I've been eying this greenhouse for about a year now. I priced the parts and material except for the greenhouse film at Lowe's back in July of this year. The costs was about $280 which included some extras for reinforcing and bracing. Our summer thunderstorms can get pretty rough and it would definitely be needed. If I remember correctly, the film would run about $40-60 including shipping. The width of this GH is fixed at 10' but the length could be as long as is needed.
At best I figured everything with openers and fan, it would run me about $450.00. Not too shabby for a 10' x 20' greenhouse. The site info states that the primary structure minus the film should last about 10 years.


http://www.i4at.org/surv/green.htm

This may end up being my 'starter' greenhouse.

The North Carolina design is very close to the one that I built this year. My differences are that the pipe clamps that hold the pvc in place are on the insides of the 2x6s that I used for the bottom frame. This allows me to secure the plastic to the top of the framing using lath wood and screws. Next year I might get some of the locking channel used on greenhouses, but the lath wood works pretty well.

I didn't sink any 4x4 feet as is shown in the diagram, but I did drive two 2x2 stakes per side to keep the ribs from bowing the frame out which it wants to do as the house lengthens.

Mine is 12x20 which I found places less stress on the pipe fittings at the top than when I tried making it just ten feet wide. I used ordinary schedule 40 pipe, ten feet long, and they are glued into the fittings, but the cross pieces that add stiffness between the ribs are not.

The plastic I used is simple 4mil builders plastic twenty feet wide which worked well at the twelve foot width giving me about seven feet of height more or less. Next year I'll go to six mil though I'm seriously considering finally ordering real greenhouse poly. The builders plastic is good for one fall and winter here in Florida and begins to crack about the beginning of the next summer.

Except for the end framing (the doors mostly) mine is a larger version of the 8x10 house I built last year. So long as tree branches don't blow through it or my kids poke a hole through the plastic (once!) it held up well for me.

Thus far the two 1,000 watt electric heaters I have out there have kept it sufficiently warm though our lowest temp since finishing it has only been twenty eight. I've already decided for next year I'm going to put an insulated pool cover on it. I'm at my limit on the amount of power I can get out there.

It's a good design if you won't be dealing with major temperature extremes. If you will I strongly suggest insulating it as best you can.

.....Alan.

Alan,

Hey that's some great info. I'll copy and paste that into my file along with the list and instructions for the house. Good to know it can go 12' wide too. I was really wanting one a little wider. Is it okay to ask you questions, if any comes up when I'm building?

We can hit some pretty wild extremes here in central SC.
I remember one winter quite a few years back we were near 0 deg. and we have maxed out at about 106 deg just this past year. There's always the errant hurricane (Hugo) that visits, and the wind blew about 7 weeks straight just this summer, with average gusts at 35 knots. I always keep an eye and ear out for our temperamental weather. I'm pretty sure I am going to go with regular greenhouse film just so I don't have to deal with it every year. I would really rather have the polycarbonate but...sigh.....the film will have to make do.

Well, I don't purport to be an authority on greenhouse building, but I'll answer what I can if you have questions.

In the case of really big wind such as a hurricane I figure to either put down ground anchors on both sides then tie the whole thing down with rope or take the plastic off. With no covering the wind resistance is minimal.

Without shade cloth or shade paint the house isn't very usable in the summertime. You could move it under tree cover I suppose. Mine is mostly for winter use.

.....Alan.

It will most definitely have a shade cloth and a couple of fans too.

I am pretty sure I can get by (winter) with a couple of oil heaters. These are the small electrical ones that look like a radiator. My boss is using 2 in her 25' X 30' greenhouse this winter and it has been very cozy every morning when I went in there, even when it was 22 degs.

I appreciate your willingness to ans. questions. Who knows, it may go easy as pie....(yeah right)!!

Alan if you do go with 6-mil greenhouse grade poly (Teflon coated poly) you can get up to 5 years use before you need to replace it. Greenhouse grade poly only has the Teflon coating on one side, so you need to be sure that the coated side is facing the outside. - Millet

Some follow up on the greenhouse that I built last winter using essentially the same design as is shown in the North Carolina diagram above.

The four-way fittings I built it from held-up fine in the winter, but once it started topping ninety every day I suppose the adhesive softened and they started coming apart. They're under a lot of stree when the hoops are made. Fortunately there are fittings with better geometries to be found so I'm going to retrofit with those.



This should elminate the stress problems and keep the bows from coming apart. They're about a dollar more apiece from Peaceful Valley Farm Supply than what I paid from my local Lowes for the regular three and four way fittings. I'm sure there are other vendors one can buy them from as well.

I've decided where I want the permanent greenhouse to go, but it's so far down the list of projects waiting for me to get around to them I have no idea when I'll be able to start it.

.....Alan.

I just bought a 20x40' metal frame greenhouse for $300 and the lady had a 40x100 that was $500 which if anyone has priced a greenhouse knows that is a great deal. I couldn't see me needing a 40x100' for what I was needing it for. If anyone is interested in the 40x100' I could give you the ladies number.

Thought I'd give everyone an update on this post.

This week I began construction on this greenhouse. I decided to make it 12 feet wide x 20 feet long. It has gone well so far, with one exception. I found it difficult to get sch. 80 PVC crosses anywhere. One place here local could order them for me for (get this now) $12.70 EACH!! Whoaaa! That's right.......nearly $120 for 9 sch.80 crosses. I told him to forget it. It's going to have sch. 40. on that one item. I just have to hope there's not a big learning experience waiting for me on this one. (I do by the way,have a well earned degree in the University Of Hard Knocks, but as things of that nature goes, I always seem to have one more 'class' to take. Ha ha)

I am waiting for the weekend when I can get family together to help hubby and me lift the PVC fitted purlin and ribs into the waiting clips. I'll try to remember to take photos to post later.

I AM so excited.

As usual I'm behind on getting ready for the season. I ordered the PVC fittings I show above from Peacful Valley and will be doing some minor retrofitting of my house. I only had one joint break and that's the one I'm going to use the new fittings on. They all held over the winter, but when the ninety degree weather came in that one joint popped. Using the new fitting will relieve the stress.

Still haven't bought proper greenhouse plastic so I'll wing it with the 6-mil poly I've already got.

My only problem now is to find another small fan to replace my old one that is falling apart. It's just a little eight inch fan but they're seasonal in nature so it seems every store in the area has stopped selling them for the year!

.....Alan.

My greenhouse is finally finished and loaded with my plants to be over-wintered. Here is a couple of pics, not the best of quality....sorry.

I am pleased with how it turned out. I did make a few changes. The main change was instead of building the door per the plan, I went to a thrift store and bought a used storm door and installed it. I can easily open a section of the door for ventilation. I had to re-screen it but that was easy as pie.

Another change was that I decided to use a few metal braces on the wood framework. That part of the structure seemed too wobbly since there was nothing to frame it up to (not my words, my husband's). With the braces it is now sturdy and stays in place.
I had it wired up with a 240 volt receptacle for the heater and several wall outlets for lights, fans and propagation mats. The materials cost almost half as much as the cost of the whole greenhouse! A friend installed it without any charge for his services. Thank goodness for good friends!

One other change was that instead of tacking the film along the long sides of the house, I tacked the film to furring strips and then rolled it under to finish tightening it up and then secured it to the ends. On the hotter days, I can un-secure the furring strips and roll up the film to allow a flow of air into the house. It is much like the large greenhouses that has roll up sides using an electrical motor except I have to manually roll mine up. Works for me.

I finally got around to making a few more pictures of the greenhouse.

I find that I 'm really liking this house even though I have practically outgrown it within the first month. So far it is easy to keep warm, but I haven't had any frigid weather to test how it does during those times.

Full lengh view taken early AM Friday morning.


View of entrance door:


Inside shots:

Main heater...a little over 19,000 BTU's.


Additional heat, if needed.....electric oil heater.


Office area....(LOL...) if you're wondering why they're on
skids....well, you've never sat in a chair in beach-like sand!!



The large red heater's thermostat had a ten degree range between low and high.
I didn't like this much heat drop and so had a friend install a thermostat that keeps it within a 4-5 degree range. Works very nice...


Citrus and other vegetation:

Sanbokan, Owari, Croxton, Juanita, Ponderosa, Parson Brown, and Meiwa (from Stan)


Ten Swingle awaiting grafts


Flying Dragons awaiting grafts


Flying Dragon roostock grafted onto (11/04) various stock from Scott K.


Variegated Citron budding out on Flying Dragon in 3 1/2 wks.


This is one of two dwarf Namwah bananas from Ned


I also have a Raja Puri banana from Stan.
Other plants growing inside include:
Duranta, Alocasia Esculenta, angel wing begonias, Kimberly Queen ferns, Asparagus fern, Hibiscus, gardenia, Pineapple Guava, 2 varieties of rosemary, basil, brugmansia, ornamental potato vines, airplane plants, 3 taichang lemon seedlings, Hirado Butan, calamondin, meyer, miho, variegated citron, ponkan, Buddha's Hand, ponderosa, and a couple other citrus cuttings I can't think of, that have been rooting for about 4 weeks now.

That's it for now.

Very nice. I love the chairs! Barbara

Question for A.T. Hagan
Just wondering about the adhesive failing in the hot weather etc
Was that the pvc pipe adhesive normaly used for plumbing work ?

Yes it was. I don't know why that one joint failed twice when none of the others on the house have yet.

I have been badly slack about my greenhouse this year. The whole year has been off for me so it was only more of the same. Yesteday I finally recovered the whole thing. Had to, it was supposed to go to 28 last night! Of course having spent all day out in the wind getting the work done it only went to 38...

This year I'm using the 6 mill builder's poly that I bought last year. It's not as translucent so I'm a bit concerned about getting enough light, but I say that every year when I put the new plastic on.

Of course I am paying the price for my laziness in getting my act together in that I have to shopping for another fan tonight as my old one is DOA. I may pick up another oil filled heater as well. So long as there is a fan to move the air inside those things work well without the fire hazard of the other types that I've used.

I've pretty well laid out in my mind where the permanent greenhouse is going to go and may start working on it next year. Same basic design as we've been talking about here, but using chain link fence top rail for the hoops.

Citrusgalore,

I like your photos! Nice house. Especially having the hard wired 240 power. I have to be careful not to overload my circuit.

.....Alan.