How to Lay Asphalt Roll Roofing

A person applying roll roofing on a flat roof.
What You'll Need
Roll roofing
Sharp knife
Roofing cement
Galvanized roofing nails
Chalk line

One of the cheapest and simplest methods for creating a waterproof roof is to use asphalt roll roofing. Although not recommended for house roofing, it is ideal for sheds and garages that have a pitch at least 16 percent from horizontal.

Step 1 – Evaluate and Prepare

Roll roofing is not tough material, so it is vital that you sweep the roof to make sure it has no stones of other objects on it before you begin to lay it. Also, if the weather is very hot or cold, installing roll roofing is not a good idea because it will either be too flexible or too brittle to use. Keep an eye on your local weather for a clear day with mild temperatures for best results.

Step 2 - Spread Roofing Cement

You need to place starter strips of roll roofing along all edges of the roof, so start by cutting pieces of roofing about 18 inches wide. Then, apply roofing cement evenly around the roof edges where these strips are going to go. Be careful not to get any on your skin in this process.

Step 3 - Apply the Edge Strips

Fit starter strips so that they overhang the roof by about half an inch. Make sure there are no bubbles under them by going over the surface with a roller to smooth them out. Nail them down once they're flat. The cement under the strips will create a good, waterproof seal.

Step 4 - Apply the First Strip

Unroll the roofing and cut a strip to the length necessary for your roof. It is best to apply these strips horizontally. Place the first strip over the starter strips, but don't overlap the roof edge. When it's positioned properly, nail the roofing down with galvanized roofing nails every four inches along the top and bottom edges. A chalk line can also make positioning easier.

Step 5 - Apply the Second Strip

Apply roofing cement to the top six inches of the first strip, making sure there is no excess. Then, cut the second strip and position it so that it overlaps the first strip to cover the cement you just spread. Once it is in position, nail it down in the same way so that the bottom nails are driven through the layer of roofing cement and create a good seal

Step 6 - Finish it Up

Continue with this process until the roof is completely covered. If you run into a situation where a strip is not long enough to cover the full width of the roof, fix it into position, and then apply roofing cement to the last six inches. Cut a strip long enough to complete the width of the roof with six inches to spare. This will overlap the short strip and form a sealed joint. Once the roof is fully covered, trim the edges with a sharp knife.

That's it! Even though asphalt roll roofing is usually used where it is not easily seen, you can still be proud of your efforts.