Adding a metal roof to your carport is relatively easy even for novice do-it-yourselfers. Follow the steps below to install a metal roof on your carport.
Step 1: Remove Existing Roof Covering
Remove all shingles, tar paper or other roof coverings. Check the roof waterproofing. If the waterproofing is intact and your carport has no leaks, you can apply the new metal roof over it. If the waterproofing has tears or holes, remove it.
Step 2: Check the Roof Underlayment
If the roof underlayment is solid and intact, install a new layer of waterproofing felt according to instructions. If the roof underlayment has holes or the wood is warped, remove the damaged sections and install new roof underlayment, then add the waterproofing felt on top.
Step 3: Measure to Purchase Metal Roof Sheathing and Flashing
For an aluminum or sheet steel roof, you will need to get flashing made of the same metal to prevent chemical corrosion of the roof sheathing. Measure the size of your roof and determine the number of metal roof panels you will need. Have them cut to size by the manufacturer. Most panels are 3 feet wide and come in lengths from 5 to 40 feet. Measure carefully at the roof edge to order the correct rake flashing to finish the roof.
Step 4: Install the Roof Flashing at the House Wall
Install roof flashing so it overlaps the wall of your house and under the waterproofing by 6 inches. Make a tight seal between the flashing and the waterproof felt to prevent leaks.
Step 5: Lay Wood Strips to Support the Metal Roof
Place and nail 1 x 4 wood strips at a right angle from the wall to the edge of the carport roof. These support the metal roof and keep wood and metal screws from penetrating the carport ceiling.
Step 6: Install the Metal Roof
You will need 2 or more assistants for this part of the task, as steel sheeting is very heavy. The aluminum sheathing is very flexible and can be pulled from your hands by a strong wind gust. Lift the panels one at a time to the roof and secure them to the underlayment with the self-tapping wood screws fitted with rubber gaskets. Each panel is secured to its neighbor with self-tapping galvanized metal screws. Trim the last metal panel to the correct width with the jigsaw as necessary.
Step 7: Install the Rake Flashing
At the edge of the roof, install the rake flashing. If you are putting in a roof gutter, the flashing must overlap the side of the gutter closest to the roof sheathing. Place foam closure strips over the upper edge of the rake flashing and seal with butyl tape sealant, applied in a continuous bead. Ensure the flashing face is square to the roof edge.