Have a 15'X 40' quonset style that fits your description. The frame was $400 back in March,1994 when I put it up. Now, 12 seasons later I still have the same plastic on it. The bathroom ceiling fan that I used as an inflater has quit last year(thought it might last one season). I framed the ends with treated 2x4s and installed double used wooden doors on the entry end and a louvered barn fan on the other end.

My suggestion to you would be to go gothic style just because I believe they are more sturdy. When I replastic mine I will install a wire-lock channel at the base, ends and even possibly 3' up one side to permit roll-up side for ventilation savings. Purchase the galvanized frame since they are not that expensive but avoid extra perlins since you can buy the cross connecters from a greenhouse supplier and pipes at Lowes or Home Depot cheaper. As you might gather from earlier, I'd save money on the peripherals like fans, inflaters and heaters by improvising used equipment.

Erecting the frame should only take a few hours but I'd take the time to square up (equal cross corner measurements) and aviod uneven terrain. The harder part is to install the baseboard and frame in ends.ALWAYS USE ONLY TREATED WOOD. A 2x6" or 2x8" baseboard sunk 2" below ground level should be clamped to each arch and put a tech screw through each clamp into the arch also. The end frames can vary tremendously but I like to have 4x4" posts on either side of the entry door, sunk to below frost level(2'for you anyhow)and connect 4x4" burried to ground level along the entire end. From it I extend a few extra upright 2x4"s ,spaced so as to allow widths for fans, louver openings and flue for your heat source. I use metal plates to fasten the wood to theend frame at the top. They should be cut so as to not extend above the top of the arch, then tech screwed into the arch. When screwing into the wood be sure you have the proper type for treated wood. You can cover your ends with solid plywood, plastic film or any other material. I framed the ends of my larger greenhouses to install cheap auction purchased screen doors and windows. The glass sections from sliding glass doors works great too. Get 1x1" treated strips at Lowes to brace them, sides and top, inside and outside.

When you install your first layer of plastic try to pick a calm day when temps are moderate. Too hot out and the plastic might stretch too much. Install one wire over each layer for convenience (if you go with the wire-lock fasteners). The wire-lock cannals will easily hold two wires on top of eachother. I would clamp two plywood pieces, each with a 4" center hole, together at the spot where you want the inflater, One piece on either side. I prefer the fan on the inside, near the ground near one end. you can cut the plastic out of the center whole anytime later. Wire lock channels also formed around the end arches also is much better than relying on batten strips to secure plastic at ends.

A cordless drill/driver and circular saws are a must for the project. A mitre saw is helpful for framing ends. Also a level (and even laser level) and square are needed. Try to have a few extra hands available when put the plastic on although my wife and i did a 30x96 without too much effort on a calm day. A helpful hint when installing plastic: form softball sized balls or rocks around the one side(foot from edge) every 12-16' with heavy cord tied at the base of the ball. Throw the cords from one side to the next and use them to pull the film over the framework.

Enough said. I'll let others fill you in on their methods.

Thank you, Bmoser, for all of the excellent information! I would love to see pics of your greenhouse. Your instructions for installing the plastic have answered one of my questions completely. I do plan on using Spring Lock fasteners.

Do you keep your greenhouse inflated all of the time, or only when you need the insulation?

I really like your idea for the roll-up side, as one of my main challenges will be to cool & ventilate during the hot Florida summers. Can you explain the system you will devise to actually roll up with side?

The roll-up sides require that you wire-lock the upper plastic film at 3-5' from the ground. You accomplish that by clamping a 2x4" the entire length of the GH at the desired height and screwing a wire-lock base onto it. I purchased 2 different kits for mine but some people will improvise with their systems. For the bottom plastic you could use seperate pieces of film and save a few $$. That section should be 12-16" beyound ground level so you can start wrapping it onto the 1" roll-up pipe. I had trouble with that on my 20x96 GH that relied on plastic clips to hold the plastic on the pipe. I finally put tech screws (self-drilling screws) throught the plastic clips and film into the pipe and that seems to secure it. For my 30x96 GH which I bought used I ordered a wire-lock roll-up pipe--- it has the wire-lock channel formed into the pipe so that once the plastic is secured with the spring wires it won't move.

You have the option of only inflating the upper plastic or both. If you do both you will need jumper hoses and you will also need to heat seam the 2 sheets of roll-up plastic at the ends since the roll-up side are not fixed. This is more complicated for you.I only have double plastic on my oldest 15x40 GH, just so I don't confuse you. The 15x40 is the Quonset type that todate does not have roll-up sides. I would have to say that the double plastic layer is the best move especially in the FL heat. I planned at each additional GH construction to do that but I couldn't make a decision of the type of film to purchase. So far I've only used plastic film that I purchased at auctions. There are some radically new plastics available but they are expensive.

To answer your second question. Yes, I have the inflation fan running all the time. I think it is a key reason why that plastic has lasted all these years. But it will not only insulate in growing season, it will baloon-up the house so snow will slide off better. You shouldn't have that problem.

I have a few older pictures at my website(haven't updated in a year) and I have a few newer GH pictures but I have them scattered around. You can check out what I have at www.moserproduce.com and I will try to get some of the newer ones uploaded in the next month once things slow down a little.

You have a great website - I bookmarked it :)

Is there an online source you could recommend for the roll-up pipe? Can it be rolled up by one person? (My greenhouse will also be 40 ft. long.)

Do you monitor the air pressure between the layers?

Would Poly Patch patching tape be a viable alternative to heat seaming the ends of the roll-up plastic?

You have been a great help. Thank you.

Thank you for the compliment, Bonheur. The supplier of my rollup kit was PennState Seed Co. with offices in a few cities in PA but I thought they get their materials thru Paul Boers greenhouse supply. That website is www.paulboers.com . The rollup side can easily be done by one person if you get a kit, either with a hand crank or 18V cordless drill. Some people use an alternative method whereby they only have a "T" fitting at the end of their rollup pipe and they slide another pipe into it and then just 1.turn, 2.offset to clear ground with short end of pipe, 3.turn 4.offset.... and when the desired height is reached the long end of pipe rests on the ground to keet the side up. That system, although cheap, is difficult to work and dangerous.

I don't monitor air pressure between layers. You only need to look at the plastic and poke it with your finger- it should give readily under a little pressure,not like a fully blownup balloon. Like I said before, I'm using a bathroom ceiling fan. I have it setting on a crate and I have it 4-5" away from the plywood hole just blowing air toward it. That distance is how I control pressure. Sounds crude but it works.

I really don't think the tape would work well on the rollup ends although you might try it. They recommend a heat seal system that you crimp over both layers for a few seconds. I would think you could rent one. The time to seal the 4 corners of rollup sides must take 15-20 minutes. I'd ask around before buying a unit or attempt to try the kitchen gadget like Daisy Seal-A-Meal. But, after saying that, I don't know if I would worry about inflating the rollup sides. Heat rises and your greatest heat loss is likely in the upper section. Its a matter of choice.

We built our "hoop house" from discarded trampoline frames.

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Not a great picture, but if you are interested, I can take better ones in the daylight tomorrow. It was taken right about the time the snakes start to move in the evening here, and I am not brave enough to go past the pepper bushes at that time of night.

Anyway, we used 2 trampolines and a couple of toprail pipes from some chainlink fence for the frame. The in-between ribs are light gauge pvc, like what is used for sprinkler systems. We have built so many of these in the last couple of years, as it is practically free. It measures 24'Lx12'Wx 11'tall. I use greenhouse poly on it in the winter, shadecloth in the summer. It is a life saver.

Janie

What a great way to recycle trampoline frames! But where do you find them all?

I'd enjoy seeing more pictures.

How do you attach the poly & shadecloth to the frame?

How do you close in the ends for the winter?

We have been surprised at how many trampolines are discarded! You can check out FreeCycle if you have one in your area. We have a dump that takes metal, wood and tires, as well as household garbage, but you have to separate it. Or, maybe a little ad in the paper would be all you would need.

We cut the bent portions off the legs to leave straight parts to add to the arched sections to give the height we desire. Just slide them on, nothing else needed.

We used clamps like for hanging pipes to put it togeather. Across the bottom on either side, we used scrap 1x4's, to have a place to screw the pvc in place so it didn't walk off, and to attach with carriage bolts through the pipe, for added stability. We also used these 1x4's to staple the poly to the first year we used it, but we found that a length of PVC at least 2" in diameter is great for rolling the ends of the shade cloth and/or poly on works great. We have since gone to treated 1x4's, and my husband is going to add another run of 1x4 about 3' off the ground. He is going to install panels of fiberglass, so that I can slide them open and closed, for ventilation.

The ends are enclosed with PVC, 1" in diameter, bent to follow the shape of the arch. I use fittings to make cross pieces so I can hang a door. I think I have some old pics of that from last year. Every year it changes a little, as we decide what improvements to make.

The only thing we have bought for this project is the shade cloth, and the PVC for the ends and to roll the poly on. Oh, yes, and the poly.

When I say we have built so many of them, we have a lot of friends who are gardeners, and several are widows who want to supplement their income. They use these hoophouses to grow flats of plants for sale to the local nurseries. It has been great all the way around.

It is dark out, but I will get pics for you. Later, when it is not dark. LOL

Janie

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Hello, I was wondering if you could post your newer pictures here also? Thank you.

Tracy M.