Hey,
I’m currently building an indoor climbing wall in my basement and I’d like to include holds on the ceiling. The ceiling consists of Silent Floor engineered i-joists like these:
Ideally, what I’d like to do is attach a sheet of plywood to the ceiling, either directly to the i-joists or attach strapping and then attach the plywood to the strapping. There may be a dynamic bodyweight load pulling down from these holds depending on how I set the route. Are these i-joists strong enough to hold that kind of a load from below?
What’s the best way to attach the plywood to these?
Replies
Seems like the manufacturer would have the definitive answer, but I'd be comfortable stapling the begeebers out of plywood attached directly to the bottom of I-joists. We use them for rafters and I think the wind creates pretty significant uplift force as it passes across the roof plane, doesn't it?
I don't see how much you could gain by blocking between joists, or strapping beneath them. If they're gonna pull apart, seems like you're still relying on the glue adhering the bottom flange to the web, aren't you?
jb
It actually looks like the previous owners of the house already put up blocking. Would that render the strapping redundent?
Yes, I would be relying on that glue holding the flange to the webbing. It looks like the manufactuing documents say that it's rated for 500lbs per 5', but that's more of a static load (ala water pipes). I think climbing on a holds attached to the bottom would be more of a dynamic load--especially if there's a difficult move that you need to jump to. I'm not sure how high of a load that would get up to.
Jump up and grab hold of one of the joists by gripping the bottom flange. Bounce up and down as if you were climbing. I will bet real money that you cannot break the joist when doing this. If I'm right then go ahead and screw plywood to your hearts content. Attach your climbing nubbies anywhere. If I'm wrong, you'll have to fix that one joist.
I'm not sure what exactly you mean by "dynamic bodyweight load".
I'm guessing you're talking about doing pull-ups on something? Or fastening some kind of kinky hanging chair?
My first thought is that you' be more likely to pull screws out of the bottom flange than damage the I-joist.
If you're in doubt, I have 2 suggestions. One is to bolt some kind of bracket to the OSB web, and support your load from there.
The other is to spread the load out over a couple of feet, and at least 2 of the I-joists.
If you are really concerned about the bottom pulling off then attach (glue and screw/finish nail/staple) 1/2 plywood to the sides on the chords thus joining the top and bottom chords together. Now you have mini box beams and it should also have the added benefit of stiffening the whole assembly making your floor less bouncy. Its probably way way overkill but it shouldn't budge.
Hi there,
I know this is two years after your initial post, but I'm also trying to build the ceiling part of a climbing wall, secured to similar engineered joists. I was hoping you might describe the solution you used in the end, and how it worked out for you.
Many thanks! And happy new year
glued and screwed blocking is best
You want to transfer concentrated loads to as large an I-Joist area as you can. If you can transfer it to other I-joists that's cool. Block out both sides of the I-Joist with 2x material; GLUED and screwed. Use a clamp to hold things in place while you srew. Your screws should be long enough to penetrate the opposing 2x and then some. Now drill a weight-bearing hole in the upper third of the beefed-up I-joist. Run a piece of pipe through it if you will. Run your mechanical fastener through the pipe/hole (on both sides and down to the bottom of the I-joist.
Another method of spreading concentrated weight is to bolt a beam (2x material) that, in turn, is bolted to the beefed up area of the I-jost, as described above.
Two things to keep in mind: 1) spread the load and 2) make sure your attachments are strong enough to hold at least 2X the expected weight. And...um...if anything gives and you break your neck, don't fault the I-Joist manufacturer! :)
Thanks for the feedback, it's certainly appreciated. I've done a lot of reading on these various methods but most seem to assume that a concentrated point load is being created
In my case I have about a 10' by 10' area of my basement ceiling with engineered joists running every 20" or so between the foundation wall and a steel I-beam. All in all I have about 6 joists to work with, and so my plan was to run three 2x8s perpendicular to the joists to cover the 10" span, which would give me ample surface to screw my 3/4 plywood to, which would allow for mounting climbing holds on the ceiling. I was planning to use 5/16 x 4" structural screws to secure the 2x8s to the underside of the joists, drilling 5/32" lead holes, with two screws centred on the joists at each point where the 2x8s crossed a joist.
I feel this is plenty strong enough to prevent anything from falling, even with dynamic load, and distributed enough to prevent a concentrated point load. My concern is whether using this many structural screws directly into the bottom of each joist would weaken the joists themselves. I plan to call the manufacturer this week, but saw this post and was hoping to get some feedback from someone else doing a similar thing.
Hang your plywood using a little common sense. Use deck screws, not drywall screws. Space them a foot apart or so and make sure they penetrate an inch or so. You couldn't pull the plywood off witha truck after that.
You will not get the answer you desire
You can call the manufacturer if you want, but I (and I suppose many others here) can virtually guarantee the answer won't satisfy you. Why? Because I-joists were not manufactured for your partiuclar application. Their purpose is to BEAR (as in, "shoulder) loads. The integrity of each I-Joist is dependent on the interaction of its components. Your proposed design isolates one component. I'll bet my sweet bippy (whatever that means...sigh) that there is no test data relative to your partiuclar application.
You are dealing with a "gray area" in design and construction. Your safety is at issue. Therefore, spread the load as much as you are able, and beef up the I-joists in ways described earlier. An ounce of prevention.... (you know the rest).
But it's quite common for a ceiling, possibly including "mechanicals" such as plumbing and HVAC ducts, to be hung from I-joists, so there is almost certainly SOME rating for this scenario.