The high tunnel or hoop house is a popular greenhouse design for beginning gardeners or commercial production because it is easy to put together and materials are inexpensive. But a hoop house made of polyvinyl plastic and PVC pipe is only supposed to last for a few seasons. As a hoop house ages, it begins to show signs of wear. PVC ribs can crack and break and the polyvinyl skin can break. Additionally, a greenhouse can become completely smashed after a major winter or spring storm. Fortunately, restoring a greenhouse is even simpler than building one.
Pull the staples from your greenhouse plastic cover using a screw driver. Remove the cover from your greenhouse and assess its condition. If you've used cheap construction plastic for your greenhouse prior to this, you may wish to replace it with polyvinyl greenhouse plastic. Greenhouse plastic is longer lasting.
Repair tears in your plastic by cutting two pieces of greenhouse plastic that are slightly larger than your tear. Cover one side of each piece of plastic with double-sided polyvinyl greenhouse patching tape. Lay the tape in strips side by side. Do not let the tape pieces overlap.
Scrub clean your greenhouse plastic around the tear with warm soapy water.
Remove the backing on the tape on one patch and press it over the tear to patch the tear. Work all air bubbles out of the patch. Flip the greenhouse plastic over and stick the second patch to the other side of the tear.
Remove broken PVC ribs from your greenhouse and replace them with Gray PVC conduit pipe.
Stretch a wire across the top of the arch between your greenhouse ribs to create a ridge. Wrap the wire for one turn around each greenhouse rib to secure it in place. This will increase the stability of your greenhouse.
Paint the surface of your PVC ribs with paint to increase their UV resistance. UV can cause PVC pipes to become more brittle over time.
Stretch the greenhouse plastic back over the surface of the greenhouse and staple it back in place at the base.