How to attach film on ends of hoop house
Printer-friendly versionI need help constructing the ends of my first cold frame. I have 5'x10' raised beds built from 2x12s. I attached 1-foot segments of 1" PVC pipe along the sides of the 2x12s (on outside) into which I inserted 10-foot lengths of 1/2" PVC pipe for the hoops. I will brace the hoops with one or two 10-foot lengths of 1/2" PVC pipe, probably attaching them with zip ties or something similar where they intersect the hoops. I planning to cover the structure with plastic 6 mil plastic film (if it isn't too heavy for my hoops), secured with pipe clips as necessary, and stapled to a 10-foot length of wood or strapping (maybe 1x1s) at each side. I should be able to roll up the sides when the weather permits and when I need access to the plants and the bed.
If all this works, what I need help with is a convenient way to cover the ends, which are pretty nearly semi-circles. I could make the plastic long enough to flap and fold at each end, but that seems like a nuisance every time I open and close the cold frame, unless there is a way to lock the folds in place easily. I was also thinking of making two detached ends, each with a 10' hoop and a 5' straight bottom pipe to match the curve of the main structure, and attach a neatly cut semi-circle of plastic film to each. Then I could theoretically set an end in place when I wanted the structure closed, and remove an end when it needed ventilation or I wanted to reach in. But how could I adequately seal the ends to the main structure?
I would appreciate any suggestions?
Most hoop setups I've seen are how you describe your first option. Just folding over the ends and wrestling with them when you want to uncover the sides. If you can build an end hoop to match (as you describe) you could run a deck screw thru the end hoop pcv into the end (hoop) of your 1/2 inch pcv hoop. I've seen several pvc houses constructed by this method (connecting the pvc together via deck screws). You need to make sure you use coated screws (for rust). What I've seen done is to use a screw thats a little long - so it sticks out a ways after being run in, and then grind the end off. You definately don't want to leave the pointed ends exposed - they will rip both the plastic and any skin that comes to close. You also will probably need to pre-drill the holes unless you have brand new pvc - if it's been out in the sun very long it will tend to split when you try to just drive the screw in (without pre-drilling). You could also use this method to hold your hoops to the bracing material. I've seen zip ties used - but they usually aren't uv resistant. This means that within a couple of years the ties will start breaking - might not be a problem if you don't intend to use it more than a season.
One other option - if your ends are facing north/south you could build the north end from plywood (or some other sold material). It probably wouldn't be as pretty but since the north end won't block any light it won't hurt - and it will add some strength to the structure.
Thank you both for your replies. I was making it too complicated. I think I will start simple (plain plastic with clips), but keep in mind the tips about the screws, especially for the bracing I may need.
Make the ends seperate pieces of plastic and use snap clamps to secure the roof and end wall poly around your PVC tubing. This is a pretty common way of constructing and end wall.
Here is the link for 1" snap clamps:
http://www.greenhousemegastore.com/Snap-Clamps/productinfo/SN-SC/