Corrugated plastic roof panels made from polycarbonates, acrylics or fiberglass provide protection from the elements while allowing light to filter through. The corrugation adds strength to the plastic, which typically comes with a green or white tint. Fiberglass chips more easily than the other materials. Polycarbonates are more resistant to hail damage. An outdoor shade constructed with corrugated plastic roof panels is more economical than a traditional patio cover.
Things You'll Need
- Measuring tape
- Post-hole digger
- Four 8-foot-long pieces of 4 by 4 pressure-treated lumber
- Plumb bob or spirit level
- Five pieces of 12-foot-long 2 by 4 lumber
- 2-inch deck screws
- Five sheets of 3-foot-wide corrugated plastic roofing, 12 feet long or longer
- Garden shears or jigsaw with a fine-toothed blade
- Roofing fasteners
- Silicon caulk and caulk gun
Drive stakes into the ground at the four corners of the outdoor shade. Builders typically use a string line for this purpose. Tie a long piece of twine to a stake. Measure the distance to the next corner of the shade area and drive a stake in that spot. Repeat the process for the other sides of the square or rectangle. Space the stakes 11 feet apart.
Dig 18-inch-deep holes at the stakes for the support posts. Tamp the bottom of the hole flat and set a post in the hole. Use a plumb bob or spirit level to check that the post is straight. Fill the hole with soil loosely and check the post again. Once the post is true, fill in the hole and tamp the dirt firmly into place. Tug on the post to ensure that it's secure. Repeat the process with the other three posts.
Use deck screws to attach a 2 by 4 to span the distance between the tops of two posts. Screw another 2 by 4 to the tops of the opposite posts. Complete the sides of the roof by screwing 2 by 4s to the tops of the posts, spanning the sides. Finish the roof framing with a 2 by 4 that spans the center of the roof, parallel to the sides.
Cut the corrugated plastic roofing to fit. Very thin plastic can be cut with garden shears. Higher-quality plastic may require a saw. When measuring the width of the plastic sheeting, keep in mind that each sheet will overlap the next by one ridge. Pre-drill the holes for the roof fasteners on every fourth rise on the corrugation. Make the holes slightly larger than the body of the screw so the plastic can expand and contract. Drill holes at both ends of each sheet; the plastic will be screwed into opposite 2 by 4s with the center of the plastic roof resting on the center piece of lumber.
Set two pieces of roofing next to each other. Run a bead of silicon caulk along the ridge of one of the sheets and overlap the next sheet so the caulk forms a seal between the two pieces. Repeat the process until all of the pieces are joined. Slide or hoist the roof into place on top of the frame and screw it into place.
Tips & Warnings
- Make a sloped roof by using shorter lumber on one side or by building up the roof along one of the rafters before attaching the corrugated plastic.
- Adjust the dimensions for a larger or smaller shelter. Add more framing for a larger shelter.
- Set the posts in concrete for a more permanent structure.
- Individual plastic roofing manufacturers may recommend different kinds of fasteners and caulk. Follow the manufacturer's installation instructions.
- Wear eye protection, a mask and goggles when cutting or drilling into the plastic.
- Check the building codes in your area to determine if corrugated plastic shelters are allowed.
- Use an 8/12 pitch for a roof in an area of heavy snowfall.