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I'm planning on building a home climbing wall in my garage. I'm wondering about the structural integrity of attaching it to the trusses. They are 2x4s, 24" apart, and span about 30 feet.

This image shows basically how I would build the wall (the left one): enter image description here

My wall will be 8' wide by 12' tall at a 45 degree angle (I have 9ft ceilings). Since this is a bit of an aggressive angle I'm concerned about attaching that much weight to my trusses.

I would also be adding some support from the middle/upper area of the climbing wall back to the garage wall, similar to this image: enter image description here

If that doesn't seem like it would be alright, how can I modify it to work? I was thinking I could add some 4x4 posts to the each side of the top plate, but I would prefer less intrusive options.

Would I need to reinforce the garage wall too? I can double up the studs if that's necessary

One last question, that original image is using 2x6s for the climbing wall frame, would 2x4s be alright as well? I've seen a bit of both on the internet.

Thanks for any advice.

Edit: Here are some pictures of the attic I took a while ago, I tried to add an outline for where the wall will go (roughly). enter image description here enter image description here

Here's an image to help visualize what I'm hoping the wall to be: enter image description here

EDIT: Current Plan

Per most recommendations I shouldn't attach much weight to the trusses. My current plan is to anchor the climbing wall heavily to the garage wall with joists at an angle (like the second picture but beefier).

For attaching the top of the climbing wall to the trusses I'm going to lay a 2x6 across about 6 trusses on top from within the attic and then bolt a 2x6 from within a garage to that one (so the trusses are sandwiched in between), that way I don't need to drill/bolt into the bottom chords at all.

I'll be doing the same thing about halfway between the top of the climbing wall and the garage wall and attach the climbing wall there as well. In that way whatever load is on the bottom chords will be spread out across a larger area.

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    45 degrees seem awful steep. How are the 2x4's supported? a 30' span needs something. Could you support the joists from the rafters? A picture of the garage ceiling would be nice. – JACK Mar 24 '20 at 18:09
  • Yes, did you actually mean 45 degrees? This would put half the load of the wall and its occupants on the roof system. – isherwood Mar 24 '20 at 18:38
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    Yes 45 degrees. Here are some pictures of the attic I took a while ago, I tried to add an outline for where the wall will go (roughly). imgur.com/a/N7TWDXR – Philll Mar 24 '20 at 18:40
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    Here's an image to help visualize what I'm hoping the wall to be: i.imgur.com/qUrX4iz.jpg – Philll Mar 24 '20 at 18:47
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    Please inline your images into the question rather than posting links. External links can go stale making this question useless to future visitors. – BMitch Mar 25 '20 at 12:00
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You need to define the type of garage ceiling you're looking to use. Not all trusses can be used for downward forces (say it keeps the walls from spreading) and if you're accidentally mis-describing them you could be getting some bad advice.

That said, assuming your climbing wall touches the ground the load will be carried there. Lateral forces on the side of the wall from 'pulling out' are supported by the cross bracing in ceiling. I'll see if I can find the article on design I read on the 'net about 3 years ago.

Edit: OK, going to give my non-civil-engineering view on this. https://www.menards.com/main/buying-guides/building-materials-buying-guides/roof-truss-buying-guide/c-19431.htm

The example image shows all of the load being pulled downwards (compression) to the floor, and the ones nearest the wall providing tension to pull the rest towards the wall. You should have a large piece of anchored plywood or 2x8 back there to bolt into- lag bolting into your 2x4 sticks in the garage. Then you can attach multiple points to the 2x8 and the 2x8 can resist twisting the rear wall.

The bottom chord of your attic is in tension- it's to hold the walls from spreading. The upper chords are in compression and are carrying the load to the double sill plate around the base. The remainder of the web is stiffeners and compression/tension. Diagonal'ed boards in the attic prevent your roof from twisting around.

Just really limit how much 'weight' the ceiling is holding. If you do the example you've got, really emphasizing connecting it to the wall, it should be fine. Assuming of course the wall is connected to the floor somehow...

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    I've updated the original post with some pictures. – Philll Mar 24 '20 at 19:12
  • Bad news: Those bottom chords CAN NOT take the load. – J.Hirsch Mar 24 '20 at 19:26
  • Do you have a recommendation for what I could do? Would adding the 4x4 posts I mentioned above work? – Philll Mar 24 '20 at 19:37
  • Per your edit, do you think I could attach it just to the wall? Similar to this board: i.imgur.com/NVT3k9t.png My only concern there is adding too much compression to the trusses – Philll Mar 25 '20 at 16:20
  • @Philll would you be okay if the angled supports went through the ceiling and on/upward to the second chord? Or if there were two vertical bearers, one on either side ? (might make it difficult to get a car in the garage.) – Criggie Mar 31 '20 at 1:12
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You have done an excellent job and this will be very strong (assuming a standard wall covering like dry wall or wood sheathing and not something odd like a heavy pseudo rock face).

Use #8 x 3" screws for the attachment to the underside of the trusses, (2) at each block and truss. No larger as this will compromise the truss too much, that member is in a state of tension. I suggest using the same screws everywhere, it's just easier than nails and you won't bang everything around. Get a powered driver tool of course.

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    seems you've got the PE and civil to better answer his question than mine- dunno what happened to all of the comments as they disappeared while I was typing. Looking at his photo of the attic the bottom members are dual spliced chords, and 2x4- I don't think they should take any additional weight over the 5/8ths drywall already on it. However the back wall (appears from the attic) to be fully supported, so should be able to resist any cantilevered weight off the wall. 250lbs @ 8' is pretty steep. Would you double lag-bolt to the wall to tie it together? – J.Hirsch Mar 24 '20 at 19:44
  • Re the trusses, they are designed for a dead load on the bottom cord, usually10 psf for things such as insulation and dry wall. The forces in the OPs design are more complex than simply downward force on the trusses, that is just one element. A lot will be taken up in the bending of the wall studs and other places. Wood has an amazing ability to redistribute loads. Wood is a lot stronger for shorter term loads. Wood has large safety factors. A lot of the vertical load will go directly into the wall anyway, as you suggest, even without the additional. More in next comment. – Ack Mar 24 '20 at 20:00
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    If the OP still has concerns, mitigate them by installing a 2x4 on the side of the truss from the point of attachment of the block to bottom cord up to the nearest connection point of truss brace members and top cord. The only issue of your concern is localized bending in the bottom cord and that is highest at the middle between the brace connection points. It is FINE as OP shows, however, I know that there is concern especially since I'm just some internet guy saying stuff (good to remember!) and this should be a way that is obvious to address the concern – Ack Mar 24 '20 at 20:10
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    You give no info about which joint connection or how far from the joint is acceptable. This is not acceptable. You made such a big deal that your a structural engineer to @isherwood yet you have overlooked some major issues: 1) double bending, 2) live load conditions, 3) weight of climbing wall material, 4) species and grade of truss members, 5) overload existing steel plate connectors, etc. that I doubt if your a licensed structural engineer. Structural engineers I know, qualify every item. They don’t just say, “it will be very strong” and then come back later and add web members. – Lee Sam Mar 24 '20 at 21:13
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    @Ack Btw, shooting from the hip is not ok for this site. Claiming to be a structural engineer gives a certain credibility and can severely impact the OP’s decision. (As you know, you’re held to a higher standard.) after all this, you never said “check with a structural engineer.” Instead you said “it’ll be very strong.” and you didn’t know or understand the loads involved for this rather unusual situation. – Lee Sam Mar 24 '20 at 23:54
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Your attic is totally capable of holding the walls and a climber's weight. However it cannot deal with a moving climber and I don't see how this would ever be legal (could void home owner's policy) without sign-off from engineer and city.

If you are going to do it no matter what then what you need to focus is cross lateral support in the attic. I would put some intensive blocking, I would add at least 2x4 stirrups across the top and would go with plywood over that but I might skip that due to weight.

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  • Wood can handle dynamic weight much better than static loads, it is one of it's unique properties. For impact loads, the design strength that we use is 2x that of consistent dead loads. Yes, that is correct, -double- – Ack Mar 26 '20 at 22:20

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