DIY PVC Hoophouse

rininger85

I've been looking around for examples of what people have done to build hoop houses and it doesn't seem like there are many who document the entire process (not on forums anyways, I've found a few on youtube that are good examples) for people to find in the future who feel like embarking on the adventure of building a hoop house, so I thought I would start a new thread and document my build along the way.

I have already built a small 16x16 stick built "winter greenhouse" that I am running an aquaponic system in, I have a separate thread for that here so I won't go in to a lot of details about it in this thread, but being 16x16 and trying to run it year-round I have a lot of lost space to house water barrels, the fish tanks for the AP system, etc. So when it came to starting seeds this past spring we had seed trays set everywhere we could possibly set them and just didn't have enough space, so now that I have pretty much finished that project my wife and I decided we would put up a larger hoop house in the garden.

Phase 1 of this greenhouse won't include AP, but eventually I think I might be able to sneak it in (I will at least have an IBC in there from pretty early on that I can use to put my fish tank water from in my house in then use it to water the beds in the hoop house so I guess in that sense it is kind of an AP wicking bed idea... time will tell if fish manage to find their way in to that IBC or not (don't tell my wife!) =)

rininger85

First the planning stage. I am a mechanical engineer by trade so everything I ever build starts with a 3D assembly to create my parts list and to plan out my space.

Being that the hoop house will not be quite as secure as the smaller greenhouse I decided it needed to go inside of my garden fence. So initially I drew up a 16x32 hoop house which took up most of the free space in our 44x46ft garden fence aside from the existing raised beds (shown in brown). So once I showed the idea to my wife she agreed that I needed to extend the garden fence out... luckily aside from having to pick up a few more T-posts I had enough fence left to extend the garden over another 16ft so now the garden will be 60x46ft and I won't use up all of the space that we currently have vine crops planted in the ground. The other thing the wife decided was I should maximize the length since it wouldn't cost much more to extend the hoop house further, so it will be 16x40 instead.

One concern that I have had with PVC hoop houses is will it hold up to our northern winters / wind storms. I found a few examples of them surviving wind and snow, but I'm not sure if any of the examples have been as bad of winters as we get for snow or not. So I am planning on running a beam down the center of the hoop house to give the hoops support at the top, as well as the perlins and knee boards on the sides to tie everything together. I looked in to how much weight a 6mil greenhouse covering will hold and found one supplier tested it using about a 5ft section and it held about 580 pounds in that 5ft section, so I am comfortable that the plastic should hold up against wind and snow at least long enough for us to go out and clean it off.

rininger85

Step one, reclaim part of the overgrown field to add on to the garden... brush cutting attachment on the weedwhacker hacked everything down, then hit it with the mower up high, picked up rocks, hit it with the mower down low, picked up rocks again.

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Step two and three, extend the garden fence out to protect the new area. Cover ground with plastic / weed mat to kill the weeds.

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I plan on purchasing the lumber and PVC this Thursday, but it will probably be next week before I start building (going away for the holiday weekend)

SeanD

Mel Redcap documented building hers in her build thread http://www.backyardaquaponics.com/forum/viewtopic.php?f=18&t=26865

Unfortunately a lot of her photos have stopped working

It's not cold enough here to be bothered with a greenhouse, but I do have a similar frame with bird netting over my fruit trees.

The first windy day after it went up I was convinced it was all going to get smashed but it survived.

Good on you for sharing what you've learnt.

dasboot

Sensible ideal having the centre board it really does give a huge amount of strength to the hoop house,another thing I would do if you can get cross piece fittings is run another pvc end to end to stop individual pieces from flexing,I hope that makes sense.
My hoops have all lasted well through the violent tropical storms,apart from when I used inferior covering,this ripped and took off in the wind taking just about everything with it,a lesson again learnt the hard way.

scotty435

Caterpillar style tunnel is another option. This Greenhouse has been through a few revisions and has very detailed instructions including site preparation and installation of a split vent - The end wall is a separate set of instructions -

https://www.noble.org/news/publications/ag-news-and-views/2011/december/the-noble-foundation-poly-pipe-hoop-house/

Instruction PDF
https://www.noble.org/globalassets/docs/ag/pubs/horticulture/nf-ho-12-02.pdf

This is also an excellent publication and in addition to linking to instructions for the greenhouse above, it has a link for a different style as well.
https://web.extension.illinois.edu/bcjmw/downloads/54183.pdf

rininger85

Thanks SeanD, I did read through Mel's build a bit before the picture links broke (argh photobucket! I have never liked photobucket!). Comparing climates I think we're likely to see a lot more snow than she does which necessitates the center beam for me I think. The gent down the road from me has an 8ft x 40ft PVC hoop house which I don't recall him having any extra supports on, but since I'm going twice as wide I am going to add them because I'd rather spend an extra $50 on lumber now rather than regret it in 4 or 5 months.

Dasboot, I just finished going through your thread, definitely an inspiration. I had noted how you had the T's in connecting your PVC pieces together. I was planning on adding either PVC or 2x2 / 2x4 wood purlins on the inside of the hoops for more support half way down both directions from the center brace (didn't put it in the layout). I am worried that the PVC fittings might be more likely to break after repeated heating/cooling of our winters here, so that I why I thought I would just do purlins on the inside rather than T's and crosses between hoops. In addition to the purlins to tie the hoops together I will have knee boards probably about 3 feet off the ground to be able to roll the sides up for air flow in the summer. Additionally I think I can buy a 10 foot piece of 1.5" PVC electrical conduit ($5.22) for the same price as one or two 1.5" PVC crosses... so it should help keep the cost down too -- just reading through the links that scotty provided they say NOT to use PVC for their "split vent", but I think the problem looking at what they did was that they used regular PVC which is not UV protected, whereas the electrical PVC is supposed to be UV stabilized because it is normally exposed where PVC water pipes are usually hidden so they don't need UV protection.

scotty, I'm doing the caterpillar style over my raised beds in the garden, but I don't think I want to go that route with this bigger structure. I think even with a normal vent on the bottom of the tunnel I will probably add wiggle wire channels are the bottom to be able to lock the sides in place for the winter then be able to remove the wiggle wire in the summer.

I do like their split vent idea, but wonder how much heat will be lost in the winter time from that split (maybe I'll see that the temperatures are too cold in the winter time to really worry about it). I don't think I'll need to vent it much for the winter, but I'm still learning so I might learn the hard way. I am going to put a couple of house windows in each end of the greenhouse for additional ventilation in the summer time on both ends (I have quite a few windows in my barn which I have no other use for, my dad saved them when he replaced them in houses for people so I've already used some of them in my other greenhouse, should have 4 matching windows I can place in the ends.

rininger85

So I try to be a man of my word... Went and picked up most of the materials needed for this project tonight. We are going to my in-laws tomorrow night, but my wife said she wants to come home Sunday night instead of Monday (U.S. labor day holiday) because she needs to go in to work to water plants in the greenhouse at work Monday for her whole department, so that means I should be able to start assembling the hoop house Sunday night or some time Monday.

I'll post a parts list and prices for materials tomorrow, for now, gotta love the flexibility of my Avalanche for hauling materials!

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Those are 16ft 2x8s in the middle, only stick out past my tailgate a couple feet...

dasboot

Dasboot, I just finished going through your thread, definitely an inspiration. I had noted how you had the T's in connecting your PVC pieces together. I was planning on adding either PVC or 2x2 / 2x4 wood purlins on the inside of the hoops for more support half way down both directions from the center brace (didn't put it in the layout). I am worried that the PVC fittings might be more likely to break after repeated heating/cooling of our winters here, so that I why I thought I would just do purlins on the inside rather than T's and crosses between hoops. In addition to the purlins to tie the hoops together I will have knee boards probably about 3 feet off the ground to be able to roll the sides up for air flow in the summer. Additionally I think I can buy a 10 foot piece of 1.5" PVC electrical conduit ($5.22) for the same price as one or two 1.5" PVC crosses... so it should help keep the cost down too -- just reading through the links that scotty provided they say NOT to use PVC for their "split vent", but I think the problem looking at what they did was that they used regular PVC which is not UV protected, whereas the electrical PVC is supposed to be UV stabilized because it is normally exposed where PVC water pipes are usually hidden so they don't need UV protection.[quote][/quote]

That sounds like a plan,you are right about the pvc fittings they do suffer from being in the sun and heating and cooling,when my roof let go nearly all the fittings in the sun broke in some way another,the shaded ones if I recall there wasn't a broken fitting.

dasboot

By the way lovin the pickup,I looked at a Nissan Navara yesterday,five years old and only 31,000 miles on it,the seller is a farmer and has two other pickups and as he says he hardly uses the Navara so it's up for grabs,it's bloody dirty though,not how you would normally present a pickup for sale. Still looking through the muck it's got to be a winner comes with all the extras as well.

SeanD

I have a Navara, and I hate it!

But in saying that it does it's job

Which model is he selling? Some are better than others

scotty435

Here's that end wall construction plan I mentioned - https://www.noble.org/globalassets/docs/ag/pubs/horticulture/nf-ho-11-01.pdf

If you want to get really fancy on the sidewalls you can use Polyvent II or III so that the vents are inflated by a small blower motor. When the motor goes off the side vents open. If I remember right, the difference between the versions is one is either open or closed while the other has two different open settings. If you go this route check first with the supplier to see if it will work with the PVC hoops.

Polyvent II
http://www.greenhousemegastore.com/product/poly-vent-ii-sidewall-system/greenhouse-cooling

Polyvent III
http://www.greenhousemegastore.com/product/poly-vent-iii-natural-vent-system/s

As far as the heat loss from the split vent :dontknow:

. If you cover the first section of side at each corner that should help reduce the air getting in at the end of the vent and the sections overlap in the middle but still tough to say.

rininger85

Das, the thing that is nice about the Avalanche is that it is a 4 door, so you get the convenience of the extra long cab, but the back seats fold up and there is a mid-gate which folds down so you can still fit 8ft long sheets in and still be able to close the tailgate. I can actually fit 12ft boards in without a problem and still close the tailgate if I don't have too many of them, I can run them up over the center console and right up to the windshield on the front. The 16ft boards in the picture I had ran up to the dash but did not set them on the top of the dash because they are pressure treated and very very wet so they are very heavy, didn't want to have them sit on the plastic dash. I have been continuously impressed by how much I can fit in the truck. I had posted a picture in my other thread that showed about 30 sheets (4ft x 8ft) of 1 inch styrofoam stacked up, then something like 26 rolls of fiberglass insulation (not all of the fiberglass rolls fit, I had to sit some of them on the tonneau cover and strap them down). I've helped people move and I can pack a LOT of boxes/totes in the truck and still close it up tight so it doesn't matter what the weather does nothing will get wet! I had a Chevrolet Silverado work truck prior to this, it was a single cab with an 8ft bed and I just love the Avalanche compared to the Silverado (it's got a lot more bells and whistles than the Silverado did too comparing a WT (work truck) to an LT package so that is part of it I suppose...

Scotty the other thing I've considered is that I may eventually add a second layer of plastic to be able to inflate it and make it a little warmer / better insulated in there. I'm not going to do that this year, so I'll have to figure it out later what I decide to do, for now I just want to get the main structure up before winter so it is ready to start seeds in the spring. I will get some temperature readings through the winter and see what it does this year.

rininger85

So here is my materials cost so far...

Home Depot:
(28) 2x4-96" (not treated) $3.53 each = $98.84
(2) 2x8-16ft (treated) $18.88 each = $37.76
(8) 2x8-12ft (treated) $14.27 each = $114.16
(12) 2x4-10ft (not treated) $4.81 each = $57.72
(28) 1.5" Schedule 40 PVC Electrical conduit $5.22 each = $146.16
(1) 5 pound box of 2 1/2inch torx head deck screws $23.48 (I pay extra for these just because they are so much nicer to work with than phillips screws that they push over here).

so far the total is $478.12 for materials plus $28.69 (6% sales tax) for uncle Sam brings my overall total to $506.81

I will need to buy 8 sheets of plywood that I did not get yet, as well as the greenhouse poly that I have not ordered yet. I'll update the materials list and cost once I get those. For now this will give me enough to get most of the structure up. (I am estimating $80-100 worth of plywood -- I might have a few sheets lying around that I can use, have to look... and about $200 worth of poly, so I should be right close to $800 total for this hoop house at 16ft x 40ft (4.8m x 12.2m) is my current estimate)

rininger85

dasboot, I just ordered some of those sponge cubes to try out but I think I'll need to find something cheaper in the long run. I can order them for $12 / 100 and have them shipped here from Thailand but it will take a month to get them, or I could pay $10 / 48 and have them in 2 days... so I paid the $10 to get them in 2 days for half as many. I guess if they work easier for me then I will know to order them in advance if I have to get them shipped from Thailand, or see if I can source some other type of sponge material here and cut my own cubes if I need to.

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