What Is Roll Roofing, and How Do You Install It? (2024 Guide)

Roll roofing is an asphalt sheet commonly used to cover low-slope roofs, especially on commercial buildings. It’s made from similar materials to shingles and is sold in 100-foot rolls. Homeowners typically use roll roofing on flat roof sections of their homes — like garages, porches, and additions — because it’s durable, affordable, and easier to apply than shingles.

With proper maintenance, roll roofing has a typical life expectancy of 12 to 20 years. Here’s what else you need to know about roll roofing.

What is roll roofing?

Roll roofing is manufactured as a modified bitumen (asphalt) membrane. It consists of fiberglass felt or polyester mat saturated in asphalt and covered with granules in a manufacturing process similar to standard asphalt shingles. Because the material is typically sold in large quantities — most often 100-foot rolls — choosing roll roofing can be an affordable way to cover large roof areas.

The modified bitumen membranes are durable, flexible, and provide excellent protection from the elements. They are also versatile, as they can be applied using a number of methods: by brush or roller, sprayed on, torched on, or set in hot bitumen.

Homeowners typically use roll roofing on the flat roof sections of their home, like garages, porches, carports, overhangs, storage sheds, and additions.

Roll roofing materials

Roll roofing membranes are manufactured with a few layers: a roofing felt or polyester mat, an asphalt coating, and a granule surfaced facer.

• Polyester reinforcement: Polyester exhibits high puncture resistance, tear strength, and durability to withstand high roof traffic.
• Fiberglass reinforcement: Compared to polyester, fiberglass felt has better dimensional stability and tensile strength, meaning it’s less affected by heat and roof stress or movement. 
• Modified bitumen: This material is made up of 10% to 15% styrene-butadiene-styrene, which is a rubber polymer added to the asphalt product. It’s often called SBS and has increased durability and abrasion resistance, making it a long-lasting roofing option.
• Granule surfacing: Granule surfacing is applied to SBS or other materials to provide UV protection and prevent asphalt oxidation.

How much does roll roofing cost?

The cost to install roll roofing is $421, including materials. As mentioned, asphalt roofing rolls are a low-cost option for homes with flat roofs. If you plan to complete this project on your own, chances are you already have some of this equipment — like a ladder, tape measure, and PPE — which would lower that figure.

Of course, this doesn’t account for the roll roofing materials themselves. Depending on the type of roofing material you choose, costs are as follows:

• Roll roofing: $100 to $150 per 100-square-foot sheet
• Roofing adhesive: $50 to $100 per 5-gallon bucket
• Roofing cement: $10 to $20 per 1-gallon bucket

According to U.S. Census data, the average home’s roof in the U.S. is about 1,700 square feet. That means you’d be looking at 17 rolls of roofing material ($1,700 to $2,550) plus a corresponding amount of adhesive and cement.

If you hire a professional roofer, you’ll pay for labor and materials. The cost of labor in your area will determine the final pricing. You’ll likely pay between $1.50 and $5 per square foot ($2,550 to $8,500 for an average-sized roof).

Pros and cons of roll roofing

Roll roofing provides several advantages for use on the flat sections of your roof, but there are also drawbacks homeowners should be aware of. Before you decide to install roll roofing on your home, here are some key pros and cons.

Rolled roofing pros

• Affordability: Roll roofing is a cost-effective option for homeowners. The lower material and installation costs make it an ideal choice for even the tightest budgets.
• Versatility: Roll roofing can be applied with various application methods. The roll roofing membrane can be applied with an adhesive, self-adhesive, or torch-applied.
• Durability: Roll roofing provides excellent durability and weather resistance. It provides superior performance in harsh weather conditions.
• Ease of installation: A significant advantage to homeowners is that roll roofing can be installed as a DIY project. It’s easy to install and requires minimal tools, so labor costs should be low whether you apply it yourself or hire a professional contractor.
• Quick installation: The installation is relatively easy and takes little time, thanks to the 100-foot-long standard roll size and minimal application procedures. This can rapidly expedite your roofing project.
• Ease and affordability to recover: When roll roofing reaches the end of its service life, it may not need a full removal. If there are no severe defects to the roof deck or insulation, the material can simply be covered with additional roll roofing or a coating. This eliminates the high costs of roof removal and re-roofing.

Rolled roofing cons

• Limited lifespan: Roll roofing typically has a service life of 15 to 20 years. This is substantially lower than shingles or metal materials that can last twice as long.
• Limited aesthetic options: Even though roll roofing is manufactured with the same material components as shingles, including granule surfacing,  they are only available in a limited range of colors.
• Ponding water: Roll roofing can degrade when exposed to ponding water, impacting lifespan. Adding an artificial slope to the roof or drains in low areas is a good idea to help eliminate this problem.
• Maintenance at seams: Roll roofing membranes have a standard width of 36 inches, so the sheets need to be joined every few feet. These seams are vulnerable to becoming unattached over time and need routine roof maintenance to prevent moisture entry.
• Surface wear: The asphalt used in roll roofing oxidizes after long-term ultraviolet exposure. This will make the material brittle, leading to cracks and splits. The granule surfacing outer layer protects against UV exposure, but over time, the granules will dissipate, and a top coating may be required to extend the material’s service life.

How to install roll roofing

Roll roofing is relatively easy to apply. It requires few tools and can be completed as a DIY project by homeowners who follow all roof safety procedures.

The material is versatile and can be applied using several techniques. The most common application method is fully sticking the roll roofing to an adhesive. Some manufacturers offer self-adhered rolls, but others require a separate adhesive.

The material can also be torch-applied or adhered to hot bitumen. We do not recommend these applications for homeowners, as they present safety concerns and require professional training.

Tools and materials you’ll need

If you’re looking to DIY your roll roofing installation, here’s a list of tools and materials you may need in addition to the roofing material and adhesive:

*Prices are accurate as of the time of publication and are rounded up to the nearest dollar.

To determine how much roll roofing material you need, measure your flat roof by length and width (in feet), then multiply these numbers to find the area. We recommend increasing the total by 10% to account for material waste.

Roll roofing is available in 100-foot rolls, so divide the area total by 100 to determine the number of rolls you need.

You will need to complete similar calculations to determine adhesives and other component materials. Working with your local roof material supplier to determine your needs would be best.

Installation process

Applying roll roofing is similar to installing carpet in some respects, as both methods include adhering materials to horizontal surfaces. The primary difference is that roll roofing is applied at elevated heights and outside, exposing you to the elements.

Safety is paramount, so use proper personal protective equipment (safety glasses, gloves, work boots, etc.) and, more importantly, account for fall protection. If you are uncomfortable working at heights, hire a professional roofer to complete the project.

If you are comfortable with home improvement projects and prefer going the DIY route, first ensure that the pitch of your roof is low enough for roll roofing. Once you’ve determined that, here are the general steps to installing roll roofing:

Preparing your roof

There are a couple of actions to take before you begin your roll roofing installation:

• Examine your roof deck: Your roof deck must be in good condition to apply roll roofing. Make any necessary repairs, and ensure the deck is clean, dry, and free of any contaminants, debris, oils, or standing water. Sweep with a broom to clean the surface.
• Install the drip edge flashing: Install drip edge flashing around the entire roof perimeter. Set the drip edge in roof cement and nail down the flashing over the top.

Preparing your materials

Prepping your materials will save you time during the application process:

• Cut the rolls: The modified bitumen rolls are 100 feet long. More than likely, your roof will not fit the whole roll. Measure the required length and use a utility knife to cut the rolls. You may want to add a few feet to the measurement to ensure you have enough material. Lay the cut strips on the roof.
• Place adhesive pails: Roof adhesive is typically sold in five-gallon buckets. Strategically placing a few buckets of adhesive around the roof area can save you time during the application process, as the materials will be right where you need them.
• Mark your rows: Bitumen roofing rolls are 36 inches wide and should be set in slightly overlapping rows. Mark the rows by chalk line prior to application so you know where to apply adhesive. Measure and mark the underlayment every 35 inches and the cap sheet every 32 inches. This ensures overlap at the seams.

Installing the roll roofing

When your roof and materials are prepped, it’s time to install your roll roofing:

• Apply the roof adhesive or roof primer: If you are not using a self-adhering product, you’ll need to apply an adhesive to your roof. Roll out the manufacturer-recommended amount of adhesive with a paint roller inside your chalk lines. Ensure a full and even application that covers the entire area. If your roll roofing is self-adhering, you may need to apply a roof primer following the same procedure.
• Install the roll roofing: Apply the roll roofing to the adhesive or primed roof. Ensure each sheet is straight and free of any wrinkles, and remember that the sheets should overlap a minimum of 3 inches at the ends and sides. We recommend pushing a broom over each applied sheet to ensure full adhesion.
• Install the top layer of roll roofing: Roll roofing can be applied in two layers — a base sheet and a cap sheet — for added waterproofing. If using two layers, apply the cap sheet so it’s fully bonded to the base and has overlapping sides and ends per manufacturer requirements. Slightly offset the layers to avoid overlapping seams.
• Seal the seams: Next, seal all seams with roofing cement or adhesive. Apply a generous amount of material with a trowel to cover the entire seam area.
• Apply flashings at terminations and penetrations: Finally, apply roof flashing at all penetrations, terminations, and walls.
• Clean the roof area: Once the new roof cover is installed, trim any excess material and remove all material, tools, and debris from the area.

Roll roofing maintenance

Proper roof maintenance will extend the service life of roll roofing and minimize the need for costly roof repairs or replacements. Inspect your roof regularly to identify any signs of damage or needed maintenance.

Inspecting your roof in the fall and again in the spring is best to spot damage from harsh winter weather. We also recommend inspecting the roof after any storms, elevated winds, or heavy snowfall. Make sure you clean your roof, too, to ensure it stays in peak condition.

Here are some roll roofing maintenance practices to follow:

• Check for openings at seams and properly repair all defects.
• Inspect flashings for openings, splits, and loose or buckled material.
• Clean the roof surface of all debris, leaves, and tree branches.
• Clean gutters and downspouts regularly to prevent water backup. Check that any interior drains are debris-free to ensure proper water flow.
• Trim trees to eliminate the risk of falling branches damaging the roof.
• If you live in a region that experiences snowfall, remove heavy snow buildup to avoid potential roof collapse from excessive weight.
• Look for wear from UV exposure and loss of granules. If you see damage, apply a reflective roof coating on the mineral surface to extend the roof’s service life.

Frequently asked questions

How long does roll roofing last?

Roll roofing has a life expectancy of 15 to 20 years. Make sure to properly maintain your roll roofing to extend its lifespan and avoid costly repairs or replacement.

Can you install roll roofing on a sloped roof?

The modified bitumen material used for roll roofing is manufactured for application on flat roof areas. While roll roofing can be applied on steeper pitched roofs, it requires a different installation process. We recommend hiring a professional roofing contractor if you are considering rolled roofing for a sloped roof.

Is roll roofing fire-resistant?

Roll roofing material includes a fire-retardant formulation that provides excellent fire resistance. Federal building codes require that all manufactured materials used for roofing in the U.S. must pass a UL fire rating test for fire exposure. Contact the manufacturer of your roll roofing to ask about their UL rating.