Hoop house construction thread

1 3/8 in x 10 1/2 ft 17 gauge galvanized steel top rail


Hoop bender or


1 1/2 in x 10 ft Sch 40 pvc


45 degree bends/fittings




Reference
High Tunnel Hoop House Construction Guide Spiral-bound – 2015 by Steve Upson
High Tunnel Hoop House Construction Guide Steve Upson

Roof design for vertical load rain and snow without center support, basic design, dual layer insulated.

In my yard, that would be a box kite.

Simple pvc bowed and plastic over a raised bed....viola....hoop house!

I prefer not using PVC due to the off gassing issue caused by the old style PVC lined grow tents.


I found out recently, in an article I was reading, that what was being off gassed was chlorine gas. Personally, I wouldn't want that in my GH.

I use 12-15' trampoline frames, that I pickup and collect for free off FB marketplace and craigslist. I lost count how many Ive gotten over the last year or 2.

1 frame makes 2 beefy arches when split in half, and sometimes they come with the safety net poles which I use to connect the arches together with the same brackets that the leg posts go in.

Would cost a fortune to buy thicker pre bent galvanized metal like that. I've picked up 3 free ones at a time on a good day, usually because they have a hole in the bounce pad. Sometimes the pads are good and i could probably sell the ones that are and make money, or a good tramp out of 2 or 3, but thats never been my plan.

3 same sized frames = 6 arches, if they are spread out by 3 or even 5 feet you could go 30' long by whatever diameter they are.

I pound 6ft. Heavy duty metal T-posts deep in the ground and then use straight pipe around them to make the walls taller before I set the arches on.

Then I drill a small hole right through the pipes and T post and put a bolt through each one. Youll definitely wear out a few bits if doing alot. I use teks metal screws to screw everything else together. Sometimes Ill buy top rail but have so many 2' straight leg posts I just screw them together for longer peices.

My diy tramp frame GH and carports held so much snow over the last month. They even self clean themselves as the temps warm up. Meanwhile half the people I know have those $200+ car canopy tents collapsing lol.

Im planning a 15' wide by 30-40' long structure right now, just need 2 more free 15' trampolines. Its taken me a year of scouting out free ones though, but very little gas money and time once I get ahold of people. By the time you collect alot you have 12s, 13s, 14s, and 15s.

Its a great way to make smaller greenhouses if you dont wanna spend much and have free time, you can fit them in a car trunk if broken down all the way.

I would most likely bend top rails if I wanted to get it done quick and make multiple large GH's..


Even if you already had or were to find one free trampoline, you could set it up to bend top rails around it.

Heres the vids that I got the trampoline jig idea from, hope it helps!

https://m.youtube.com/watch?v=dSFk5Rn5rGA



EDIT: looks like he updated his method
https://m.youtube.com/watch?v=vScCOXZRaeY

1 3/8 top rail all the way. Pvc is just to flimsy. 1.5" pvc is the same price as top rail. You don't need those vertical supports for top rail. You could add some trus supports if u wanted.
Only reason i would ever use pvc is for a quick and dirty SMALL temporary hoop. The chloride in The pvc will rot your plastic cover. The warranties on greenhouse plastic yellowing are void if you put it on pvc. You can't really attach wiggle wire channel to it. Every pvc house i have seen has saggy plastic. The pvc is really brittle and easy to crack after a summer in the Sun. Try cutting pvc with a pipe cutter after it's been in the Sun for a summer. The blade doesn't cut through. The pipe just cracks.

I have a thread on top rail greenhouse building but most pictures are gone now. There are some really great instructions around The web though for different designs.

While I wouldn't really use PVC for a permanent greenhouse frame either, surely you could paint it to protect from UV's if you did.. and probably even prevent off gassing to some extent..

I connect my hydroponics systems together with PVC, as do many folks, even in greenhouses. I just covered the pipes with foam insulation, but that stuff degrades too. A can of spray paint can go along way to protect it i'm sure.

I have a load of 4x4" vinyl fence post sleeves I was gonna make a chicken coop roof top NFT lettuce growing system out of.. was thinking a coat of metallic looking paint on the rails, to match the galvanized metal roofing would work well. Anyone think I should laminate them with something instead? It's gonna get hotter than normal up there, until its covered in heads anyway, and hoping it will keep the chickens from roasting as well as feed them in the hottest part of summer here. I thought about using henry's elastomeric aluminum colored roof coating too, might work good.

Indoors I don't see a problem, but greenhouses/OD for sure, the sun don't mess around!

h.h. said:

In my yard, that would be a box kite.

Click to expand...

100mph+ winds are no joke... I've seen a few get destroyed over the years.

Drop That Sound said:

While I wouldn't really use PVC for a permanent greenhouse frame either, surely you could paint it to protect from UV's if you did.. and probably even prevent off gassing to some extent..

I connect my hydroponics systems together with PVC, as do many folks, even in greenhouses. I just covered the pipes with foam insulation, but that stuff degrades too. A can of spray paint can go along way to protect it i'm sure.

I have a load of 4x4" vinyl fence post sleeves I was gonna make a chicken coop roof top NFT lettuce growing system out of.. was thinking a coat of metallic looking paint on the rails, to match the galvanized metal roofing would work well. Anyone think I should laminate them with something instead? It's gonna get hotter than normal up there, until its covered in heads anyway, and hoping it will keep the chickens from roasting as well as feed them in the hottest part of summer here. I thought about using henry's elastomeric aluminum colored roof coating too, might work good.

Indoors I don't see a problem, but greenhouses/OD for sure, the sun don't mess around!

Click to expand...

I'm not sure how much protection paint would provide against heating the PVC. Heat is what causes the off gassing.


On the FAQ page of the DIY greenhouse site I visit they recommend placing a barrier in between the plastic cover and a PVC framed GH. Warranty is void without a barrier on PVC framed tents.

h.h. said:

In my yard, that would be a box kite.

Click to expand...

3 ft buried posts help prevent that.


Renting/purchasing/building a post driver is key.

Drop That Sound said:

I use 12-15' trampoline frames, that I pickup and collect for free off FB marketplace and craigslist ...

Click to expand...

I like the trampoline idea!

aridbud said:

Simple pvc bowed and plastic over a raised bed....viola....hoop house!

Click to expand...

CrushnYuba said:

1 3/8 top rail all the way. Pvc is just to flimsy. 1.5" pvc is the same price as top rail. You don't need those vertical supports for top rail. You could add some trus supports if u wanted.
Only reason i would ever use pvc is for a quick and dirty SMALL temporary hoop. The chloride in The pvc will rot your plastic cover ...

Click to expand...

I agree about pvc being convenient for quick, temporary hoops. Even a simple row cover can add weeks to the growing season with frost and insect protection.

MJPassion said:

I prefer not using PVC due to the off gassing issue caused by the old style PVC lined grow tents.


I found out recently, in an article I was reading, that what was being off gassed was chlorine gas. Personally, I wouldn't want that in my GH.

Click to expand...

CrushnYuba said:

... The chloride in The pvc will rot your plastic cover. The warranties on greenhouse plastic yellowing are void if you put it on pvc. You can't really attach wiggle wire channel to it ...

Click to expand...

Adequate ventilation should prevent immediate off gassing issues within the greenhouse. Strips of adhesive backed material can also separate plastic film from contact with hoops.

Douglas.Curtis said:

100mph+ winds are no joke... I've seen a few get destroyed over the years.

Click to expand...

100mph winds = 100 free ripped up trampoline frames posted on craigslist the next week

Posts may be spaced approximately 3-5 ft apart.

Rigid end walls, diagonal braces and ground anchors add strength.

1 3/8 in x 10 1/2 ft galvanized steel top rail $10.60
1 1/2 in x 10 ft Sch 40 pvc $6.40
2 in x 4 in x 8 ft wood stud: $2.60

You need more then 2x4 i think for it to be sound. You need a wood frame that is the structure of it. The pvc doesnt provide much structure. The pvc just holds The plastic up.
The only pvc greenhouses i have seen last over a year are built just like pole barns with 4x6 beams and posts. They basically built a pole barn and then screwed 1" pvc to it and covered it in plastic. My buddy has replaced the pvc a few times over The years. You have to have a solid wood structure that is free standing that you then put pvc on. Think of pvc as part of the cover instead off part of the structure. Most people just replace the pvc and poly every year or 2. If you found a way to coat The pvc it could last longer.