Platform Blocking

[Bernduffy]

Hello friends. I am about to begin building a platform for a 20 foot Pacific Yurt. Their suggested plan has 4x6 beams 4’ apart and 2x6 blocking also 4’ apart to support 1 1/8” 4x8 tongue and groove plywood.
I’ve built some foundation and floors and feel the suggested blocking is too far apart.
What do you think?

[TSRalex]

Originally Posted by Bernduffy

.....20 foot Pacific Yurt. Their suggested plan....

Do you expect, that each user now is evaluating information about these platforms? 🤔

A proper request should IMHO provide details and easy possibilities for readers, isn´t it?

[Jafo]

Hmm, I left my Pacific Yurt book up at the yurt camp so I can't verify the plans they gave me for my 30' yurt, but I seem to recall that was 2' no? Maybe it is different for the 20' plan.

[Bob Rowlands]

I'd go no wider than 2' with that 1 and 1/8th subfloor regardless of what they suggest. A 4' span is gonna be a WHOLE lot more lively than 2' centers. Additionally I'd use new style 2x6 joist anchors that feature toe nailing ports. VERY solid and of course code approved.

[Bernduffy]

That’s what I was thinking, Bob. I know 1 1/8 ply is pretty stiff but a four foot span is trampoline time.
Here’s the plan url
https://www.yurts.com/download/20-platform-plans/

[Bob Rowlands]

Here's a 'span' story for you. I've lived in the same city since 1962, minus 4.5 years up in Jackson WY.

Back in the 1970s when I was framing full time here in the Springs I worked on a brand new commercial strip mall, on Academy boulevard, a major thoroughfare here in town. Dairy Queen anchored one end.

We roofed the block building with XXXX style flat metal trusses that spanned 50' front to back, on 4' centers. 2x4 on top and bottom chord of truss to fasten sheathing and mechanicals to. The sheathing was -now get this- 1/2" plywood spanning trusses 4' (!!!) on center. Not 2', 4'. I'm not making this up. We installed 'H' plywood clips at 12" intervals between the 8' butting edges of the plywood courses, so there were three clips between panels every 4' bay. Those clips were common back then on 2' residential truss centers. Them days is LONG gone.

That roof WAS a trampoline. The whole crew would get to laughing as we bounced around on it installing the plywood. Without any doubt 'THE' liveliest roof of all time. How that got through regional building dept, and passed inspection beats me.

What's really even more amazing is 45 years later that building is still there and I don't believe has ever had the structural roof redone. Re-tarred, yes. That was a very shallow pitch composite hot roof covered with FESCO board, roofing underlayment, tar and gravel. Done a few tar roofs including 13 residential Grand Teton National park staff housing redo in Moose WY up by the Park, for solar mounts back in summer 1982. Worked with a dumbass named Delbert that popped a tar ball in his mouth and chewed it. Del wore cowboy boots with shorts, had a passel of kids and lived in a trailer, and had a great sense of humor. Now THAT's a construction worker right there folks. haha

What's most amazing is my incredible memory for details a half century ago, huh? haha

Good luck with your platform.

[Bernduffy]

Great story Bob. Yeah I’ve bounced around on some roofing that had me as nervous as a long-tailed cat in a room full of rocking chairs.

Pacific Yurts

plan is probably okay but I usually overbuild.

[Bob Rowlands]

Me too. I'm notorious for it.

[Ivan]

the plan i received when building my 24 ‘ Yurt had the beams at 4’ apart, with flooring 5/4” t&g . no bounce so far. the T& G is where the strength is. in fact I have seen many Post and Beam houses with exposed 2 nd floor beams at 4’ , as you can see the underside of the 5/4 T&G when l from the 1 st floor .

[Bob Rowlands]

I've lived in, and worked on, a couple houses that had 1.5" x 2x6 T@G flooring on 4' center beams, with no underlayment. This is in post and beam apt. building, and residential loft area where the frame and flooring were visible from the main level.

It was noisy. Our apt. in Jackson WY was post and beam, and had that flooring with carpet on top. No deadening board or other it was built before modern codes. Noisy. We could easily here the action above our bedroom. The folks below us must have had ear plugs on the night stand. hahaha


4' span has gotta be max. span for that material in that application. I'd think in a yurt it would get drafty and buggy in addition to squeaky, down the road.