How to Install Roll Roofing

by Mark Soto
Flat roof installation with propane blowtorch during construction works with roofing felt. Heating and melting bitumen roofing felt.

Roll Roofing Installation at a Glance

  • Tools & Materials: Roofing material, ladder, roofing cement, paintbrush, caulk gun, roofing nails, nailer, hammer
  • Step 1: Prep roof
  • Step 2: Apply roofing cement
  • Step 3: Attach base sheet
  • Step 4: Attach second sheet
  • Step 5: Seal vents
  • Step 6: Overlap valleys

Roll roofing is a cost-effective solution for many commercial buildings and even some residential homes. It offers benefits like budget-friendliness and easy installation that other roofing systems can’t match. For buildings or houses with a flat roof or low-pitch roof, roll roofing can be a great solution to your roofing needs.

This May Also Interest You: You Don’t Have to Be Rolling in It to Afford a New Roof: Roll Roofing Installation Costs

If you plan on installing roll roofing as a DIY project, it’s essential to know a few key things. First off, it’s not the most beginner-friendly project, but it’s not impossible to do. You just need the right tools, knowledge and caution to do it correctly since you are working on your home’s first line of defense against the outdoors.

Here’s a complete guide on installing roll roofing, along with other essential information you’ll need to know.

Types of Roll Roofing

Dallas Werner, owner of First American Roofing & Siding, said there are four main types of roll roofing: EPDM roofing, rubber roofing, bitumen roofing, and thermoplastic roofing. Each kind is made of different materials and varies in cost. Thermoplastic roofing is one of the more popular choices today. There are also different finishes for roll roofing. Depending on your purposes, you can get a mineral finish, smooth finish or choose from various other options.

Pros and Cons of Roll Roofing

Roll roofing can provide substantial benefits for the right person. Werner said it's relatively inexpensive, can be cut to size and installs very quickly relative to other roofing materials. Due to the ease of and speed of installation, labor costs are low. It's also easy to transport and is an excellent choice for roofs with a low incline.

Unfortunately, roll roofing isn't the most durable option. It has a short lifespan of anywhere from 5 to 15 years — relatively low compared to other roofing materials. The lack of layers doesn’t give it as much shielding defense as different types. It's also not the most aesthetic roofing material, and it’s not the best choice if you want to improve the resale value of a home.

Do You Need Underlayment for Roll Roofing?

Roll roofing does not require underlayment, but it’s well worth the added effort and cost to install. Roof underlayment is an extra layer of protection against the rain, snow and other things that lead to excessive water. To install it, you just nail it to your roof and ensure that it’s completely smooth with no wrinkles before adding the roofing material.

More Related Articles:

Six Steps to Install Roll Roofing

Materials Required

Installing roll roofing is no simple project. There are several roofing tools and general tools you’ll need apart from the roofing material. To start, you’ll need a ladder, roofing cement, paintbrush, caulk gun, roofing nails, nailer and hammer.

Step 1: Prepare the Roof

In preparation for installing the roofing material, you first want to clean the roof. Remove any debris from the current surface and ensure there is nothing in the way. You can use a broom to sweep things or even a leaf blower to blow them away. You should also check that any loose screws or nails are removed.

You should also consider the temperature of the day. Ideally, you want it to be at least 40 degrees Fahrenheit (4 degrees Celsius), as anything colder than that can cause problems. If you have any damaged wood, it’s a good idea to replace it.

Step 2: Apply Roofing Cement to the Edges

You will need to apply roofing cement at different points of the project. Roofing cement has adhesive properties that help things stick together, which is why it’s commonly used in roll roofing and for other roof materials. To start off, add roofing cement to the edges before you attach the first sheet. Add roofing cement using a caulk gun and then spread it around using a brush.

Step 3: Attach the Base Sheet

Unroll the base sheet of the roofing material over the surface. It should overhang the drip edges by around 1/4 inch (6 millimeters). Depending on the type of material you use, you either nail it in place, or it might be sticky enough to simply attach to the surface.

If your material requires nailing or uses special fasteners, then do each 8 to 10 inches (20 to 25 centimeters) apart. As a helpful tip, rub your feet against the material as you move backward while nailing. This is done to stretch the material. Also, make sure the nails are at least an inch (2 to 3 centimeters) away from the edges.

Step 4: Attach the Second Sheet

After adding the first sheet, spread roofing cement along the edges of it. Then cover the second sheet underneath with it before placing it overlapping the first sheet.

The second sheet should overlap the first sheet anywhere from 4 to 6 inches (10 to 15 centimeters). There are several different ways you can attach and secure the second sheet. Some materials use special screws, and others require using a roofing torch to heat the material.

Use chalk so the second sheet gets rolled in the correct position. Once it’s in the right position, you can use the chosen method to install the roll roofing sheet. If you’re heating it up with a roofing torch, simply move across the roof and ensure you cover every area.

Step 5: Seal the Vents

If you have any vents around the roof, you will want to seal these with roofing cement. To seal vents, start by cutting a circle around the sheet where it’s supposed to go. Ideally, cut the hole so that the vent overlaps it. Before adding the vent, spread roofing cement around the edges of the hole. Then lay down the vent and make sure it seals by pressing on top of it. Add roofing nails to further secure the vent if needed.

Step 6: Overlap the Valleys

After you add both sheets to the roof’s surface, you will want to overlay the valleys. Start by cutting the piece of the base sheet to add over it and make sure that it’s 18 inches (45 centimeters) wide. Add roofing cement to the edges of where you will install the sheet before slowly setting it down. Once you have it set, add the nails or screws at least 8 to 12 inches (20 to 30 centimeters) away from the center.

At this point, you’ll add the piece of roll roofing material that is 36 inches (1 meter) wide. Be sure to add roofing cement to the edges once more before setting it down. Secure it based on the method that is required for the material.