How to Build a Deck Cover Over an Existing Wooden Deck

Choose the height the cover will stand above your deck. Add the height of the deck to this measurement. Add another foot in length to find the length of your front support posts. Cut two lengths of 2-by-4 to this length using the circular saw. Add another 4 inches to this length to find the length of the rear support posts. Cut two lengths of 2-by-4 to this new length.

Dig a 1-foot-deep hole by each corner of the deck, using the shovel. Plant the front support posts in the holes at the front corners of the deck. Plant the rear support posts in the remaining two holes. Mix a batch of concrete using three parts sand, one part cement and one part water. Fill each hole with cement.

Measure the length and width of the deck using the tape measure. Cut two pieces of 2-by-4 to the length of the deck and two pieces of 2-by-4 to the width of the deck. Fasten the width pieces to the length pieces, using a drill and lag bolts, to form a rectangular frame with the same area as the deck.

Measure and cut sheets of plywood to fit the width of the rectangular frame. Nail the plywood sheets to one open face on the rectangular frame to form the roof of the deck cover, using a hammer and 1/2-inch galvanized nails. Varnish the roof using exterior-grade varnish and a paintbrush.

Set up a step ladder on the deck by one of the cover support posts. Raise the deck cover to the top of the support posts. Fasten the rectangular frame to the top of the support posts using lag bolts and a drill. You will need assistance to hold the roof up while you do this. Once the roof is bolted in place, varnish the support posts with exterior-grade varnish and a paintbrush.