I use the clear corrugated stuff (I presume you mean the stuff for roofs and whatnot), with an extra layer of clear film an inch behind it.

Supposely difusing the light is better for plant growth, but perhaps that is better done in the film behind. Using the milky clear polyethylene film is probably a good choice, being cheap and suitable to work with PC. Being behind the Polycarbonate means you can use the cheapest stuff you can get (no UV stabiliser, thin). I use PVC film, which also blocks IR (according to karenrei).

Having two layers is very useful to control dripping, which will otherwise encourage disease. Also, you will lose a lot of heat to condensation otherwise.

Finally, I found it quite hard to seal well. You can buy foam inserts - use them!

Are there any sites with photos? I'm having trouble picturing this stuff. I'm assuming you aren't talking about the same stuff used in the GH walls in kits like the HFGH ?

MollyD

Some of the suppliers on internet show photos of the corrugated style. Sundance has pictures at https://www.sundancesupply.com/index2.html. Use the left index to expand to corrugated, and then click on Greca pattern.

This place sells corrugated for commercial and has many photos. http://www.jaderloon.com/greenhouses/corrugated-polycarbonate-.htm

My local hardware store sells the corrugated, but canÂt find twin wall flat in less than 200 miles.

Can you let us know what city you are in or near?

I'm in Northern Calif, Mendocino Co. I have quotes from FarmTek, Sundance, and Tap Plastic.

Thanks Kittyl. I'm currently using film on my hoophouse but would like to upgrade that to polycarb next year. This looks like it would do the job but the $750. minimum order of the first place you list would be prohibitive. I do like the way they can flex around a curve. How much insulation do they provide?

Thanks!
MollyD

Sundance has an on line quote system. Crating was another $156 and shipping was another $330, and I wasn't quite yet to the $750 order. Two other out of state quotes had about the same shipping and crating costs.

I've had greenhouses made of several types of material. The corrugated polycarbonate may work for your area, but it will get quite hot and not provide much insulation at all. The double walled polycarbonate is much more expensive, but will provide insulation and will diffuse the light a bit more. The material I like the best is Solexx. It's double walled so you can seal the flutes and get very good insulation. It also diffused the light well. I have a greenhouse kit, but I'm going to buy just the material to cover a custom structure this spring.

I got mine from the Greenhouse Catalog. There are several thicknesses, but I have the 3.5mm.

http://www.greenhousecatalog.com/covering-solexx-panels-c-31_52.html

i recently purchased a quantity of clear c.p. at a local homecenter chain called menard's (i have no idea if they exist outside of indiana)...i've had good luck with it in the past, but i agree with the previous comments regarding condensation..poly film under it helps alot, but getting things sealed up often results in a less that pretty end result....luckily, i'm all about the plants rather than the looks, so it doesn't bother me much....c.p. is cheap, and will last you for a while, so if you're like me, and just looking to get growing on a budget, it's a good choice...

good growing, and many blessings to you and yours,

doug

I have now chosen and purchased corrugated because the cost was half the twin wall. Actually, IÂm quite pleased with how it looks going up. IÂm using clear, for the 6 fall/winter months, I want all the sun I can get. IÂm assuming IÂll need shade cloth in the summer. Yes, it gets hot here in the summer. The instructions say to not place the PC directly on dark beams where the heat will be over 125, or to paint the beam tops white. So the waffle board cross/beams going in were painted white, and the foam waffle end beam inserts are white. Yeah, that looked interesting, but I still think it looks ok. I have to figure out another foam insert along the outside edges of the PC, because of the way the factory says to install, but IÂll probably paint that to match my nice looking stained 2x4s.
The day I was in my hardware store I barely beat another customer buying more corrugated then I got, for a back patio. Apparently itÂs gaining popularity. IÂm leaning toward putting vents on the GH ends as apposed to either roof side. IÂve got an attic fan ready to put in with a thermostat. ItÂs beginning to frost here, IÂd better hurry if I want to get a few plants in there for protection!

I've been to Jaderloon in Columbia, SC. They are great to
work with and I plan to buy parts from them. I'm building my own greenhouse, but using their parts

Just a couple references for PVC's IR absorbancy:

http://www.addcomp.com/features/archive/janfeb05/janfeb05.htm
http://cals.arizona.edu/ceac/research/archive/HortGlazing.pdf
http://ag.arizona.edu/hydroponictomatoes/houses.htm

PVC isn't *great*, but it's much better than PE. One thing that I'm interested in is that I recently ran into a paper that stated that mylar and kapton films block IR as well as polycarbonate and acrylic. I'm interested in trying them out.