Roof for a Green House

[oldmanriver]

Thanks to the recent ice storm that wipe out my carport I now have a nice metal building frame , Plans are to make a green house . I called around today to try and find some fiberglasss planels for the roof no luck there . Can I use heavy plastic on the roof or will the snow be a problem also I plan to heat it with wood will the sparks from the stove pipe burn holes in it . What do you have on the roof of yours ?

[postroad]

Use a woven poly for better results. If you have big bucks invest in double or triple wall polycarbonate sheets.

[Beeman]

Lowes has panels that would work, some made special for greenhouses.

[catahoula]

Farm-Tek has some pretty good prices on greenhouse supplies. We did the roof in the more expensive polycarb, and the walls in a more affordable vinyl.

They sell a fancy plastic that is good for a few years, it's not exactly cheap and it has to be replaced often. Visqueen would work and would be affordable but it's at the mercy of the elements, I don't think it would take a snowload. So, to just extend your season you could use less expensive materials.

What is the layout of you metal framing? You may or may not be able to find material to match your layout. You may also have to add additional support to qualify for the ten year warranty on the polycarbonate material.

The nice thing about the plastic covering (visqueen) you can roll up the sides for air exchange.

For the wood heat, I imagine if you have a screen over the stove pipe to catch sparks you should do okay. The polycarb is so expensive however I don't think I would risk damaging it. Maybe look into some sort of passive solar method to heat your greenhouse.

[Nomad]

Originally Posted by postroad

Use a woven poly for better results. If you have big bucks invest in double or triple wall polycarbonate sheets.

I had a hoop type greenhouse with some kind of rip stop translucent fabric for the sides and ends. But for some reason they made the walk in door out of double wall polycarbonate. Within one year...something...(the UV light maybe) made it so brittle that it eventually just disintegrated. Maybe I was just lucky, but I know I'd never use polycarbonate again unless it has been considerably improved.


Nomad

[Earthbound]

We have used these carports many times and still have 4 of them up . We used 6ml greenhouse plastic for the roof and walls and then attached them to the roof and sides with channel lock and wiggle wire. Easy to put up and as long as the structure itself is solid, your in good shape.
corry

[catahoula]

Originally Posted by Nomad

I had a hoop type greenhouse with some kind of rip stop translucent fabric for the sides and ends. But for some reason they made the walk in door out of double wall polycarbonate. Within one year...something...(the UV light maybe) made it so brittle that it eventually just disintegrated. Maybe I was just lucky, but I know I'd never use polycarbonate again unless it has been considerably improved.


Nomad

There are a few different makers of double wall polycarbonate, DuPont makes a good product. We have a little 8 X 8 green house glazed with a double wall polycarb that has pretty much suffered the same fate as your door. It has fogged up and started to crack along the edges, I'm pretty disappointed. Of course that is neither here nor there all the snow slid off the roof in one shot and literally wiped the whole thing out.

Our big greenhouse is glazed with the single wall corrugated style polycarbonate. It was quite a bit cheaper than the twin walled stuff with the same ten year warranty.

[Macybaby]

I used the best poly/fiberglass panels I could get locally. They are suppose to be both sun reisistant and decent for snow loads. It's call Super600.

I would have loved to go with the doulbe wall polycarbonate, but the shipping costs were way more than I could handle. I've converted the end of my garden shed to a greenhouse and it's almost done. I used double pane windows we pulled out of the house for the side walls and the poly panels for the roof. I also plan on putting up 6ml clear film on the inside of the roof. It will help with heat loss and keep condensation down. Sure hate getting dripped on while working in the greenhouse!

The worst part was getting the shed cleaned out last fall so I could work on it over the winter.


This was last week - took a warm day off work to get the roof part done.


Last Sunday I got the metal back up across the front.

Cathy

[postroad]

Rip stop woven poly or polycarbonate panals will disinigrate quickly in the sun if they do not contain some type of UV stabilizer.

I think there are some cheap products out there but the stuff I have used has lated up to seven years. I like my double wall polycarbonate because it has some insulation value. Something that is important here in Canada.

[shellyr44]

We used clear pvc panels that costs around $13 a piece. I'm sure they are called something else but we love them and they have stood up to heavy snow loads and wind and rain.

[kruizeag]

I've got a 10x20 greenhouse and 12x20 high tunnel both made from carport frames. The 10x20 greenhouse is 3 years old and has held up very well to high winds and hurricanes. They are both covered by 6mil greenhouse plastic. The greenhouse is double layered and inflated with a cheap $20 blower from an inflatable yard decoration. We don't get heavy snow here in central VA, but the water and light snow I've had runs right off. We heat it with a small wood stove. the pipe vents out the back and I put a 90 degree elbow on the top facing away from the greenhouse. No issues yet with sparks.

[kruizeag]

Oh ya, check out my thread under the gardening section of HT titled "High Tunnel for under $300". I have pics posted with it.

[Harry Chickpea]

Don't even think about using construction plastic, clear or "crystal" plastic. It'll last a few months at best. 6 mil greenhouse plastic has the UV stabilizers that keep it intact for supposedly 4 years. Ours has been up for a year and is in very good condition. If you use 6 mil, it will flex in the wind and shed some snow or water because of that. Shipping costs are high, so take that into account when pricing. A local place with a higher price could be cheaper than a deal a few states away.

[Wolf mom]

I'm taking a gardening class from a woman whose husband builds them.

He builds the roof 1/2 regular roof (the part attached to the North wall) and the other 1/2 is Lexon, a type of polycarbonate. That makes it somewhat cheaper. Also when you follow the sun, if it's all polycarbonate or whatever, heating really becomes an issue in the summer.

He uses the tripple layered Lexon for insulation as he builds passive solar greenhouses. I've seen pictures of their greenhouse with snow on the ground and lots of greens growing inside.

If you use any type of sheet plastic, make sure it's very tight as when it's loose, it'll rip in the wind.