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How to cover PVC frame

Posted by jessicavanderhoff 7 Md (My Page) on
Sat, Feb 27, 10 at 16:28

I have this PVC frame:
http://www.cmcpwe.com/greenhouse/index.html

Last year I tried covering it with a big piece of the 4 mil clear plastic (just threw it over the roof and tucked it under at the bottom) but it shredded in short order. I'm thinking this was because there was a lot of extra plastic flopping around, which caught the wind.

I am wondering if anyone can tell me a better way. I'm thinking I need to cut panels for each face of the frame, but I am not sure how to secure them to the frame. Should I just use nuts and bolts through the plastic and through the pipe?

Any advice much appreciated.
Jess


Follow-Up Postings:

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RE: How to cover PVC frame

just a poor design. you need to wrap the peak with cloth or something to protect it from the points. gardeners supply has plastic clips that go around the plastic sheating and the pvc. take some 1x4 pine and sandwich the sheating between the deck and 1x4 and screw it to the deck.


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RE: How to cover PVC frame

Use 6 mil greenhouse plastic. 4 mil builders plastic won't last a single season. Add a ridge beam of some sort to spread the load and keep the weight of the plastic (and wind and rain) from pulling the end frames in toward the middle. This could be just a piece of wood strapping on either side of the frame peaks.

Dan


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RE: How to cover PVC frame

Jess,

I wood replace those sharp gable rafters with a one piece hoop. Maybe a 10ft length. You will lose a little in height.

Photobucket

I see other issues, but thats a start.

Eric


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RE: How to cover PVC frame

Second the poor design and the too-sharp peak, and the cheap plastic. Use greenhouse film and soften the peak and figure out a way to make the plastic taut - clips would be a good start. Make your own clips out of black poly irrigation pipe, cut 1.5" lengths, then cut lengthwise and take out ~20% of the radius. You'll need a purlin or ridge member across the top and maybe something on the roof sides to hold weight.

Dan


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RE: How to cover PVC frame

Even GH film will disintagrate where it touches PVC within a year unless the PVC is painted. I have first hand pictures to show it. I would suggest that you just accept that anything of PVC is short lived.


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RE: How to cover PVC frame

Thank you all so much for responding.

Terrybull, can you link to the clips? For some reason, I couldn't find them.

Eric, I'm ok with losing height. I guess I can just buy some 3/4 inch PVC, bend it, and stick it in where the old rafters go into?

Dan, what size irritation tubing would I use to make my own clips?

Bmoser, I understand that. The plastic tore within a few weeks and the greenhouse was unusable. I'm trying to find a cover that will stay put for a couple of months, so that I can actually use the thing.

Everyone is still recommending using a big piece of greenhouse plastic rather than cutting panels, right?


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RE: How to cover PVC frame

Bmoser: I would like to see your pictures of PVC degrading the plastic. I have 4 PVC and Metal high tunnel frames and I do not see any degrading.

Just curious,

Jay


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RE: How to cover PVC frame

Jessica, you would use the same size tubing as the PVC pipe. Black poly pipe is ubiquitous and not too expensive.


Dan


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RE: How to cover PVC frame

Jess,

Yes, You may have to play around with length. Put the PVC in one fitting and flex into the opposite fitting. Cheap and easy fix. A roll of white duct tape will cover the PVC / greenhouse plastic concern.

Eric


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RE: How to cover PVC frame

Sounds good, thanks everyone.

I will only be using it for a few months at the most. The rest of the time, it will be broken down and stored in a shed, out of the weather. I am fine with putting a new piece of plastic on every year. I'm just trying to make it last through those few months.


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RE: How to cover PVC frame

sorry, the clips are from territorial seed co.in oregon.


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RE: How to cover PVC frame

Jay, I'll just insert this one for now. It takes forever for me to upload a picture with a dialup connection.


PVC contact film failure


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RE: How to cover PVC frame

I should mention that in the picture I had lowered the PVC tubing since it only housed electric wires and had no structural significance. Just coming into contact because if inflating the inner layer downward caused the reaction that ruined the entire 96 foot length of new plastic film. All that I can use it for now is to replace roll-up sides.


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RE: How to cover PVC frame

Thank you for the picture. I appreciate you showing me that. I guess I don't understand why you had a problem, and others (myself included) haven't. I use PVC as my structural tubes and I haven't seen anything like that. I have replaced some of the PVC pipes with metal ones, but I am only replacing 1/4 of them. I will see how much stronger the building is with those and then I will see about adding more next year.

Thanks again.

Jay


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RE: How to cover PVC frame

I've read a lot about problems with poly and pvc. I used 10m woven poly over 1/2" pvc for 6 years without any such issues :shrug: guess it's true, YMMV...


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RE: How to cover PVC frame

I'm also wondering whether anyone has a suggestion of where to get a good price on greenhouse film, and how to create a door (can I sew on a zipper?)

Jess


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RE: How to cover PVC frame

growerssupply.com has some of the best prices (combined with shipping) IMHO; I'd get the IR and anti-condensate film (#109093), double it for cold evenings, and use the extra for a cold frame. I bet some craft store like Michaels has a consumer product to attach zippers.

Dan


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RE: How to cover PVC frame

Thanks, Dan.

Has anyone actually tried making a greenhouse with hoop rafters? The frame cracked in half from the pressure, and I can't figure out how to do this.


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RE: How to cover PVC frame

I experienced a similar problem in my small hoop house. I have a 6'x20' tunnel made from pvc pipes, with 6mil plastic sheeting draped over it. Last fall I anchored the 6mil plastic to 4- 1x4 boards with lots and lots of staples. It held up just fine until we had a day of 40mph wind, and it tore the plastic right off the boards! This year I used the same system with the same plastic sheet, except before I stapled the plastic back onto the boards, I reinforced the edges with extra strong Gorilla brand tape...it's like duct tape but rated for outdoor use. I attached one layer of the tape to each side of the plastic along both the edges that were to be secured to the wood, so it made like a plastic sandwich- plastic in the middle, tape on both sides. Then the staple had three layers to hold onto, instead of just one. So far this has held up nicely. It has only been in place for two months now, but we have had several days with 45mph winds and so far so good. One thing I will say is I wish I had purchased heavier wood to anchor it.


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RE: How to cover PVC frame

Good to know. I ended up rebuilding the top so it's basically just a big square with no roof at all, but I haven't figured out a cover yet.


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RE: How to cover PVC frame

I was also looking for a zipper for a hoop house. I found the product in the link below several places. AceHardware has it for around $12 but this outlet is cheaper (didn't check on the shipping cost).

Here is a link that might be useful: Zipper Door


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RE: How to cover PVC frame

Looks perfect-- thanks!


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RE: How to cover PVC frame

I've always used 6mil plastic sheeting from either one of the big home improvement stores. At the same store I bought the cheapest plastic clamps they sold (look for the bundled package with multiple sizes in it, they're cheaper that way) and clamped the plastic sheeting to the pvc pipe on the outside of each corner. There is no need to pull the sheeting super tight, its going to stretch anyway - you'll be tightening it all season long.

I also use the zippers to make a door in the plastic sheeting - they are over in the tarp supply section of the same store or at any hardware store. They have a peel and stick back but you need to reinforce the seam with all-weather duct tape because they won't last all season without help.

You have to add support to the roof, the one in the picture isn't designed to support anything. A flat roof isn't going to work either. One night of rain and it will collapse the plastic. You can add hoops of pvc pipe to the structure by using the heaviest pipe you can bend (you want a strong roof) and sliding them into place and securing them with zip ties - the kind used for bundling electric wires, also at the home improvement store.

You want your plastic covering to extend past the bottom edge. Use bricks or bales of hay to hold it down. If the wind gets under the seam it will pull up your greenhouse and toss it around.

been there, done that.


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