How to Convert a Deck Into a Sunroom

Check the foundation of the deck first and make necessary repairs if the deck is concrete. Insulate the underside of a wooden deck if the crawlspace is accessible. Otherwise seal the top of the deck flooring with 1/2-inch plywood nailed into place and covered by indoor-outdoor carpeting. Cut the plywood and carpeting to fit flush with the perimeter of the room. Add caulking and wood trim around the edges of the floor to help seal out outside air.

Frame the sunroom to have glass panels around the walls. Plan to build in the bottom of each wall 24-inches high with solid materials. Design the room to have walls of windows two feet off the floor all the way to the ceiling. Use 2-by-6-inch boards to create wall framing with studs on 16-inch centers and openings for windows. Remove existing columns as the framing absorbs the roof's weight. Nail exterior siding on the bottom 24 inches of the deck to be fully enclosed.

Construct the frame for the roof with two-by-fours or two-by-sixes. Cover with plywood and add shingling. Connect the roof frame to the frame of the wall with brackets. .

Insulate and finish the interior of the lower wall sections. Staple roll-type fiberglass insulation between studs on lower walls. Run electrical wiring throughout the room in the bottom 24 inches to be solidly enclosed. Install electrical outlets before covering those sections of the walls with drywall. Use joint compound to finish the drywall before painting.

Install windows for the sun room. Square up wall framing to receive glass panels or premade windows. Use a carpenter's square to ensure 90-degree angles in all corners for windows. Add shims of wood under finished boards to precisely form frames to support glass panels or windows. Use two or three workers to lift the windows into place. Attach windows into frames using an electric screwdriver. Caulk around all window perimeter areas, both inside the room and outside.

Add finishing touches. Install a premade walk-out door for the sunroom. Secure to framework with three-inch stainless-steel screws. Make sure opening and closing the door will not jar nearby windows. Replace an interior door leading into the sunroom from inside the house, if needed. Consider adding a door with glass panels to give added light to the home's interior. Install electric lights overhead and ceiling fans if desired.