Flat roofs are usually seen in commercial buildings and also in some of the residential buildings. The interesting fact is that the flat roof is not entirely flat in any of the commercial or residential buildings for practical reasons. A minimum slope for a flat roof is mandatory for proper drainage and to avoid leaks, mold, or structural wear and tear. In some states in the USA, building codes are imposed to ensure all roofs have proper drainage. If your roof is flat and you frequently face water puddles, rotting of the framework, or leaks around the walls, it could be a drainage issue due to the wrong angle of the slope. In the article, you will learn more about the flat roof and its different aspects.
What is a Flat Roof?
Unlike the name, a flat roof is not actually flat. It only appears flat to the naked eye but has a minimum slope(known as pitch) of one-fourth inch vertical to twelve inches horizontal depending on the material (concrete or masonry covered by modified bitumen roofing or thermoplastic roofing) used in roofing. A flat roof is named so because it is flatter than any other roof.
The Factors That Decide the Pitch of the Flat Roof
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Amount of rainfall received—If you live in a high-rainfall area, invest in the highest-pitched roof to ensure the shedding of extra moisture.
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Roof accessories—The slope of your roof also depends on the accessories you have, such as skylights, vents, pipe boots, and chimneys, because they all affect the roof's performance and drainage accuracy.
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The speed at which water needs to drain from the slope.
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Roof design.
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The amount of snow and ice anticipated during winters—In an area with snow and ice accumulation on the roof, select the roofing material and slope in the best way possible.
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Stability of the framework structure—The framework needs to be stable, and only then can you decide the angle of the slope.
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Building codes and roofing standards—No matter what your choice and requirements, it should meet the roofing standards and building codes of the area where you stay.
The contractors decide the slope angle depending on the snow and rainfall expected in your area. In areas with heavy rain, specialized materials such as metal or tile are used.
Popular Roofing Materials
Different flat roofs are built differently based on the materials used. Some of the popular materials are as follows:
Metal
Metal roofs have evolved over the past couple of years, changing the mindset of homeowners and businesses. They are long-lasting, non-combustible, reflect heat from the roof, are easy to install, and require less repair.
Modified Bitumen Roofing
It is an asphalt-based roofing material designed for flat roofs. Its flexible design opens up multiple options for building a roofing system. The best feature is that installation is easy and can be accomplished without high-tech equipment.
PVC or TPO
Thermoplastic roof membranes (TPO) provide more stability and strength to the roof. Their white surfaces help reflect the sun's rays.
Ways to Slope a Flat Roof for Proper Drainage
The primary factor is to slope the roof at least one-quarter of an inch per horizontal foot. The way to slope the roof is discussed in the below lines:
Proper Underlayment
When investing in a new roof for commercial or residential purposes, consider durability and prevention of water seepage quality as a higher priority. Also, opt for a thicker underlayment on one edge to create more slope and shed more water from the roof.
Install Pavers
Install pavers on the top to create a slope. To ensure effective water drainage, opt for thick-edge pavers.
Use an Upgraded Drainage System
Install the gutter system drainage along the roof's edge to collect water, which is redirected from the roof via downspout.
Seek the Help of a Roofing Expert
Don't try to slope the roof or repair it yourself because you may end up doing a poor job adding to the repair cost later.
Benefits of Installing a Flat Roof
Budget-Friendly Option
Flat roofs require less labor and material than sloped roofs, lowering the cost of installation. For example: attaching TPO to the roof surface requires less material and labor to accomplish the task. You end up saving more money.
Easy Access to the Roof
Usually, it's advisable not to go to the roof, but there are situations when you have to access the roof. A flat roof is more easily accessible than the other roofing designs.
No Worries About Height Restrictions
Some states in the USA impose restrictions on the height of the roof, and in such a situation, a sloped roof has height limitations, resulting in less workable space. In contrast, flat roofs have more usable space without compromising on height restrictions.
