Questions around designing and building an indoor climbing frame

Question

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:

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:

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!

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?