As the winter is coming, we're planning with my wife to build a simple, indoor climbing frame for our small children and ourselves.

We're also thinking of doing it ourselves as we can't afford to pay a lot for someone to do it for us. I'm not a wood working pro by any means, but I have and am reasonably comfortable with jigsaw, drill, sander, etc.

We've been doing some research and thinking, and I think we have a reasonable design which should be 1) easy to build, 2) low cost, 3) stable enough.

As context, our house is a timber frame building where all internal walls and ceilings are made of plasterboard, so anchoring is out of question, but we do plan to at least secure the frame to the walls.

Without further ado, here are our current sketches:

Photo sketch

Hand drawn sketch with sizes

So the idea is to have 4 vertical poles in the 4 corners and 4 support beams in a rectangular shape on the top. The rope ladder and climbing net will be suspended from the top beams.

Since I don't think I'd be able to do some proper wood joints, I was searching around and found some three way metal connectors:

Three way metal connector

From: http://www.allsteelshedframes.com/steeltimberconnectors.htm

So the idea with these is that the beams would slot in, but the whole frame would be height adjustable as the pole bit has holes on both ends.

My first question would be, how are these called? I only found this US based site, but I'd like to buy them in the UK.

As for the timber, I was thinking of getting 75mm*75mm poles in 2.4m length, like these for example: http://www.ebay.co.uk/itm/3-x-3-75mm-Pressure-Treated-Timber-Wooden-Gate-Fence-Post-1-8m-2-4m-6ft-8ft-/151978589963?var=&hash=item2362a13f0b:m:mT27JK_Z9k8n_Z_wD0EmnTg

So the second questions is, would this construction be solid enough to hold a light adult (I'm ~70kg)?

Thanks in advance for any comments / help!

  • I was reading down and wanted to suggest you over-engineer the heck out of it for peace of mind but I see you've already done so :-)
    – Graphus
    Oct 25, 2017 at 16:35
  • 1
    You'll want to avoid the pressure treated wood probably - you won't need (or want it) inside your house Oct 31, 2017 at 0:54
  • Thank you so much @DaveSmylie, I had no idea that the innocent sounding "pressure treated" actually means oozing with strong chemicals!
    – dain
    Nov 14, 2017 at 15:11

1 Answer 1


I have no idea what those connectors are called. Your local metal fabricator will be able to knock some up though. I suspect a cheaper approach would be to bolt the horizontal beams to the vertical columns (but that won't work if this needs to be dismountable).

Your timber frame house will have timbers in the walls that you can anchor things to (although they may not be that big timbers).

My immediate reaction on seeing the sketch is that there is no shear strength. The top will slip sideways until it bangs on the wall. A couple of diagonal braces will make it much more stable.

The columns will probably be OK in 75mm (although I notice the link for the connectors is for 100mm timbers). The columns won't buckle at that sort of length, but the beams are going to be awfully bouncy. The sagulator says that a 75mm square beam of Douglas Fir with a 70kg point load in the middle of a 2m span will sag about an inch. That is an underestimate because: a) 75mm timber is actually thinner than 75mm; b) the span is wider than 2m; c) that is a dead load, and you need to allow for you bouncing a bit (and your children bouncing a lot).

Personally, I would want to go for something like 50mm x 150mm which will give you much better stability - and if it's actually 3m, you are going to need a really chunky bit of timber.

Go and have a look at a climbing frame on your local children's playground. That will give you an idea of the sort of size timber you need for stability.

My final thought: does your room have enough head height above the frame?

  • excellent points all around!
    – FreeMan
    Oct 30, 2017 at 18:50
  • Thank you so much for the thorough post! I have just a few more questions based on what you wrote: 1. How would I use 50mm x 150mm timber, the 50mm side down for the longer beams and the 150mm side down for the shorter beams? 2. What would be good types of wood for this? I'm guessing something more rigid for less sag? 3. Would it be enough to add short diagonal braces only under the long beam? I'd have 60cm leftover pieces from the short beams if I get 3m long timbers As for your question about the height, I'll probably need to replace the lampshade with a flat, ceiling mounted one.
    – dain
    Nov 3, 2017 at 14:34
  • You are (mostly) worried about movement in the vertical plane, so you want 150mm vertical for both long and short. (If you were really trying to optimize this, you might be able to get away with slightly less for the shorter beams, but I wouldn't bother.) Nov 3, 2017 at 14:36
  • The stiffer the wood, the less of it you need. On the other hand, it might be better to use a larger piece of cheaper, less stiff, wood. The Sagulator (linked in my answer) has a lot of different woods to choose from, but it's very US-centric. Getting the expected stiffness of the wood you are buying from your local timber merchant may be hard. Nov 3, 2017 at 14:43
  • 600mm braces would certainly be a lot better than nothing. Again: have a look at children's climbing frames. Nov 3, 2017 at 14:44

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