How do Flat Roofs Drain?

Flat roofs can be a great choice for buildings due to their affordability and durability. However, if not done correctly, flat roofs are prone to water damage. Proper drainage is essential for the longevity of a flat roof, and selecting the correct drainage system is critical. Here we will discuss three common flat roof drainage systems - gutters, interior drains, and scuppers - as well as their pros and cons. 

Gutters 

Gutters are the most common form of flat roof drainage because they are low-cost and efficient when it comes to redirecting water off the roof. Gutters should be installed at a certain angle (approximately 1/4” per foot) to ensure proper water drainage. Gutters also need to be maintained over the years, as debris and leaves from storms or rain water can clog them up and create standing water. 

Pros: 

• Low-cost installation and maintenance
• Easy to install
• Can direct water away from the foundation of the building 

Cons: 

• Prone to clogging
• Requires periodic maintenance and cleaning
• Overflow from rain storms can cause damage to surrounding areas

Interior Drains 

Interior drains are often seen as the higher-cost alternative to gutters. They are installed directly into the flat roof’s membrane and include a network of pipes that drain water off the roof into a downspout.

Pros: 

• Low maintenance
• More reliable than gutters in terms of preventing roofing damage
• Can be adjusted to fit any size of flat roof 

Cons: 

• Expensive installation and maintenance costs compared to gutters
• May require frequent adjustments depending on the environment surrounding the building
• Can be difficult to install if the roof does not have the right slope 

Scuppers 

Scuppers are metal or plastic openings that allow water to drain off flat roofs. They generally come in square or rectangular shapes and are installed along the perimeter of a roof. The size and shape of scuppers should be adjusted accordingly in order to prevent water from overflowing onto the sides of a building. 

Pros: 

• Easy and cost-effective installation
• Low maintenance costs compared to gutters or interior drains
• Can be adjusted to fit any size of flat roof 

Cons: 

• Prone to clogging due to debris and leaves
• Overflow from rainstorms can cause damage to surrounding areas
• Can be difficult to install correctly if the roof does not have the right slope 

When it comes to selecting the best drainage system for your flat roof, there are a few things to consider. Gutters, interior drains, and scuppers all offer their own advantages and disadvantages. It is important to select the right drainage system for your needs in order to ensure the longevity of your roof and protect it from water damage. 

Flat Roof Repair and Inspection Services 

If you are looking to repair or replace your flat roof, make sure to contact a certified roofing professional who can assess your current roof and provide the best solution for your needs. At ACR1 Commercial Roofing, we specialize in flat roof repair and installation. Our team of certified professionals has years of experience working with flat roofs, so you can be sure that your roof is in safe hands. Contact us today to learn more!