What is a Rubber Roof? Your Ultimate Guide to Rubber Roofing
Rubber roofing has multiple applications—the most common being low-sloped and flat roofs.
Traditional shingles work well to repel moisture on steep roofs, with the help of gravity. But shingles don’t create the type of watertight seal needed to protect a low-pitched or flat roof from water.
On low-sloped or flat roofs, roofers often use specially-manufactured roofing materials made of rubber or PVC plastic. This type of roofing is known as rubber roofing.
- What is a Rubber Roof? (top)
- Benefits of Rubber Roofing
- Rubber Roofing Applications
- Types of Rubber Roofing
- How Long Do Rubber Roofs Last?
- Cost to Install Rubber Roofing
- Maintaining a Rubber Roof
- Rubber Roofing Alternatives
- Hire the Right Rubber Roofer
Benefits of Rubber Roofing
Single-ply rubber roofing is the ideal material for flat and low-sloped roofs because of its durability and water resistance.
Each type of rubber roofing material—whether it contains synthetic rubber polymers or plastic polymers—was specifically designed to protect low-sloped roofs from water damage.
Rubber roofing has many benefits, including the following:
• Long lifespan of 20-25 years on average and up to 50 years in some instances.
• Easy cleaning and maintenance.
• Energy savings.
• Improved curb appeal.
• Relatively short installation time.
Flat and Low-Sloped Roofs
The intended application for rubber roofing is on flat and low-sloped roofs, where shingled roofing isn’t the best option.
Shingled roofing is the perfect choice for steep-pitched roofs, but it isn’t ideal for low-sloped roofs.
This is because shingled roofing uses a stacked formation (one on top of the other with overlapping ends) to repel water as it travels downwards off the roof.
On low-sloped or flat roofs, water can drift in different directions and seep in between the shingles, causing leaks.
For roofs where shingles aren't the ideal choice, rubber roofing is often the most practical solution. Rubberized roofing materials repel moisture and protect the structure underneath from pooling water.
Rubber roofing isn’t only relegated to the field of flat roofs. It can also be used on pitched roofs, as a way to extend the lifespan of the existing roof structure and add value to the home.
On sloped roofs, rubber roofing is typically applied over the top of the existing shingles. A roofer can apply a layer of insulation onto the shingles, followed by the rubber membrane.
This option can save you money in the long run since rubber roofs tend to last longer than other types of roof replacement.
As an added benefit, installing a rubber roof on top of your shingled roof can dramatically lower your energy costs by insulating and deflecting heat away from the home.
Metal roofing is another popular low-sloped roofing option. Metal roofing can last many years, but when it becomes rusted, leaky or damaged, it can be difficult and costly to replace.
If you have a damaged metal roof, a rubber roof may be a better solution. Rather than going through the process of tearing off the existing metal roof, you can install a rubber roof over the top.
Similarly to installing a rubber roof over the top of a shingled roof, topping a metal roof with a rubber roof can improve curb appeal and reduce energy costs significantly.
Nearly all modern flat roofs are topped with one type of rubber roofing membrane or another.
But as mentioned above, not all rubber roofs are actually made of rubber, and not all are created equally. Each type of rubber roof material and system has its own pros and cons.
Ethylene propylene diene terpolymer, or EPDM, is one of the most popular materials for flat roofs.
Pros of EPDM Roofing:
- Long lifespan. EPDM has one of the longest lifespans of all rubber roofing materials.
- Original rubber roof. EPDM is the original rubber roof product, which means it’s stood the test of time.
- Lower cost. EPDM is one of the lower-cost options when it comes to rubber roofs.
Cons of EPDM Roofing:
- Absorbs heat. EPDM is naturally black, so it offers less heat protection than rubber roof materials that are lighter in color. EPDM can be ordered in grey or white for an additional cost.
- Potential weak seams. EPDM seams are sealed with adhesive or tape, which leaves them more prone to leaking than hot air-welded seams.
Thermoplastic polyolefin, or TPO, is a single-ply roofing material that is similar to EPDM but different in several key ways. First, TPO is a relatively new product in the roofing industry, which means it’s not as time-tested as EPDM and PVC roofing.
However, TPO was created as a more economical and energy-efficient alternative to these other rubber roofing materials, making it a popular choice.
Pros of TPO Roofing:
- Durable and flexible. TPO is highly flexible, which means it can better withstand impacts and other types of potential damage.
- Environmentally friendly. TPO doesn’t contain some of the chemicals used to produce other roofing materials, including chlorine. TPO is UV resistant (and can be ENERGY STAR rated), which means you can use less energy to cool your home in the summer. TPO is 100% recyclable.
- Hot air technology. TPO is hot air-welded, making the seams strong, flexible, and highly water-resistant. The seams of a TPO roof are up to four times stronger than EPDM seams, which must be sealed using adhesives.
- Color range. TPO is available in white, but it can also be manufactured in grey or black for aesthetic purposes.
Cons of TPO Roofing:
- New technology. TPO was introduced to the roofing industry in the 1990s, making it a relatively new rubber roofing material as compared to the others.
- Inconsistent formulas. TPO manufacturers are still working out the best formulations for their businesses and for their customers. Some manufacturers produce TPO products that are less expensive but more prone to failure. When you install a TPO roof, it’s essential to choose a roofer who uses a high-quality TPO product.
Polyvinyl chloride, or PVC, is similar to TPO in that it’s made of thermoplastic materials. It offers similar benefits in terms of flexibility and water-resistance, with similarly hot air-weldable seams.
However, PVC contains plasticizers and chlorine salts, giving it different benefits and drawbacks from TPO.
Pros of PVC Roofing:
- Even more flexible. The plasticizers and other chemical components of PVC rubber roofing make it even more flexible than TPO. This makes it resilient and resistant to building-settling.
- Time-tested product. Roofers have been using PVC for over 50 years. As a long-time industry favorite, it’s easier to find a roofing contractor who specializes in PVC roofing than in a newer product like TPO.
- Energy efficient. Like TPO, PVC is energy efficient and can help reduce your cooling bills during the warm summer months.
Cons of PVC Roofing:
- Chemical breakdown. The plasticizers and chemical components of PVC rubber roofing usually cause it to break down faster than TPO or EPDM.
- Contains chlorine. PVC rubber roofing contains the chemical chlorine, making it a less environmentally-friendly option than TPO.
Rubber roofing, when installed professionally, can last 25 years or more. TPO and EPDM roof systems have similar lifespans of 20 to 25 years.
High-quality TPO roofing that is reinforced with fiberglass can last even longer.
Modified bitumen roofs last an average of 10 to 12 years, and built-up roofs (BUR) last between 15 and 20 years.
Compare these lifespans to the life expectancies of other common roofing materials.
Many homeowners make the mistake of assuming that flat roof installation and work is less expensive than pitched roof work. After all, flat roofs are much less complicated to access, and it’s a lot easier to move around on a flat surface than on a sloped one.
However, many roofers will attest to the fact that working on flat roofs is more physically taxing than working on steep ones. Flat roof work may not call for a harness and brace system, but it does involve more stooping, bending, and lifting than pitched roof work.
Additionally, flat roofs require more elaborate installation processes that involve the handling of adhesives and the use of sophisticated application techniques.
For these reasons, installation and labor costs for a flat roof can be as high as—or higher than—those of a pitched roof.
Rubber roofing materials are typically more expensive than traditional composite shingles, as well. However, a rubber roof will last longer and offer more benefits than asphalt shingles or asphalt roll roofing.
If you have a rubber roof, or you’re considering installing one, it’s important to know how to maintain rubber roofing correctly.
1. Regular inspection.
Inspect your sloped rubber roof regularly from the ground, if you can. If you can’t see the top of your low-sloped or flat roof, use a ladder to climb up onto the roof safely and cautiously. (If you don’t feel safe doing so, always call a professional roofer instead.)
Inspect the roof for debris, as well as any areas that look damaged or appear to be crumbling or cracking.
Check the seams for lifting—even what may seem like minor pealing—as well as the areas around flashing and roof fixtures.
2. Gentle cleaning.
Several times per year, you should clean your flat rubber roof to remove built-up debris. Use a soft broom to gently brush leaves and other small debris off of the roof. Use a mild detergent and wet mop to lightly scrub stubborn spots.
3. Gutter care.
An essential part of maintaining any roof system is making sure your gutter system is working correctly. Each year, gently clean debris out of the gutters and check for damage. If the gutter is cracked, sagging or leaking, call a professional to make repairs.
4. Professional maintenance.
If you notice any level of damage to your rubber roof, or if your roof has been impacted by a large tree limb or other large debris, call a professional roofer for a thorough inspection.
If you need to replace your low-sloped or flat roof, you have a few different flat roof options. The following are the most popular alternatives to rubber roofing.
Asphalt Roll Roof Systems
The most common rubber roof alternative for flat and low-sloped roofs is asphalt-roll roofing. Asphalt roll roofing is applied in sheets in a fairly easy installation process.
For this reason, asphalt roll roofing is popular for sheds and small buildings, as well as for do-it-yourself projects.
However, asphalt roll is only a temporary roofing solution, as it has a very short lifespan.
Modified Bitumen and Built-Up Roofing
Modified bitumen is also known as roofing tar, and it’s a popular choice for flat and low-sloped roofs.
Modified bitumen systems can be applied as a self-adhering compound or using torch-down application. It is also used in built-up roofing (BUR) systems.
Modified bitumen and BUR roofs tend to have a shorter lifespan than rubber roofs, and they don’t offer the same energy-saving benefits.
Shingles aren’t the ideal roofing material for flat roofs, as discussed above. But it is still possible to use conventional composition shingles on a low-sloped roof.
To do so, the roofing materials need to be installed differently than you would do with a sloped roof.
Although shingled roofs can be less expensive than rubber roofs, this intricate application process will raise the price, and the roof won’t last as long as a rubber roof would.
Sealing a Metal Roof
If you’re considering sealing a leaking metal roof with a rubber roof, an alternative option is to top your existing metal roof with a one.
This would involve covering the existing roof with a layer of insulation, followed by the new metal roofing. Depending on your roof, however, installing a rubber roof may be the more affordable option.
Another option if your metal roof is leaking is to reseal the roof with fiberglass webbing.
As with any other type of roof, hiring the right rubber roofing contractor is the most important step.
When installed correctly by a skilled roofer, a rubber roof can last 20 to 25 years.
But an incorrectly installed rubber roof will need to be replaced within just a few years. More importantly, a roof that’s installed incorrectly can cause damage to the structure underneath.
If you’re in the D.C. area and in need of a rubber roof contractor, contact us at Capitol Improvements for a quote.