Big lean-to greenhouse: build or buy?

16 years ago

I need a 10x25 ft. leanto greenhouse for growing perennials and wildflowers. I don't need heat in the winter, but it needs to be cool in summer. I will be attaching it to the east side of an existing garage, so it gets morning sun only. For convection, I want manually operated vents on the roof and the long wall. I don't need automatic vents. I prefer polycarbonate to glass. I need a floor that can be cleaned easily, like a concrete slab. I don't need to pinch every penny, but I have no interest in luxury features; this will be a no-nonsense working greenhouse. Location is western Washington state, so we don't get extreme temperatures or high winds, but we can get several inches of snow.

I would build this myself with a wood frame, but I don't know how to build the roof vents so that they are rainproof. Does anyone know where I can get plans? I can buy a kit, and there are lots of companies that make them, but how do I find out which ones are good and have good instruction manuals? I'm not a pro builder, but I'm a pretty good amateur. What would you suggest? Thanks.

Sort by:Oldest

Comments (4)

birdwidow
16 years ago
For your use, and design, the easiest solution might be crank out, awning style, vinyl framed thermopane basement windows.

They come with screens and cranks, and are both sturdy, and innexpensive. They also seal perfectly when closed and because of the awning style, with the outer lip, if mounted on sloped roof, keep out rain even when opened.

I know this because we were looking for a means to bring more natural light into our small hen house and add a passive means of exhausting warm air, and after looking at expensive skylights, realized that the basemwnt windows would work as well, and they do.

We had to add additinal headers, because the roof rafters in the bulding are on 2 ft. centers and the windows are wider, but with new construction, that isn't an issue.
lilydude
Original Author
16 years ago
Birdwidow, can you tell me who makes the crank-out basement windows, or where to find them? Thanks.
Related Discussions
Lean-to greenhouse siding
Q
Comments (2)
dukes: i agree with scryn, the moisture shouldn't be much of an issue for your shop which appears to have a good moisture barrier with all the insulation on your shop. Whether you build a greenhouse from scratch or buy a kit is purely preference. I built mine from scratch with stanless steel angle-iron and unistrut for support. It's extra sturdy and i just bolted poly-c corrugated panels for the glazing. It cost just as much as a pre-fab but, i can expand it if i wanted to. I thought it would be more work to expand a pre-fab only because of matching materials and i worried about the weight difference and all that. Those on this forum with the greenhouse kits may tell you differently, especially the handier guys and gals. Again it is purely preference, but i enjoyed making the plans and building it against the house. Changes on the fly seemed simple enough to complete during construction. You can check out "My Page" for my blog on my greenhouse. I don't have any closeups of the structure support but i will eventually add that to my pictures. Good luck with what you decide to do. It'll be fun contructing it either way you choose!! Steve
...See More
Is this inexpensive Big Lots greenhouse worth buying?
Q
Comments (32)
I bought my Village Green- Deluxe Walk-in Greenhouse- "12 sturdy shelves for pots and seed trays" at the Big Lots in Santa Ana, CA (USA) Exact Address: 3321 S Bristol St Santa Ana, CA 92704 when they had all their Summer products on sale for 80% off. It came out to only $12! (Originally $119). If it turns out to be amazing or Eh, either way, $12 is an amazing deal! Can't beat that! I was surprised they had so many left! :) Right now Kohl's has the exact same one one sale for $119.69 (Originally: $126). There isn't a better feeling in the world than finding a GREAT deal and then seeing it being sold online for an outrageous price! :)
...See More
Building My Dream Greenhouse
Q
Comments (4)
I wish I could say I was finished. But unfortunately it's not. We have had rain literally every weekend the last 6 weeks and they're calling for it again this weekend. During the week it's dark before I get home. Now, I've torn up my shoulder carrying the roof panels. It's so close, but not quite there. Here are some pictures: This is a picture from the front corner of the greenhouse. The poly is up except for the corner side piece which is done, just not installed. The two corners are hinged so I can open them for ventilation or take them off in the summer. This is a view from the side of the greenhouse. You can see the ventilation holes at the top. They're each 22.5" x 30". I'm building a frame to cover them out of pvc molding 1.5x1.5. The poly will sit in a channel. Going to buy auto vent openers after I get the first one built and check the weight. A friend with a brake is going to install the tin to waterproof the area around the vents. The poly here is 5/8" x 10' x 48". I've pulled something in the rotator cuff on my left shoulder carrying these by myself. They didn't seem that heavy, just awkward. Pain didn't start until the middle of the next night. Next week I'll be going to the orthopedist. The back is framed in. You can see there's a big mess back here and I have to finish painting the building. Also, planning on building a brick patio out back. You can see the hinges on the one panel. I'm going to replace these with some hinges I found at Tractor Supply that will let me take the panel off in the summer. Here's the 450 gallon tank for the aquaponics setup. I have the Hawaiian Gold tilapia inside the house right now. I'm hoping to be completely finished by mid to late January.
...See More
Attached lean-to greenhouse cooling
Q
Comments (4)
I'm still trying to wrap my mind around how the g'house is set up. If you can't reach the side vents, and the top vent isn't operable, is outside air coming in through any opening? It needs to be intaking. You won't get much cooling if your fans are just circulating inside air around. Even when I don't have fans running, with the louvers slaved to them, I have manual vents I can drop. Sometimes I use them for passive ventilation when I don't want the big fans sucking air over my plants, like when it's a bright, but cold day in mid-winter. I can't see how you could even work in an unvented g'house in summer in Texas. Whoa. Your cheapest and easiest option would be to fix the ridge vent, and move the benching enough to access the side vent. My wind fans are all different sizes, and the big selling house has dual fans and all my houses have venting for air intake clear across the back. You can't compare your g'house to mine for fan sizes. You can calculate the rating of the fan you need by figuring out the volume of air in the g'house in cubic feet, and then find a fan rated to move that in a minute and a half. Then you need to calculate how large an opening on the opposite side of the g'house you'll need for air intake. If it's not large enough, your fans will not work to capacity and you can burn them up.
...See More
birdwidow
16 years ago
Vinyl framed basement windows, both crank out and sliders are sold in the Door and Window dept. at just about any large home center. Many mfg.- whatever brand any given big box chain happens to carry. They are all pretty much alike.

Actually, I'm wondering why you want polycarb, when for close to the same end cost, you could have all vinyl framed thermoglass and end up with a GH that would last if not forever, then at least a lifetime, and be easier and cheaper to heat or keep cool.
lilydude
Original Author
16 years ago
I have a big (30x30 ft) carport that I don't need. The roof is framed with sturdy prefab trusses spaced a few feet apart. What if I wall off the east-facing side, remove the corrugated metal roof and T-111 wall panels, and replace with polycarbonate panels? Would the structural rigidity be compromised by the loss of the metal and wood panels? If so, could I compensate by adding some wood diagonals to the frame? I don't think the wood trusses will decay, since my greenhouse will not be heated, and will be very well ventilated. Wood rot is not a problem at all in my present greenhouse, which I built 19 years ago.

This idea is very attractive to me, since I would end up with a 15x30 ft. greenhouse for the cost of the polycarbonate panels plus the vents and some kind of vent opening mechanism. The carport already has a concrete floor. Has anyone tried something like this?

Big lean-to greenhouse: build or buy?

Comments (4)

birdwidow

lilydude
Original Author

Related Discussions

birdwidow

lilydude
Original Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Big lean-to greenhouse: build or buy?

Comments (4)

birdwidow

lilydudeOriginal Author

Related Discussions

birdwidow

lilydudeOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

lilydude
Original Author

lilydude
Original Author