# How much weight can a 3.5" deck screw hold before pulling out?

I have built a climbing wall in my daughter's bedroom room. There is a portion on the structure that is completely horizontal on the ceiling, it is 36" × 36". The framing consists of 2x4's. I fastened them onto the sheetrock with 3.5" decks screws. The deck screws go into the 1.5" stud through the 0.5" sheetrock and penatrate the ceilng joist 1.5" I used a 3.5" screw every 4". How much weight can the screws hold before pulling out?

• Hello, and welcome to Home Improvement. It's going to be hard to say without a diagram, but it sounds like you're being cautious, which is good. And, you should probably take our tour so you'll know you'll know the details of contributing here. May 23, 2020 at 17:44
• I'm not sure how to add a diagram ? May 23, 2020 at 17:58
• Thank you and yes from that calculator it say 164lbs. Would you think that means if you have multiple screws it increases the total capacity? May 23, 2020 at 18:10
• If you got 164# pullout from one screw (not surprising to me, btw), then you'll get ~10x that from 10 screws (and so on). The only quirk is the possibility that you hit the edge of a joist, which will reduce strength. I'm assuming you used 3/4" ply for the mounting surface? (That's standard in climbing gyms, so I'd have to assume it's up to the task.) May 23, 2020 at 18:41
• I don't believe deck screws have a specified use or ultimate yield value. I suggest you replace the deck screws with a structural screw, like something from GRK, Simpson, or other manufactures. I have some 5/16"x4"GRK structural screws on my shelf, that states an ultimate load of 1,196 lbf. Note that the wood is probably going to yield before these screws do. May 23, 2020 at 20:08