A Guide to Flat Roof Systems

What is a Flat Roof? Any roof with a pitch of 1-10 degrees is considered a flat roof. as a result, flat roofs aren’t truly flat. Although it appears to be horizontal, it usually has a minimum slope of 1/4 inch per foot. This allows water to drain off the roof and away from the structure which prevents damage.

The terms pitch and slope refer to the angles of your roof. The relationship between the roof’s rise (the vertical change in height for each horizontal unit of the roof) and span (the distance across the roof) is known as pitch.

The relationship between the rise and run of your roof, or the horizontal change in distance across your roof, is known as slope. Runoff is caused by slope and pitch. When there is no slope or pitch, water pools or puddles, causing roof damage. Water should flow into a gutter and away from your home’s foundation. Flat roofs and low-sloped roofs do not drain as quickly as other roofing designs.

Pros and Cons of Flat Roofs

Yes, flat roofs are known for leaking, but all roofs can leak. In a sunny, rainy, or snowy region, you can have a reliable flat roof thanks to innovations in structural design in new house construction or replacing your roof to superior materials.

Pros

When compared to other types of roofing, flat roofs are the most cost-effective. They provide greater air-conditioned living area per square foot than pitched roofs. They make greater room for solar panels, passive illumination systems like skylights and tubes, and air conditioning components. They’re ideal for creating additional outside living spaces, gardening, and even greenhouses. They’re a great design for areas with a lot of wind. Perhaps you simply adore the sleek modern look. Flat roofs are more commonly found on commercial buildings than on residential structures, but that doesn’t mean you can’t have one built on your home. When choosing a flat roof, there are various factors to consider, including the materials, weather, and maintenance. The benefits and drawbacks of installing a flat roof on your home are listed below.

The Benefits of Flat Roofs

A flat roofing system is preferred by many individuals over shingles or tile roofing systems. Here are some of the advantages of having a flat roof on your house. Flat roofs are simple to construct, so you won’t have to worry about your contractors running into problems during the job.
Flat Roofs Are Long-Lasting: If long-term durability is vital to you, a flat roof is the best option. You won’t have to worry about water damage because a flat roof is water resistant. When you have a flat concrete roof, you have a roofing structure that can withstand strong winds. When you choose a flat roof for your home, the likelihood of a fallout is reduced.

Repairs Can Be Made: If a problem arises, the flat roof is just as simple to repair as it is to install. In comparison to other roofing systems, the expense of repairing or re-coating a flat roof is low. You can fix your flat roof without breaking the bank or putting yourself under a lot of stress.

Cleaning Is Simple: A flat roof is easier to reach than most systems, making maintenance simple. To keep debris from accumulating on your roof, you should remove algae, mold, and stains on a regular basis. The best approach to clean your flat roof without harming it is to use pressure washing, especially if you have a flat concrete roof.

Flat Roofing Negatives

With the good comes the bad, and it’s critical to understand the disadvantages of a roofing system before deciding if it’s ideal for your home. Here are some of the drawbacks of having a flat roof on your house. Lack of drainage is the most significant disadvantage of a flat roof, which is why it is critical to inspect your roof on a regular basis. Your drains may become clogged with snow and water if you do not inspect it on a regular basis. Clean out the drains as needed, and use a waterproof seal on a regular basis to avoid leaks. Remember that there are no slopes down which the water or snow can flow.

Snow and water aren’t the only things that might cause issues on a flat roof. Debris and dirt can accumulate. Leaves, twigs, mud, and other debris can plug the drain, causing snow and water to back up and overflow. Regularly examining and cleaning the dirt and debris off your roof might help you avoid a clogged drain.

Limited Roofing Materials: TPO, EPDM, rubber, and bitumen are the most common rolled roofing materials used on flat roofs. The materials are cheap, but they only endure ten to fifteen years. There are alternatives, such as rolled rubber roofing with rubber shingles, but they are more expensive and the materials’ longevity is unknown.

Flat roofs have very little attic or storage space beneath them. They don’t shed water or snow as well as pitched roofing does. Mold is more likely to affect them. Depending on the materials used, they may not last as long between reroofs and may require more water drainage maintenance than pitched roofing.

With the good comes the bad, and it’s critical to understand the disadvantages of a roofing system before deciding if it’s ideal for your home. Here are some of the drawbacks of having a flat roof on your house. Lack of drainage is the most significant disadvantage of a flat roof, which is why it is critical to inspect your roof on a regular basis. Your drains may become clogged with snow and water if you do not inspect it on a regular basis. Clean out the drains as needed, and use a waterproof seal on a regular basis to avoid leaks. Remember that there are no slopes down which the water or snow can flow.

Snow and water aren’t the only things that might cause issues on a flat roof. Debris and dirt can accumulate. Leaves, twigs, mud, and other debris can plug the drain, causing snow and water to back up and overflow. Regularly examining and cleaning the dirt and debris off your roof might help you avoid a clogged drain.

Limited Roofing Materials: TPO, EPDM, rubber, and bitumen are the most common rolled roofing materials used on flat roofs. The materials are cheap, but they only endure ten to fifteen years. There are alternatives, such as rolled rubber roofing with rubber shingles, but they are more expensive and the materials’ longevity is unknown.

Types of Flat Roof Systems Materials for Flat Roofs

Many historic houses still have tar and gravel roofing, which can last for many years without leaking, but locating a spot to patch the hole might be difficult. It may be time for a reroof if several patches have been performed throughout the years. There are various roofing systems and materials to pick from if you need a reroof or are building a new home with a flat roof. Built-Up Roof (BUR), Modified Bitumen Roofing, and Single-ply Membrane Roofing are the three most common roofing systems.

Built Up Roof (BUR)

Multiple layers of natural or synthetic roofing felt are alternated with hot-applied coatings of tar or asphalt in a BUR system. The top layer is commonly a hot asphalt layer with gravel on top. The gravel acts as a solar reflector and protects the layers beneath it. Instead of tar and gravel, a reflective coating is sometimes used. This stinky and dirty roofing process necessitates the use of specialized equipment and is not a do-it-yourself project. The roof becomes more resilient as more layers are added, but it also becomes heavier. It is the heaviest solution in general, thus the roofing structure must be sturdy. When done correctly, a built-up roof is still the most dependable and cost-effective option.

Modified Bitumen Roof

Modified bitumen roof systems typically consist of overlapping, single or double-ply asphalt-based sheets that are rolled out and either heat-applied or self-adhering. As an alternative for BUR, modified bitumen was developed. There’s no stench of tar here. A reflective elastomeric coating can be applied to a modified bitumen roof to seal any cracks and reflect the sun’s beams. This is a project that some do-it-yourselfers can take on. It has the same tear resistance and durability as BUR, but it is more expensive, falling between between BUR and single-ply membrane systems depending on the number of layers utilized. Single-ply Membrane
Single-ply membrane systems are the most expensive of the three types of flat roofs because they require flexible, waterproof sheets manufactured of synthetic materials. The following are some of the most common single-ply membrane roof types.

TPO (thermoplastic olefin)/PVC (polyvinyl chloride)/ EPDM (ethylene propylene diene M-class rubber)

EPDM has been around for as long as modified bitumen and has shown to be just as durable. If it is perforated, it is simple to fix. It is the most commonly used single-ply membrane material. One disadvantage is that it is black and absorbs heat. You can add a reflective coating, but it will increase the price. Both PVC and TPO membranes are light in color and can be used as a reflecting solution. TPO is less expensive than PVC, although both are more expensive than EDPM. TPO, on the other hand, is a newer product with a shaky track record in terms of reliability. Make sure you do your homework because there are a variety of TPO membrane brands to choose from. The installation and materials utilized in all three of these roofing systems can differ. Consult a specialist to determine which application is ideal for your specific needs in your specific climate.

Maintenance for Flat Roofs

• The owner of a flat roof is responsible for inspecting and maintaining the roof on a regular basis. This will make a big difference in the integrity and durability of the structure. A basic inspection should be performed twice a year and after any significant rainstorms. A roofing specialist who is well-versed in rooftop safety measures and safeguards is recommended. Checklist for flat roof inspections: Wait 48 hours after a rainstorm to clean and inspect the roof in normal circumstances. By this point, any remaining water should have evaporated. If it hasn’t, there’s a problem with the roof drains or the drainage system.
• Clean any debris from the flat roof surface, including sweeping or gathering fallen leaves or branches and clearing any loose debris or gravel that may obstruct drainage holes, to help see where any water may be collecting.
• Examine the flashings surrounding the chimney and skylights for any damage. You should get the flashing material fixed as soon as possible if it is damaged or rusted.
• Examine the integrity of the top layer of protection (usually gravel or a chipped mineral mixture) to make sure it hasn’t dispersed and left a bald region. This is essential for safeguarding the membrane beneath it, as well as providing sun and fire protection. When gravel becomes sparse on a built-up roof, the asphalt layer beneath it might dry out and break in the sun. This could result in “alligatoring,” causing the layer to leak and eventually fail.
• Examine the membranes for any punctures, rips, or wrinkles. If there is a layer of chipped material or gravel on top, it may be difficult to see. Take the time to thoroughly inspect the surface of your flat roof, regardless of its design.
• Any damage to the roof should be rectified as soon as possible to restore waterproof protection and prevent further degradation.
• If the top layer of gravel needs to be replaced or replenished, a roofing contractor should be consulted for proper placement over the roofing material’s surface.