# 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. Commented May 23, 2020 at 17:44
• I'm not sure how to add a diagram ? Commented 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? Commented 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.) Commented 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. Commented May 23, 2020 at 20:08

Deck screws are unsuitable for that use. They are light in gauge and usually have a bugle style head. You spaced them very close together so you are 'getting away with it' for now.

Most installations don't have a lot of direct pull out pressure, it's often mostly a shear load. Your installation is almost wholly in the pull out category.

In this situation I'd want a screw with flat bottomed head of a decent gauge (10 or 12 at least) and maybe even a washer to further resist pull out. You can increase the spacing but you'd still want at least 8 big screws. You can use a flat spade bit to drill small sockets or recesses to hide the screw head and washer.

There are various deck building framing screws which would be suitable, choose ones with large heads and thick gauges.

• Deck screws have some pretty impressive performance. I wouldn't say unsuitable. youtu.be/kAxGAIFbqu4 though I do agree pan head + washers would be better Commented Dec 31, 2020 at 6:44
• @whatsisname A screw designed for holding down one inch or so of decking under minimal load, does not (in my professional opinion) make it suitable to hold a 2 by 4 climbing frame to a ceiling along with the weight of a person... Commented Jan 1, 2021 at 10:08

Screws that professional climbing gyms use:

I am not climbing wall builder, I thought your post was interesting and so I did some deep google searches ;-)

• This feels very spammy. If it's not, please edit to indicate your connection with the screw vendor. Commented Oct 20, 2022 at 11:12
• I have no connection with the vendor. Not spam either, not sure why a vendor would head hunt on here just to hustle their screws. Commented Oct 20, 2022 at 13:31
• Stick around and be prepared to be amazed... We get all kinds of spam. When listing a specific vendor's product it's best to edit your question or answer to indicate that "this is an example", or otherwise point out your affiliation (or lack thereof) with said vendor. Otherwise, things get deleted on the presumption of spam posting. Commented Oct 20, 2022 at 13:36
• I will do that from now on appreciate the heads up Commented Oct 20, 2022 at 13:54

10 screws are never gonna pull out unless his kid weighs 300 lbs and swings on it. However washers aren't a bad idea in any plywood meant to hold weight against the screw head.

• Welcome to Home Improvement. If you'll take the tour and have a look through the help center, you'll note that this is a Question & Answer board, not a general discussion forum. As such, we expect something a bit more concrete than "y'all are going overkill". If you have some references to point to as to the strength of your "10 screws" and their pull out resistance, that would help immensely. Commented Oct 20, 2022 at 11:14
• It will be the combined effects of shock loads - also the screws won't be loaded evenly... Commented Oct 21, 2022 at 12:43