Northern Greenhouse Sales Inc.
Attaching Poly to Metal-PVC Frame
How to Attach Poly to the Ends and Sides of a Metal Frame or a PVC Frame Greenhouse
Perhaps the most common question asked of us is how to attach the poly to the ends and sides of a PVC greenhouse or a metal greenhouse, whither the frame is metal tubing or rebar. On a wooden frame you can attach the poly with nails or screws and our flexible Cinchstrap or Polyfastener, or with wooden lath. You can't nail into metal or PVC. Screws can be used on all except rebar, but it's difficult. On rebar it's impossible. So what's the answer?
The short answer is "Attach wood to the metal", and then attach the poly to the wood!
Metal is used instead of "Metal or PVC" throughout this article to make it easier to read, but the same method can be used for PVC pipe as for metal. If you don't want to use screws to attach the poly to the PVC.
Before attaching the poly, you first have to attach the wood. Attaching the wood gives extra stability and a place to nail on the poly. Here are the details.
How to Attach the Wood to the Metal
Pipestrap, clasps/clamps, staples, u-shaped 2 pointed nails, nails hammered over into the wood on the other side
Clasps or clamps can be purchased to go around the pipe or rebar and into the wood. To save some money on clamps, I use some long nails and partly drive the nails into the wood and then tightly curl them by hammering around the metal pipe or rebar. Attaching wood to the metal at the two ends of the structure makes a permanent framework for fastening the poly to the ends.
The Long Sides - Attach Wood Along the Long Sides
Using the method described above, attach boards (outside of the frame), along the lower edges of the long sides of the greenhouse. This will give you a place to nail down the bottom edges of the long sides of the main piece of poly covering. But don't put on any poly yet!
Attach Wood Around the Metal Curve at Each End
To fasten poly to the ends of metal structures, I buy or find short pieces of wood, usually 2 to 3 feet long. I prefer two by fours. I attach the wood within the space formed by the curve of the metal, to follow the curve and to create something into which I can later drive nails to hold the poly.
Attaching Wood Along the Ground at Each End
Along the ground at each end I attach a preserved wood sill plate. Attach it to the ground by drilling holes in it every few feet and driving pieces of rebar rod into the ground to hold it down. Attach it to the metal frame by using u-shaped staples, clamps, or bent over nails, as above.
Making Vertical Studs at Each End
Secure wooden vertical studs to the ground plate and to the wood framework that follows the curve of the metal frame, as above. This wood at each end makes a permanent framework for building doors and vents at each end.
Making Doors And Vents at Each End
I build the doors and vents framework out of wood and cover them with poly. Build lots of vents please! Vents are good for your plants and also for your poly life. Neither plants nor poly like to get overheated to where they cook or wilt. I attach the poly using my Cinchstrap as a lath between the poly and the nail-head.
Cover The Structure with Woven Poly Covers
The sides and top can be covered with one big piece and the two ends can be covered with separate pieces of poly. Or, you can instead use one big piece of poly to cover the whole length and the ends in one go, which I find works well on a small greenhouse. Either way, fasten the poly to the wood you've attached as above.
Feel free to Email us with your questions. If you prefer to talk to Bob about it in person, the easiest way to catch him by phone is before the rush of calls that hit the midst of the business day. For easiest connection, try calling between 6:00AM and 10:00AM Central Time at 1-204-327-5540.
Have fun building your greenhouse!
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