Most deck covers are made with flimsy canvas on weak tubing. While they're okay for the sunny calm days, on wet and windy days, they just don't hold up. The solution is to build a metal deck cover, that will be sturdy and solid in any weather, and at the same time offer you real protection from the wind, rain, snow and sun.
Trace a pattern of a 4 x 4 directly next to the corner post at the corner of your deck. You should use one of your 4 x 4s to get this pattern, and trace it clearly. The pencil marks will wear away or be covered later. Do this on each corner of the deck that is not adjacent to your house.
Cut out the squares for your 4 x 4s in the flooring of the deck. Use the jigsaw, and make sure that the holes are as neat as possible.
Insert the 10-foot 4 x 4s through the holes. They should be butted up against the corner post and will be between the first two deck joists.
Drill two ½-inch holes through the joists and the 4 x 4s. You may need a partner to hold the wood steady for you since it will not be anchored to anything at this time.
Anchor the 4 x 4. Insert the carriage bolts into the holes, thread on the lock washer and nut, and tighten down both with the adjustable wrench. You will do this with each corner post.
Create your framework for your cover. Calculating a 20 degree angle with your protractor, attach the treated 2 x 6 to the 4 x 4, run it to the building at the angle specified, and attach it there using 3-inch screws. Do this on each side so that you have a frame to attach your metal cover to.
Stabilize your frame. Use one 2 x 6 across the side of the building connecting both ends of the 20 degree mounted boards together. Secure that to the building as well as to the adjoining boards. Use the other 2 x 6 and attach it to the 4 x 4 support poles, for added strength and a stable frame for the roof panels.
Attach the metal cover. Lay out the metal roofing panels on the frame, and with roofing nails, secure them to the boards. The 20 degree slope will make sure that snow literally slides off during the winter, and the metal itself will last the lifetime of the building it's attached to.