How Long Does a Flat Roof Last? Lifespan, Factors, and Tips

As a homeowner or a commercial property manager gaining detailed information about what factors into a flat roof lifespan can help you make an informed decision on this popular roofing option. This article will help you weigh your options on either a flat roof installation or replacement by learning more about what affects a flat roof’s longevity along with a guide to different flat roof materials and expert maintenance tips to help extend a flat roof lifespan.

Factors Affecting a Flat Roof Lifespan

A flat roof lifespan, on average, is about 20 years, but there are several factors that play into a roof’s longevity. This includes:

The roofing materials used
The quality of the installation
Upkeep and maintenance over time
The climate the roof is exposed to

A properly installed and maintained flat roof can last decades, but climate factors and materials play a role too.

Climate as a Factor

A roof’s main job is to protect the inside of a building from the elements. This, of course, means that a roof is exposed to those elements. Harsh summer heat, freezing winter temperatures, heavy snow or rainfall, or severe wind and storms can add up to shortening a flat roof lifespan, especially when compared to more temperate climates. This is where different roofing materials can play a part too, as some respond better when exposed to the elements than others.

Materials Matter: The Lifespan of Different Flat Roofing Materials

Before talking to your roofing contractor, it is helpful to learn more about the different flat roofing materials on the market.

EPDM Roofing Lifespan

EPDM roofing refers to a synthetic rubber roofing material that is commonly used on low-slope or flat roof buildings. EPDM stands for ethylene propylene diene terpolymer and is made from natural gas and oil. It is a durable and lightweight material that creates a tight, waterproof seal over the top of your roof. Known for its temperature and puncture resistant qualities, it comes in both black and white. The white creates a reflective roof as opposed to the heat absorption of the black material. The reflectivity of white EPDM can cut down on cooling costs in air-conditioned buildings. EPDM is also 100 percent recyclable from a sustainability stand-point. EPDM is manufactured in different widths and thicknesses and can be installed using one of three different methods: fully adhered, mechanically attached, or ballasted. The roofing seams are usually sealed using either a liquid adhesive or a specially manufactured roofing seam tape. EPDM roofing can last up to 50 years, depending on the quality of the installation, thickness used, and regular maintenance.

TPO Roofing Lifespan

TPO roofing refers to a low-cost, single-ply roofing membrane that is a common option for both residential and commercial low-sloped roofs. TPO stands for thermoplastic polyolefin, which is a material that is a combination of polypropylene and ethylene-propylene rubber. TPO is a white material that reflects heat and has similar energy efficient properties as white EPDM. TPO is known to be highly waterproof and resistant to harsh weather conditions and sunlight. It is also resistant to tears and punctures as well as dirt and mold. TPO comes in sheets and the seams are heat-welded together. It is also a 100 percent recyclable material. If properly installed and maintained, a TPO roof can last up to about 25 years. It does not have the longevity of other flat roofing materials, but it is less expensive than other options.

PVC Roofing Lifespan

PVC roofing refers to a single-ply roofing membrane that is made from polyvinyl chloride (PVC), which is a type of plastic polymer. It is commonly used for both commercial and residential flat-roof buildings. A PVC membrane is a highly durable and chemical resistant roofing material that is known for its ability to withstand harsh weather conditions, such as high winds, heavy rain and snow, and hail, making it a good option in more extreme climates. It is also resistant to tearing, breaking, and cracking. It is also flame resistant and highly reflective. It is installed with a heat welding method, or with adhesives and solvents. PVC roofing can last for about 30 years if properly installed and maintained.

Modified Bitumen Lifespan

Modified bitumen is an older low-slope roofing system, introduced in the United States about 40 years ago. It is a hybrid material made of both an asphalt-based membrane combined with either a polymerized rubber or plastic. It is then reinforced with fiberglass. Modified bitumen is installed using either a torch-down method that uses a propane torch to adhere the sheets to the roof or with versions that are designed to be self-adhesive. Modified bitumen is a flexible and durable material that is resistant to harsh weather conditions and extreme temperature fluctuations. It is also cost-effective and easy to repair, making it a popular flat roofing option. Modified bitumen roofs can last at least 20 years and sometimes longer when properly maintained.

Metal Roofing Lifespan

Metal roofing is becoming a more popular flat roofing option, especially for residential buildings as there are many more options on the market today. Metal roofs are made of corrugated sheets of different blends of metal, including steel, aluminum, zinc or galvanized iron. Metal roofing is highly durable and energy efficient, but the slope of a metal roof is a little higher than other flat roof options. Metal roofing systems are the most durable and have the longest lifespan of any low-slope roofing options. A metal roof can last up to 100 years, but the material and installation costs are also much higher than other options.

Flat Roof Tips: How to Prolong a Flat Roof Lifespan

Installation Quality

One way that helps prolong your flat roof lifespan is expert installation. Quality from the start of your roof’s life is sure to make that life longer. Regardless of what flat-roofing material option you choose, your roofing contractor should communicate the installation process from start to finish so you know exactly what to expect. Hiring a reputable and experienced contractor who can also give you expert tips on maintaining your roof will also go a long way to ensure quality installation.

Proactive Maintenance

Applying a proactive stance when it comes to roof maintenance can go a long way in expanding a roof lifespan. One important part of proactive maintenance is scheduled roof inspections. Frequent inspections can catch roof damage early, allowing for repairs to be done quickly and efficiently that can prolong a roof’s lifespan. Make sure the inspection covers the whole roof span. Look for warning signs that the roof coverage is damaged or inadequate. Materials that are fragile, brittle, or cracked mean they are not doing their job properly. It may be time to repair sections of your roof, replace damaged materials, or get a roof replacement. Another proactive roof maintenance step is to have flat roof insurance. This type of roof protection is more expensive than higher pitched roofs as flat roofs are considered to be a higher risk. Not all insurance companies will cover a flat roof and will usually charge higher premiums, but it is worth researching insurance options in your area.

Drainage System Cleaning

Flat roofs are not entirely flat. They do have a slight slope that assists in preventing water from collecting on the roof’s surface. This system also includes drains that can get blocked, causing water accumulation that can result in roof damage and leakage. Drains need to be cleaned to keep water flowing through them, including drain entrances and exits. Cleaning drains should be a part of any routine roof maintenance. Adding guards to the drainage system can also help prevent drain blockage by keeping branches, twigs, leaves, and other debris from clogging gutters and drains. Making drainage system cleaning a part of your routine roof maintenance can go a long way in expanding your flat roof lifespan.

Final Thoughts on a Flat Roof Lifespan

Whether you are looking at a new roof or a roof replacement, on either a commercial or residential property, there are a lot of different options for flat or low-slope roofs. Roofing materials continue to evolve and what is on the market today is much more than what was available in the past. The most important consideration is choosing the right material for your project, hiring a reputable and experienced roofing contractor to ensure quality installation, and employing proactive routine roof maintenance.

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