shade cloth monkey hut sanity check

[meeotch]

It's been about thirteen years since I've built one of these, so I'm hoping to get a sanity-check from the masses on our design. See pic here: [img]http://houseofpain.org/xfer/blind/tubey_v8a_crop.jpg[/img] Stats below. Feel free to ignore the nudeness and hugeness of our stand-ins. We are much less nude and ripped in real life. In fact, nearly none of each.

19' diameter, 18' length, 9.5' height
2" diameter PVC tubing. (overkill possibly, but I like it)
4x 30' circumference arches, made of three 10' sections of pipe each, connected by extra-deep couplings, spaced every 6'
3x 20' horizontal "spines" (two 10' sections, regular couplings). Zip-tied or inner-tubed onto the arches (not connected with T or X couplings), these could be a smaller diameter pipe - maybe 1-1/2"
2x 20' "ground spines" that are only there to attach the shade cloth to.
covering is 90% knit shade cloth, light tan color
550 paracord for guy lines

Some specific questions:
1) will the 90% shade cloth be sufficient during the day? Someone suggested that UV protection will be sufficient, but visible light may not.
(We'll have a 20'x20' rain tarp standing by, but if we have to tarp the thing the whole time, there's no point in blowing money on shade cloth.)
2) will 90% shade cloth catch too much dust/wind? Or be so hard to see through that it might as well be a tarp?
3) what sort of forces can we expect on the guy lines - is 550 paracord sufficient? (Knot suggestions welcome.)

We'll be testing this ahead of time, obviously - but since we're all from the east coast, we've only got one day post-flight / pre-burn to work out the kinks.

[Jackass]

I would opt for a tarp myself, the monkey hut is designed to handle all sorts of wind loads. With the cloth you don't get complete sun protection, you get less wind protection and (in case it happens again this year) you have absolutely no rain protection. That's my take on it, individual experience may vary.

[CapSmashy]

Shade fabric does a good job at cutting down the wind and helps keeps the dust down and 90% will offer plenty of sun protection.

The Booby Bar domes are covered in 70% shade and do a remarkable job at creating a shady space that is relatively dust free even during a whiteout. Wind gust will shake some loose here and there, but it does a surprisingly good job.


Also, with a tarp, all you will hear all day and all night is that oh so wonderful "kerflap, kerflap, kerflap" sound that tarps make in the wind no matter how well they are secured.

[Jackass]

Also, with a tarp, all you will hear all day and all night is that oh so wonderful "kerflap, kerflap, kerflap" sound that tarps make in the wind no matter how well they are secured.

I use billboard vinyl for my hut and it makes no such noises, but the tarp also weighs a bunch more than a blue or even a silver tarp. No trash bag in the wind style noises with this stuff.

[CapSmashy]

Yep, billboard vinyl is a different animal entirely.

[some seeing eye]

I have used 3/4 for the arches and 1/2 for the lateral stabilizers-spines & bottom tarp tie off. My arch was smaller, 20' circumference, no arch joints.

-Agree probably solid HD silver tarp and some suggested structural upgrades rather than shade cloth, especially with a vehicle closing one end. If you tarp just make it 20' long rather than 18' and then you could use 2 20x20 tarps.
-I would add a top spline.
-Suggest 20' tubing lengths, rather than 10, especially since the arch through the joint may not be smooth
-I have seen large diameter pvc for arch web domes (don't know the supplier) but it seems overkill and is it flexible enough to arch? I have been able to reuse the pipe for sprinklers and around the home buried use.
-I use cheap Home Depot rope and ball bungies at the grommets.
-Use at least 1/2" rebar at the arch ends. I used 3', 18" in the ground and 18" above. That may be a precut Home Depot item. I had fun driving it with a demolition hammer (ask around to borrow) but it was a *&&*^ to get out (see if you can borrow a stake puller)
-The over the arch tie downs should follow the arches, bad idea to attach to the side spines. Also try to attach the arches to the rebar/ground to keep the whole thing from airborning. (I wrap a couple tye-wraps around the rebar ridges and a couple through those around the bottom spline and duct taped to the arches)
-1" schedule 40 pipe is $6/20', so I would increase my arches from 4 to 7 (6' spacing to 3' spacing) and decrease to 1" or 1 1/4" you can judge by looking at the store. White pipe, not black.

Take some pics of construction details for future e=playaing and have fun!

[meeotch]

Thanks for the responses. I'll reply to a couple of them, as some of this is stuff we've considered previously:

Tarps - we were really trying to steer away from tarps, for the noise/wind reasons mentioned, and because it's completely opaque. Also, it means more tensioning of the whole thing from the edges, rather than tying the covering directly to the arches & spines. Though I do wonder whether this (tensioning) makes the whole thing stronger, by spreading out external pressure across the whole surface... and whether that's a bigger win overall than having something the wind can blow through a bit. (w.r.t. rain - we'll have a tarp & bungees ready, as mentioned, but weren't planning on it being a structural element.)

Along the same lines, I wonder whether more arches & thinner pipe would be better at spreading the external pressure. I assume so, but I also don't like the way the super-thin huts squash & stretch. I believe we used 2" when we built a larger hut back in '98, but I don't remember for sure - nor do I remember the arch spacing.

Other odds & ends:
>> I would add a top spline.
There is one. May not be clear from the pic. There are three total.
>> -Suggest 20' tubing lengths, rather than 10
Can't do for transportation reasons. And our source for 10' is actually cheaper than 20'.
>> The over the arch tie downs should follow the arches
That's actually a bug in the rendering - they don't go all the way over, and there should be one at each arch, attached to the lower arch/spine junction.

I guess the arch spacing vs. pipe thickness is my biggest remaining area of uncertainty. Laying it out on the ground, it does seem like a 9.5' radius does make for a significant bend - maybe too much for 2" pipe? I still feel like those 1" pipes are like noodles,though - I was hoping on relying less on "correct" construction, and more on overly strong members, since we have so little time to make adjustments.