Are 3/4 inch EMT poles strong enough?

[captain voltaveus]

I am curious what the community's experience has been with EMT flat roofed structures made from 3/4 inch EMT conduit vs. 1 inch. It seems like the cost for materials will double if purchased new...

Thanks!

[MFOB]

Depends on what you consider using the Flat Roof for.

If you use it to build a cube per se that only supports a Shade Cloth or something like that, that would be fine. It will only support a little weight. But it will be flimsy and rickety. You'll have to get creative with a way to secure it so it doesn't fall over by itself.

If you're going to put any weight on top of it or introduce any additional loads to it, it will more than likely fail. Keep the spans as short as possible and you can do more with it. A 10' span of 3/4 will bend a bit under its own weight. 1" would be way better.

[danibel]

OMG no. One of my campmates bought 3/4 last year and wasted their money. The footies for that size do not fit rebar for anchoring. I believe the EMT poles I have from Black Rock Hardware are 1.5. They are heavy, but I would't worry about weight/cost. I would worry about the actual use.

I don't have to use footies, as the system I bought has set nuts welded in the legs to secure to rebar, but if you are going the footie route - make sure yours can be anchored properly!!!

[MFOB]

You don't need to anchor the bottom with rebar.

Attach a ratchet strap or the like to the top corner and guy it out at 30-45 deg. Then attach that to the rebar. The pressure you create with the ratchet strap will dig the bottom of the bars into the Playa about 1-2" and will be secured by natural means, then the ratchet straps will hold down the entire structure. That's how we've done it in years past and it works really well, and you don't have to pound so much fn rebar. We have a 20x20 shade structure made out of EMT.

[The Rod]

Better yet, use lag bots. Then you have to pound no rebar.

If your structure is sufficiently guyed you don't need to secure the poles to the playa. You do however want to keep them from sinking into the playa, maybe use feet made out of 1 inch plywood scraps.

[captain voltaveus]

Thanks, sounds like 1 inch EMT is the way to go. I'm planning on repurposing Alumanet shade cloth from last years structure. It held up, but I was always a bit sketched out when leaving camp and found myself coveting my neighbors flat roofed EMT system.

Any tips on cheapest place / burner friendly to source the connectors?

I used fig jams lag bolt system last year with mixed results I must say. My impact driver didn't seem to do a great job of driving in the bolts, but I bashed them in with a sledge and the worked fine anyway...

[Elliot]

...
I used fig jams lag bolt system last year with mixed results I must say. My impact driver didn't seem to do a great job of driving in the bolts, but I bashed them in with a sledge and the worked fine anyway...

*Good Dawg. Where is our face-palm smiley?!*

Then you did not use FIGJAM's system, because that entails screwing the lags in with an adequate driver. (But I'm glad nothing blew away anyway.)

[LionsNzebras]

We got our footsies, tarps and balls from here
http://www.ysbw.com/
We like this one because they have a lot of parts and you can design your own shade structure and not have to use a standard square if you dont want to.

Our one inch emt is cheep 7 bucks a pole. If you can find a local electrical contractor you will get a much much much better deal than any local hardware store like Home Depot. Our local price is over 11 bucks each, its almost double the cost at Home Depot.

Use figjams lag bolt discussion 14-18 inch lag bolt 3/8 or 1/2 with 2 washers and a few links of chain, drive it 1 inch below the playa surface. As discussed in this thread its important to make sure your driver can deal with this, as you found out last year, plan plan plan, then redesign and plan again!
Use ratchet straps to hold it down.

At least this is our plan, we will see how it all turns out next year.

Would much rather over design a structure and spend more money, than to have the guilt of hurting anyone with my shade structure bellowing through their camp.

[Token]

The length of your strut will determine the size and thickness required to minimize failure.

No canned answer is possible.

If you really want to minimize the risk of failure, you can't use conduit as it is not structural. Basically the cheapest reject recycled steel available goes into making conduit.

Minimum 1 1/4 inch schedule 40, 1 1/2 inch even better, you know, scaffolding iron.

But good luck with the conduit. Ton of folks get lucky each year and never get hit by the big-ass dust devils.

[TomServo]

3/4 is fine for a small structure..secured to vehicles.

[trilobyte]

I've built 3/4 inch structures in the past, but never again. They start to get dicey when the winds get in the 50-75mph range, and then not only are you stressing about that and scrambling to get back to camp when a big storm kicks up, and you wind up having to replace bent poles even when the structure doesn't fail on you. From my experience it's well worth the added cost to step up to 1 inch fittings and conduit.

While conduit is not structural steel, I've found the 1 inch stuff, when designed/built right, can easily handle anything the playa dishes out. My structures have seen some rough weather and direct hits from big dust devils without batting an eyelash.

[vantim]

How about conduit for a tensile structure? I'm re-thinking my shade structure due to the long distance I have to travel from Vancouver, Canada. If I'm using a 30x30 piece of shade cloth, held up in the middle by a pipe or plank, would 1 inch conduit work for the edges or would I need to go up to 1.25 or 1.5? I would put conduit 6-7 feet tall at the corners and halfway down each side, ratcheted to bolts in the playa.