Bending lattice wood

[Andy_in_Germany]

I know that in a Mongolian Yurt the normal approach is to steam bend the poles for the lattice, but do I need to do this on a yurt with vertical rafter supports going down to floor level?

[Bob Rowlands]

I'll make a >guess< and say that American yurt companies do not bend their lath walls. For one, it raises costs and it is a competitive business. Secondly, the American style yurts I see have the wall set in a diamond pattern, not a square pattern like Mongolian yurt. Diamond pattern keeps the laths more vertical, so they twist less as they follow the wall curvature. Vertical, no twist. Diamond, moderate twist. Square, maximum twist. Just a guess though. Good luck.

[Andy_in_Germany]

One of those "Why didn't I notice that"? moments.

That means shortening the lattice rods of course and the spacing will change.

I suppose there isn't some handy conversion table or set of measurements that I can't find on Google, is there? No?

Looks like a large scale drawing of a lattice will be required then.

[Bob Rowlands]

I know of no yurt 'wall height and spacing' calculator. lol Carpenters like me just wing it and lay this stuff out empirically. So yes, layout is absolutely the way to go. I do that all the time.

My laths are 90" long. The wall height is 62" to rafter bottom. Mine is is a Mongolian style rustic yurt. I made the door. The door is low ya gotta bend over a bit to enter and exit. The wall has squares not diamonds, and the laths are at a 45 degree angle relative to the deck. The laths are not steam bent so there is definitely a noticeable bow inwards. The lath crosses are on wide 12" centers, not the close spacing of real Mongolia yurts. Their yurts are hell for stout, with a very tight lath spacing and one rafter per cross. Their walls are about 4' tall which means there is less volume to heat in the winter. Plus they are short people so door height is no issue.

8' laths can yield a wall that is much taller than 62", but they'll be in a diamond pattern. You'd have to custom build your door. No problem with that just sayin'. If you wanna mess around with shorter wall, but somewhat taller than mine, preliminary to actual drawn layout, get two 2x4s 8' long. Drill a hole 3" in from the end in each, and lash them together with cord or a bolt. Splay them out and see watcha like for height.

Getting into bigger non camping type yurts with increased wall height, and for reference and consideration, a standard American door height is 6'8", or 80". Normally that goes in an opening 83" tall. A 2x4 framed yurt door jamb with header set flat, not vertical, means the wall height needs to be 84.5". Frankly imo fitting a standard American door in a low yurt wall is goofy. I'd go with a wall that is 8', standard height and that requires laths cut from 10' studs, minimum, if on a diamond pattern. A 45 degree angle would require 12' studs.

There you go have.

[Bob Rowlands]

..fun. lol

[hierony]

The SimplyDifferently website actually has some nice calculators where you can adjust most of the parameters you're looking at.

[Andy_in_Germany]

That looks incredibly useful for a non-mathematician. Many thanks.

[Bob Rowlands]

Andy, there is a current thead on this forum entitled: Different types of yurt

insulation

There are a couple photos on there of a yurt with diamond shape in the lattice. You can plainly see that running the lattice in a more vertical orientation helps alleviate that hyperbolid shape where the lattice bows inward.