Roll roofing is one of the few roofing materials that can easily be installed by the novice. Usually used on flat roofs or roofs with a slight slope, this is an excellent way to finish a garage or shed. If you are adding a porch, roll roofing is a good way to finish the roof if you are planning on building it yourself.
Roll roofing is easiest to install because it comes in long rolls that can be cut to fit the space and then are just nailed into place. Before beginning this project, you should be aware that it should be at least 50 degrees before you attempt to install roll roofing. A colder temperature could cause your roofing to crack as you unroll it. You should also be sure that the rolls are acclimated to the temperature before you beginning installing it.
The easiest way to do this is to put the rolls on the roof and let them sit while you attach drip edge to all of the edges of the roof. This material, usually made of plastic, prevents water from working its way underneath the roofing from the edge of the roof. It is essential that you nail drip edging to all of the edges of the roof, mitering the corners, before you install the roofing. Once the drip edging is installed, your rolls should be ready to be installed.
Make sure the roof is perfectly clean before beginning any installation. Then start with any valleys on the roof. You should use an 18 inch wide roll, running it the length of the valley. Unroll the roofing until it covers the valley, then attach it using roofing nails. When you install the roofing you should place the nails about ¾ inch from the edge of the roll and spaced six inches apart. Trim the edges of the roll that extend past the roof. Then attach a piece of roofing that 36 inches wide directly over the 18 inch roofing in the same manner.
With the valleys well covered, you can install the roll roofing over the rest of the roof. Start by creating a chalk line that is 35 inches from the edge of your roof and parallel to it. Unroll the roofing, allowing for an overhang of about an inch, lining it up with your chalk line. Install it by hammering roofing nails every 3 inches, ¾ inches from the edge of the decking underneath. Don’t hammer nails into the long edge that is furthest away from the roof; you’ll finish that edge in the next step.
Snap a chalk line that is 34″ from the edge of the roll you just installed. Then apply roofing cement on the edge of the row you just installed, making it about 2 inches wide. It may help to snap another chalk line to insure you get the proper width. With the cement applied over the edge, unroll the next piece over the cement, lining it up with the chalk line on the roof. To further secure the roll, nail through the seam with roofing nails spaced 3 inches, ¾ inches from the edge of the roofing. Be sure to secure the short edges of each row with nails as well.
Eventually your roll will be too short to complete a full row. If this is the case, you can create a vertical seam and continue laying the rows. To do this, create an overlap of six inches between the short edges of the two rolls, adhering them together with cement. Then nail the exposed short edge with nails spaced every 3 inches. You can then continue with the installation.
There are two typical obstacles you may have to work around when installing this material. The first are vent pipes. To begin, install rows until you reach the course that is in the area of the vent pipe. To create a good seal, take a square of roofing and cut a hole out of the center that will exactly fit the diameter of the vent pipe. Place the square over the pipe and cover the bottom of the patch with cement. You can then roll the next row over the area, making a notch to accommodate the pipe.
The second obstacle is finishing roof valleys. To do this, you should trim each row on the roof to be ½ inch from the center of the valley. Then apply cement to bond the roofing on the valley with each row you have installed. Then roll a final 12 inch piece of roofing over the valley seam, securing with cement and nails.
For a small project such as a porch or garage, this project can be completed by a homeowner over the course of a single day. If you have a larger project, or are considering replacing the roof on your house, call a professional. Roll roofing is seldom a good choice for residential construction and a professional roofer should be able to complete the job quicker than you could.
