UKC

Hello,

As a result of climbing gyms being banned, I have decided to build my own one in my attic. I have already bought 18mm hardwood plywood as well as a bunch of wood screws for holds.

However, I am having a bit of trouble buying the bolts I need.

I have bought these holds:

• https://www.euroholds.com/en/l-holds/575-9l.html
• https://www.euroholds.com/en/m-holds/243-19m.html
• https://www.euroholds.com/en/xxs-footholds/759-50-xxs-holds.html

And I intend on buying these and maybe some others:

• https://entre-prises.co.uk/product/climb-it-free-radicals/
• https://rockrun.com/collections/climbing-holds/products/bleaustone-training...
• https://www.hardwoodholds.co.uk/store/p130/Incut_Crimps.html

Euroholds is good because it tells me I need 40mm caphead bolts. However, I cannot work out which types of bolts to buy for the others two, only their length.

Any advice on how to find out?

Thanks.

Countersunk m10 of whatever length the hold requires.

https://imgur.com/a/09rKwjO

Flat head.

https://www.climbingwallservices.com/shop/climbing-hold-bolt/m10-50mm-count...

How do you know?

6 years of route setting and managing a climbing wall, I've used both those hold sets and know they take flat head m10 countersunk bolts. The wooden ones need 5mm screws, KTX are good if you're going to be moving them around a lot. 

Thanks!

Would you be able to help with something else please? I am trying to work out which screws I will need to connect the plywood to the studs in my attic.

I go into more detail here https://www.reddit.com/r/DIY/comments/fmp1nq/attic_climbing_wall_to_survive...

Ok, so what you have is a length of timber running across the top of the joists, directly below the purlin ( the 18cm section). You can use right angle brackets to fix 4x2 uprights (studs not slats) to the length of timber. 30mm screws would be fine for those. Fixing the ply to uprights use 50mm - 60mm 5mm screws. 

So what you're suggesting is this https://imgur.com/a/AEYrs85?

Where the black lines are 4x2 studs that are attached to the horizontal wood that I have scribbled in blue using right angle brackets (presumably behind the studs?)? If so, how would you suggest I connect the black pieces to the yellow scribbled piece?

Additionally, do you think it is necessary for me to place some horizontal 4x2s as shown in red?

Thanks for your help with the screws. Should I use 50-60mm screws to fix the plywood to the existing slats?

The upright black sections in your diagram can be attached with an angle bracket as described by flour above. 

I haven't quite got a grasp on what shape your trying to build, but if your screwing directly to the rafters I would have thought its going to be strong enough as it is without needing the 'red' part of the diagram. The ply you're attaching here will do a similar job and if it's attached to each rafter to stop it bowing out under the force of pulling on a hold. 

I have tried to represent my understanding of it here https://imgur.com/a/F7huC3m

In both images we are taking a side view.

In the first image, the orange line is the wood going along the floor. The black line is the 4x2 stud. The blue square is the scribbled blue wood from the previous image. The purple lines are two right angle brackets and the yellow lines are screws

In the second image, it is the 4x2 stud at the top end, hence the yellow rectangle is the scribbled yellow piece of wood from the previous image.

Is my assumption shown in the first image correct?

How would you join the two pieces of wood in the second image?

Just screw through the black studs into the blue marked wood. Angle bracket on the floor might not even be necessary but it could help stop excess movement when your climbing so probably a good idea. 

Cut the top of the black studs at an appropriate angle so it fits nearly under the purlin and screw through.  

I see, thank you.

I'm getting a lot of concerns about possibly tearing my roof down or falling through the ceiling on Reddit (https://www.reddit.com/r/DIY/comments/fmp1nq/attic_climbing_wall_to_survive...), so may need to reconsider unfortunately.

Yes use the 50 or 60mm screws to attach to the existing rafters (slats).

I agree with all of Luca's answers.

I think the roof should be ok as the rafters and construction should have been designed to take account of the extra loading of snow. However I'm not a structural engineer. It would make sense to have a tie beam connecting the rafters of the two sides of the roof to take some of the extra load. Quite how you beef up the floor to avoid damage to the ceiling I am not sure. 

I have started drilling the holes for the tnuts but I have a slight concern. The tnut does not reach all the way through the wood. Is that a problem? Will the bolts still fit?

Pictured here https://imgur.com/a/kHKMZlH

I am using these tnuts https://coreclimbing.co.uk/buy-fixings/fixings/m10-t-nuts/pronged-t-nuts-10... and the plywood is 18mm thick.

Its fine, they don't.