polycarbonate or traditional film???

We're going to get the first of our greenhouses built this month, starting in a couple of weeks. I'm still back and forth on which way to go. Wondering if anyone has used the polycarbonate stuff that lowes sells? I've read mixed reviews on their site about it.

The walls are going to be traditional film over 2x4 studs to give room for double layers, just not sure about the roof, if I should make a hoop roof with film or a gable roof out of poly... I don't want to do the gable roof out of film because of possible snow loads stretching or tearing it and I don't want to waste the money and heat by making the roof pitch too steep in order to shed snow.


Advice? Opinions? This will not be a "tunnel" it will be an actual horticulture greenhouse for starting the plants for our market garden.


http://www.lowes.com/ProductDisplay?partNumber=77000-1115-1418C&langId=-1&storeId=10151&productId=3043807&catalogId=10051&cmRelshp=req&rel=nofollow&cId=PDIO1

this is a link to the polycarbonate I'm thinking about... anyone have suggestions of a better product? I don't have to put that on until next month, so I have some time...

I love the polycarbonate. It is easy to build with and very durable. I will never go back to film for any permanent greenhouse application. My greenhouse is 8 years old and the polycarbonate is in good condition. If I had it to do again, I would skip all the fancy clips and breathable tape, that is where the cost adds up. In a more humid environment though, they may be advisable. My polycarbonate has held up impeccably to high winds (50mph) and heavy snow loads (2+ feet). Like I said, I love the stuff, all the way.

One thing I have found is that the price on polycarbonate varies hugely between suppliers. If you can find a greenhouse wholesaler locally, you will likely see a savings of 100% or more. It is unbelievable how much places like Lowes or FarmTek charge for their polycarbonate. I use a company in Denver called Denver Wholesale, though you would likely need a more local source.

good luck!

M, I built mine out of poly. In this thread...

https://permies.com/t/6718/greenhouses/greenhouses

the third post down , I posted some pictures.

I hope they are still visable?

awesome! that was quick !!! thanks folks, I guess I have my answer! I love the heat sink you have on yours, that's very practical and pretty. Due to cost, I'll still be using film for the walls, but that's just to get us through this first year, guess I'll add it later.

thanks for the advice on shopping around, that seemed like a rather high price, and I have found some time spent browsing the web and driving with the truck and trailer tend to save us big bucks on some things. The locals have a 400% markup on the underlayment/weedproofing fabric we use, over a thousand bucks for a 15x300 roll of it, but I can buy it out of the factory 3 hours away for $250 per roll... I'll check around for sure. We'll have the structure built and the benches in it this month, that'll give us February to put the roof/skin on so we can start in march. Heating is no issue, will take me a few hours to install our spare outdoor wood furnace for it.

I had read some reviews about it becoming brittle and getting easily damaged, but then I read conflicting reviews stating how well it had done haha... anyhow, I'll shop around. If I can make myself stop and take pictures, I'll post them up and a budget as well!

Polycarb is nice, but not sure if it is worth the money. I still lose it to hail every 7-10 years as a roof. Mine is only a chicken coop, so it isn't $$$$ but I am going with regular film for the hoophouse. Two layers and a blower makes it TIGHT and it will handle a lot of weather.

this first one is gonna be on the small side, haven't ironed out all the details yet, but it'll be 12-16 ft wide by 30-40ft long. somewhere in that range...

I do really WANT to like the polycarbonate haha, now you come along and make me wonder again hehehe, thanks.

I'll probably just go with the flow here and see what I can come up with as things present themselves. Plans be damned, they never work out how I want them to anyhow, when I build by the seat of my pants I can usually bring things in cheaper anyhow.

I'll post up here as it goes and try to get some pics as well.

We used film for years, and are now using polycarbonate in some places. When price-shopping for polycarbonate or film, make sure it's UV-resistant. Our site gets very strong gusts of wind so the film does tear after just a few years; it also sometimes makes a roaring noise in the wind, which is irritating because the greenhouses are attached to our houses. Polycarbonate and glass are a lot quieter in wind. We do get some snow but because we always build so the greenhouse glazing is on an angle, the snow slides off. With film, you can go inside the greenhouse and punch upwards to jolt the snow off if it is sticking and making the film sag, but with polycarbonate I don't think it would be a problem.

Rebecca Norman wrote:We used film for years, and are now using polycarbonate in some places. When price-shopping for polycarbonate or film, make sure it's UV-resistant. Our site gets very strong gusts of wind so the film does tear after just a few years; it also sometimes makes a roaring noise in the wind, which is irritating because the greenhouses are attached to our houses. Polycarbonate and glass are a lot quieter in wind. We do get some snow but because we always build so the greenhouse glazing is on an angle, the snow slides off. With film, you can go inside the greenhouse and punch upwards to jolt the snow off if it is sticking and making the film sag, but with polycarbonate I don't think it would be a problem.

This made me laugh, because this winter I am dealing with my first greenhouse, built as a seasonal extension on my house and with a film skin. Been doing lots and lots of pushing stuff off the roof Next time, I work out a way of fitting the film more tightly and giving it some better support. Agree on the wind noise too.

That said, I just love having an attached greenhouse! Green space attached to my kitchen in the middle of winter with snow outside!

A great advantage for the film is that we keep the top attached to the house, but release the sides and bottom in spring, and roll them up under the eaves all summer, so we don't get overheating.

ok! so here we go! I'm making another post about the one we're building starting this weekend! quite excited

There are lots of great greenhouse glazings out there. Poly-carbonate is certainly a good choice but don't confuse the corrugated poly-carbonate you can buy at lowes for greenhouse poly-carbonate. While the chemical composition is the same, when it comes to performance they are VERY different products.

The corrugated poly-carbonate you can buy at lowes is one of the worst things (performance wise) that can be used for a greenhouse. The corrugations increase the surface area of the glazing, increasing the rate of heat loss for the structure. Additionally the corrugations reduce light transmission. So in terms of greenhouse performance (light transmission and heat loss) greenhouse film is much better than the corrugated poly-carbonate.

It is important for greenhouse film to be installed at the right temperature (to get the right amount of stretch in the film). So long as this is done there should be no problem with snow load on the film (so long as the framing holds up). In Montana I know of a greenhouse that has been in operation for 35 years using greenhouse film on a shallow roof pitch, (3:12) with no snow load problems.

Multi-walled greenhouse poly-carbonate on the other hand is a great product. The difference here is that the two walls give the glazing an insulation value. These products usually come with a lot of added expense of H-channel and U-trim. I distribute a product called Solexx, it is what I have found to be the best glazing for the price. It has great insulation value, good light transmission, good lifespan, and is a fraction the cost of comparable products. It is easy to install, with no need for the H-channels and U-Trim. It is also flexible enough to be installed on hoops.

4 mil plastic for me. A roll lasts for years, and EZ on/EZ off. Can cinch it up when the WX warms but is still "iffy." To each their own and best of luck to you!

Hi All; I went with solex covering on my greenhouse ! I LOVE IT !!! They sell this in rigid panels, but the way to buy it is in a 49.5" roll by the foot , they will ship over 100' free ! Its not cheap at 7.99 a foot but has a ten year warranty for uv and actually has an R value . This stuff folds around corners ,so no air gaps . It is opaque but the lighting is superb! As far as how tough is it ? Two montana winters with heavy snow ,sub zero , sleet , hail , wind , rain and it looks like the day I installed it! My green house is 12 x 20, 2x4 frame construction. I am 1/2 way thru my first winter with a rocket mass heater in the greenhouse and all i can say is EVERYBODY SHOULD HAVE ONE ,if they have wood available to burn. Currently temps are very moderate 25 at night and 35 during the day I burn the rocket for a few hours in the late morning and again in the early night then it stays out till 9 or so the next morning , greenhouse is 47-55 degrees in the morning !!! When temps were running at below zero at night and single digits during the day I would start the stove in the early morning (around 6 or so) and burn it full till noon or so let it go out for a few hours then relight in late afternoon keeping it going till 10 or so at night and the normal morning temp was 40-45 degrees !!! With NO FIRE all night !!! How cool is that !!! I do have a propane heater installed ,it is set as low as it can be and the only time i have seen it running was early morning on a below zero night that i slept in and did not get out to the greenhouse till almost 8 am !

I originally built our small green house using the polycarbonate corrugated panels. these were specifically marked as being suitable for green houses. what a load of crap!! within 2 years some had gone brown and started cracking. then when the next hail storm came through i ended up with plastic shards everywhere.
When i built the larger green house i used the Bi-wall polycarbonate panels. These were bought from Menards. and are 4x8 ft sheets. even during the winter we are well above freezing during the day if there is any sun, and it only takes a small heater to keep it above freezing during the night. there not cheap ($42 each)but worth it.

I also had a Polly tunnel that we used for a long time. i originally used plastic sheeting. these didnt last much over a year, i then bought reinforced plastic from USplastics. more expensive but it lasted for a long time with very few issues.

https://www.menards.com/main/building-materials/roofing/specialty-roofing/6mm-4-x-8-clear-polycarbonate-twinwall-roof-panel/1594351/p-1539153017945-c-5819.htm?tid=2309662961262105743&ipos=25

https://www.usplastic.com/catalog/item.aspx?itemid=26717&clickid=search

Regards Phil