Roof Inversion! Eeeekk!

[TalkingTrees]

Evening,

Just a wee bit gusty over here. I had noticed a slight twist happening with my crown wheel and poles from previous winds, and realise now that this must have weakened the structure... After the 120km winds on the weekend, I came home to find the roof inverted and a nice funnel of water pouring through the middle. Luckily, it's pretty minimal damage (books, bed and clothes all dry!! yay!), no rips to damage to canvas or walls OR crown... but the galvanised nail that holds the 'nodes' (at the end of the poles that fit into the crown) have all been twisted either off or at a 60/90' degree angle..

I'm looking for ways to prevent this ever happening again? One pole came down and snapped over the bed - a nice lil dagger into the centre of a pillow - and although I love my yurt life and home beyond words, I do want to be able to live a long and happy life in there!

I am thinking of using stainless steel rods to connect the poles & nodes.. and extending the rod a lil extra further past the crown wheel so I can thread on an extra nut so it can't come out?

The walls are currently tied together with a strap - would wire hold more integrity/strength?

How do I fix a twisting roof/crown wheel if I notice this? Is that a normal 'settling in' of the poles?

Is it stronger with having the 2 support poles holding up the crown, or is it better to have the weight sitting on the walls?

Thank you! Xx

[Bob Rowlands]

Roof weight is loaded onto outside wall. However two or three poles under a larger 7 M yurt ring are absolutely essential to my way of thinking.

As for the connection of rafters to ring, I can only guess on that that since I am not an engineer. A single nail in the end of the rafter that pokes into a nail sized hole in the ring is very marginal imo. If there is enough cross section size in your rafters, you might keep with the same basic system by increasing the size to 5/16ths lag bolt that is maybe 6" long? Remove the existing nails. Drill a 1/4" pilot hole into the end of the rafter. Screw in the lag leaving two to three inches exposed, then cut off the lag head with a metal cut off wheel in your grinder. Drill corresponding holes into the ring. This is merely a guess. Never seen it or done it so take it for what its worth. Whatever you decide to do, build it with wind twist in mind. Good luck.

Off topic. The rafters on my little 16' yurt are 1x3s that insert several inches up into slots built into the ring. That is is a superb system for preventing twisting based inversion. I've been in my yurt in extreme high wind (70mph) and had no worry about inversion with that design. I lost one yurt in wind. Never again.

[yurtninja]

Having your roof twist is a bad thing, and will only get worse with time. The yurts we build have two pins in each rafter that insert into the ring, and we also use a screw in each rafter to secure it to the cable we thread through the top of the khana. I've witnessed roof rings twisting during the setup of yurts, and wouldn't want to be in one when it happened. I would take the opportunity while you have your roof off to take down all your rafters and reassemble the roof so that it's stable again and doesn't become a larger problem. Would you mind sending some pics of your rafters and how they connect to your ring and walls so we can have a better idea of how your yurt is constructed?

[froit]

If yours is a traditional yurt: you should have had the supports in. But even then. If the rafters are not at least 2 cm into the crown, it will sooner or later twist, since you are (I suppose???) tightening the outer ropes every now and then.
To stop the crown from turning, fix two ropes to one of the rings on the edge (do you have these???) and feed them over all rafters tangentially to the wall, or door. So with one of these you can then un-twist the crown, and with the other you can stop it from ever happening again. It's gonna be quite a pull, take your time. Alternatively, make two ropes to two rings on opposite sides, the ropes then meeting at the door. Also nice.
If you don't have a traditional yurt, only god may help you.