hit the steel and spin (stripping out the hole in the wood and drywall), and won't hold any more. This will give you only 3/4" of screw holding up the drywall.

If you go to 3/8" or even 1/4" drywall, you'd need even shorter screws, but each one will carry less weight and have more of the screw embedded into the wood for a better hold. You could also double the thickness of furring strip to give you more wood for the screws to hold on to.

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