Pergolas are good outdoor structures, but because of the lattice roof, they offer little cover from rain, sunlight and other weather elements. Adding a roof to a pergola is doable without too much difficulty. With so many options for a roof available, the most challenging part could be choosing the material that is best for the space and use.
Choose the material of the roof panels. A variety of options are available including PVC, wood, fiberglass and polycarbonate.
Measure the square footage of the pergola top. Purchase enough roof panels to cover the area.
Cut the panels to the pergola's length. Add 3 inches on the top and bottom to allow for a slight overhang.
Attach the panels one at a time using screws. Start on the left side and work your way across the roof. By doing so, it will ensure that the panels line up. The panels should overlap each other slightly.