Pros and Cons of Flat Roofing Systems

Jan 25, 2021 | Commercial

Pros and Cons of Flat Roofing Systems

There are several different roofing styles you can choose for your home or business. Today, we’re going to be looking at the pros and cons of flat roofing.
A quick note before we begin—flat roofs are not entirely flat. There is a very slight slope, about a quarter to a half-inch per foot. This helps the roof to drain properly—there may also be drainage systems installed with your roofing system to prevent water damage.

Pros of a flat roofing system

Let’s start by taking a look at the advantages of flat roofs. There are a number of features that make flat roofs a relatively attractive option…

Ease of Installation


Compared to sloped roofs, installing a flat roofing system can be a breeze. This basically means two things: installation takes less time, and it costs less. There’s also a lower risk of problems with the roof due to poor workmanship—the simplicity of the process means there’s a reduced chance of human error.

They’re relatively inexpensive

Flat roofs are often less expensive, both because of the lower labor costs associated with installation and the lower cost of needed materials. For folks looking for a budget-friendly option, flat roofs are the way to go.

They can be used for additional space

In any industry, space is at a premium. Especially in commercial environments, the last thing you want to be doing with your space is using it as storage for the large HVAC systems that most commercial spaces require. With a flat roof, you can opt for a modular, roof-mounted HVAC system, freeing up space for retail or other uses.

They’re relatively easy to care for

Have you ever tried walking on a sloped roof? It’s a tricky, and sometimes dangerous, experience. Flat roofs, on the other hand, are incredibly easy to walk on. That means that caring for the roof or the things on the roof is that much easier. From HVAC maintenance to patching weak points in the roof, that means lower labor costs and less time spent on repairs.
You can also use particular types of insulation to create a self-drying roof. This can reduce the risk of moisture build-up causing you problems, while decreasing the amount of time you’ll need to spend caring for the roof.

Cons of a flat roofing system

Of course, it’s not all upside! If it was, you’d see flat roofs everywhere. Here are some of the disadvantages that you should be aware of:

There are fewer materials you can use

Have you always dreamed of having a terracotta roof? If you’re planning on installing a flat roof, you can keep dreaming. Flat roofing systems are basically limited to being tar, rubber, or plastic-based.

They tend to have a shorter lifespan

There are roofing systems that have lifespans of 50+ years. That’s not the case with flat roofing—you’re looking at 10-20 years, and that’s if things go incredibly well. That means the advantage of flat roofing being inexpensive might not be such an advantage after all. If you end up paying more over the lifetime of the building to replace or repair your flat roof, it’s not exactly less expensive.

They’re (objectively) less aesthetically pleasing

No one can account for taste, so we apologize in advance if you find flat roofs more attractive than tiled roofs. For most, however, flat roofs are a lot less aesthetically pleasing than some of the sloped roofs on the market. That’s a consequence of having fewer materials available—you just can’t get the colors and textures you’d get out of tiled builds. Not to mention, flat roofs are much more difficult (and often impossible) to see from the ground.


A Mid-Century Modern Home common to Palm Springs, CA.

Flat roofs are often seen in mid-century modern architecture in residential settings. This architectural and design style surged in popularity in the 1950’s and 60’s, putting emphasis on large windows, open floor plans, and—you guessed it—roofs with little or no slope. These types of homes are fairly prominent in warmer, dryer regions, such as Palm Springs or Los Angeles, CA. However, if you live in colder areas of the US that are prone to harsher weather conditions, you probably won’t see mid-century homes too often.

They have inferior drainage

The reason for this is pretty obvious – if your roof is sloped, water will slide right off. While flat roofs are designed to slope enough so that water doesn’t pool, they are more prone to water-related problems.
A single flat spot or divot can lead to water accumulating pretty quickly. For this reason, they need to be monitored for moisture damage much more carefully and frequently than a sloped roof.

Who should get a flat roof?

Now that we’ve discussed some of the advantages and disadvantages of flat roofing systems, we can draw some conclusions about for whom they’re most useful.

Homeowners should generally avoid flat roofing systems, especially if they live in a region that is prone to heavy rain or snowfall. However, as we discussed previously, there are certain architectural tastes that favor the flat-roof look.
You won’t find the same space-saving advantages as businesses would because the space you generate in your home often doesn’t lead to more revenue for yourself. Homeowners are also more likely to stay in their homes for longer than one business would stay in a given building, so a longer-lasting roof is more important for homes.

Greenawalt’s business location in Pittsburgh, PA pictured with a flat roofing system.
Businesses, on the other hand, do see a number of advantages from flat roofs. The space-saving, lower labor costs, and ease of installation are all appealing to business owners. Plus, dependent upon the type of business or industry, overall aesthetics tend to matter less for the roofs of commercial buildings than they do for homeowners.

No doubt, there are exceptions to these rules. Smaller service-based businesses may find there’s no need to save space, and that the exterior aesthetics of a sloped roof help client acquisition and retention.
Now that you know a bit more about flat roofs, you may do well to learn about the materials that can be used, and what roofing system might best suit your needs. If you’re curious to learn more, get in touch with us!  

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