Why are Flat Roofs Common on Large Commercial Buildings?

Jun 27, 2019 | Roofing

Flat roofs are roofs that are almost completely level, in contrast to the many types of sloped roofs we are used to seeing in residential areas. Flat roofs still have a slope, or “pitch”, of up to 12 degrees. Flat roofs have been around for a long time, and in the past have mostly been used in desert climates where the worry of strong rainstorms was practically non-existent. In third world countries, such rooftops are used as storage areas, and even as a place to do clean dishes and laundry or raise livestock.

So why are they suddenly becoming more and more popular in first world countries, with commercial buildings throughout the world commonly being spotted with flat roofs? 

It seems that there are many pros to having a flat roof, especially for commercial buildings. Thanks to the internet and social media, this information is more readily available to builders and buyers alike.

This is likely the cause of the flat roof’s recent surge of popularity, but what are these pros and how do they benefit us?

They are Cost Efficient

Flat roofs are incredibly cost-efficient, and they cost less due to many different reasons. Starting with construction, flat roofs require much fewer materials compared to regularly pitched roofs. The materials usually used in flat roofs are under layers and a top coat, which is usually made up of modified bitumen, asphalt, PVC, or rubber. These materials are also more affordable than the typical materials used for regularly sloped roofs, and flat roofs have less surface area to cover, which means great savings. To top it all off, they’re much easier to set up, saving you time and money on labor and installation costs!

They are also cost efficient because they can last for about 30-50 years, depending on what material you go with. Flat roofs are built with tar and gravel, giving them a tough exterior that is resistant to damage. With proper maintenance including weatherproof coating, a flat roof can withstand some of the toughest wind and rain storms. This means you don’t need as large of a budget kept for roof maintenance.

They’re Easy to Maintain

Gone are the days of falling off precariously angled shingles, as flat roofs are…well, flat. This means that the roof is now much easier to get to and much safer to walk around on than a regularly sloped roof. You also don’t have to use other equipment like ladders, unlike roofs with slopes or valleys. This makes it less time consuming and much easier to find and deal with leaks and damages.

When thinking of maintaining roofs, the thing that comes to mind after shingle health is probably gutters. Nobody wants the job of cleaning out year old, half composted leaves and garbage that have found their way into the roof’s gutters. Flat roofed building owners do not have to worry about gutters at all, as they allow commercial properties to install a new type of water removal system. A reliable rainwater roll-off system ensures the rain will not clog or damage any flat roof drain. These new systems are even able to redistribute rainwater as a renewable resource to water rooftop garden plants or fountains.

They Are an Efficient Use of Space

Commercial properties usually have a very large selection of assets, so they need to optimize the space of their buildings. The flat roof, allowing air conditioner units, and solar panels, and other objects to be installed on the roof, maximizing interior surface area. Industrial properties use their flat roofs for storage, as they can support the weight of their ventilation and HVAC systems safely. Extra roof space can also be used for projects like rooftop gardens, making our world a greener place. Large commercial buildings such as hotels can even have a night sky bar area or deck. With careful architecture and design, flat roofs can even accommodate pools!

Visually Appealing

Flat roofs are completely customizable, with a variety of different upgrades available. As previously mentioned, some are turned into green roofs by adding plants on the surface. These plants not only look appealing while helping the environment, but they will also help extend the life of a flat roof by absorbing water to prevent leaks and damages. Redesigning has never been easier for building owners’ wallets, as the installation fees and material costs are much lower for flat roofs compared to regularly angled roofs.


There are so many lucrative benefits to flat roofs that commercial building owners are benefiting from. These benefits are now also slowly being reaped by homeowners around the globe, which have opted to install flat roofs rather than pitched roofs onto their homes. Having more flat buildings in urban and residential areas would be a great space saver overall, allowing more people to have homes and offering up more space for gardens and trees.

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