Advice on a method for building our platform into a circle

[Nicholas Russell]

Hi All,

We are in Southern Ontario and I've been hard at work preparing for our yurt to arrive from

Yurtz by Design

in a few weeks.

I have a large deck ready for the platform, but I need to draw on some experience from all of you!

I've been planning on placing 2x4's across our deck joists to act as our floor support. This will essentially be the structure for our 24' circle platform sitting on top of the deck joists.

What's the best way to place and then cut the 2x4's on top of my joists (they will be put at 16'' centres) so that the edges of the 2x4's conform to my 24' circle? Do the edges of the 2x4's need to be curved?

Much Appreciated,
Nick

[Bob Rowlands]

I'm not really following what your plan is here are asking. I don't see how that floor framing will end up being circular? If I were you I'd go ahead and deck that with 2x6s or TREX and then build a circular platform on top. Maybe I'm misunderstanding something here?

[Nicholas Russell]

Hi Bob,

I should have been clearer, sorry. These are the floor joists in the picture - I've yet to put on the 2x4's to be the support for a circle platform. The 'platform' will sit on top of joists.

Alternatively, I have been considering making a big 'sandwich' of plywood - high-density foam - plywood. And simply cutting this into a circle.

Any input on either idea would be much appreciated.

Cheers,
Nick

[Bob Rowlands]

Me, first I'd block the 2x10s above the beams, cover that framing with 2x6 decking, and then build a circular

yurt platform

atop that decking with a second layer of 2x6, laid flat, and cut to a 24' circle. Edge band that with 1/2" plywood. That would make your floor 3" thick. Stop drafts and bugs and be the worlds most solid wood yurt floor. lol I overkill everything. I just made ell brackets and attached to my low lath cross and to the deck with screws. Bombproof.

If you are thinking about floor panels, that's a good idea, but still really need to block the lower platform above the beams.

In my view, stacking floor framing atop floor framing isn't a good idea because of hingeing. Toenailing one set of framing set perpendicular to the next won't stop a hinge from developing. To stop hingeing block the 2x10 framing at the beams.

If you really wanna go with a second 2x4 frame atop the 2x10s just go for it. Ontario isn't earthquake country and the terrain your platform is sitting on is flat. Unless there is frost heaving you'll probably be fine.

As for outside platform circle detailing, block between the 2x4s at the outside edge once cut to finished length. Don't let any of the 2x4 platform framing stick out past the 24' diameter. Block between all outside cut edges. Deck with 2x6 and cut the flooring to the circle. Install the 1/2" band to the upper 2x6 circular decking, not the blocks. Since the flooring is curved the blocks don't need to be. That probably answers one of your questions.

You're doing good. Have fun.

[Nicholas Russell]

Thanks Bob,

Lot's to think about, thanks.

Some contractor pals of mine are thinking it would also be interesting to forgo any 2x4's at all and just put hi-density foam in a 24' circle covered with 5/8" T&G plywood. This insulated circle, capped with the 5/8' ply would sit on top some OSB (which would lay in a circle right on top of the joists you see in the pic).

The foam is rigid enough to carry the weight down to the joists and with the thick T&G plywood on top it would be plenty strong. The foam also has some sort of coating so I wouldn't need vapour barrier, I'd just tape the big panels together.

Basically, it's a huge SIP. We'd screw the plywood right through the rigid foam into the joists to fasten.

Any thoughts on that?

You're right about our location; high ground, even, with not too much

moisture

, I don't suspect frost heave to be too much of an issue.

Cheers,

[Bob Rowlands]

You could just go for it and see how it works? I don't know offhand why it wouldn't. I always think about

moisture

retention rotting materials. Ma nature takes out everything eventually. Plus I think mice make nesting or even nests in styrofoam

insulation

. Just some more things to investigate before spending time and hard earned money. Good luck.

[Bob Rowlands]

I have an old car parked in the field around our house, been sitting there for a few years, thought my granddaughter might want it for first car. (Ummmm....no thanks Papa. lol) I recently started it and found evidence of mice - get this- chewing through rubber vacumn hose in engine compartment. What the heck? I would have thought rubber would kill the little buggers. Mice nest in air filter box, plus numerous wasp nests. Critter condo. lol