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All You Need to Know About Flat Roofs

As the name suggests flat roof is any roof that stands flat on top of a house or a residential building. While the roof is called flat, it doesn’t necessarily have to be 0°. Instead, it is allowed for this roof to be up to 10° sloped.

They are very popular in hot and arid climates and are also a great solution in cases when homeowners are not certain whether or not they will add additional floors. Furthermore, majority of commercial buildings in the world have this kind of a roof.

Keep in mind that this kind of a roof is not only common for US; they can be found all over the world and especially in hot climates. One of its biggest benefits is its ability to reflect the sun and reduce overall warmth within a home. They are usually made from stone and similar materials making them ideal in regions where wood is scarce.

Historically, these roofs were extremely popular in Arabic, Persian and Egyptian architecture. Over time, as their influence spread, they also became widespread all over Mediterranean.

How do you build a flat roof?

There are approximately 16 different components that are used for construction of flat roofs. Each one of them is valuable and has a different purpose. Although you might think they are simply, they do require some construction prowess to build.

It is very important for a flat roof to have a fall of at least 1 to 80. This allows it to have a smooth surface on top where you can place plastic or metal shingles. On the other hand, a fall of 1:60 allows roofers to place a felt as well as other coarse roof coverings.

Basically, fall allows a proper distribution of water. Shallow falls can cause issues as water puddles will start forming on the roof. Needless to say, this is how leaks start appearing. Excess moisture is also good for mold and algae; something you can definitely live without.

Before you start with anything, keep in mind that you have to have a flat base. You will use it to place roof covering. All you need here is some good quality plywood that is at least 18 millimeters thick. Sometimes, you will have to place insulation as well. This is required for flat roofs.

By affixing sheets of plywood to the flat roof joists, you’re able to create a flat base. On top of flat roof joist, roofer will have to put panels with long edges. The panels are staggered in order to provide a better, more stable surface. Additionally, you can use timber noggins as a way of increasing durability.

Flat roofing venting oftentimes relies on expansion gap that is placed between the decking board. Because of that, joints will have to be taped in order to prevent product from dropping through gaps.

Types of flat roofs you should consider

Whether we’re talking about commercial properties or residential structures, there are various flat roofs that can be installed. Here are some of the most popular options:

Modified bitumen

Modified bitumen is actually a single-ply rolled roof that has a mineral-based wear surface and is very resistant to extreme weathers. We can differentiate two systems: torch-down and peel-and-stick. Torch-down systems involve heating the adhesive as the material is unrolled. Newer peel-and-stick systems are safer and easier. The material can easily be installed by the homeowner so there is no real need to hire roofers for installation. Modified bitumen roofs are moderately expensive and are pretty good in terms of reflecting sunlight. This can significantly reduce your cooling costs. The biggest issue comes with its torch-down application. The process can be really hazardous. Also, modified bitumen is not as resistant to tears.

Rubber membrane

Rubber membrane is also known as EPDM. The material is very strong, can last for a long time but also provides lots of sunlight resistance. You can easily anchor it by using fasteners, it can be glued or ballasted with stone. Like modified bitumen, it is a great material for inexperienced homeowners as its installation is pretty straightforward. It is also very light making it an ideal choice for weaker, more fickle structures that cannot withstand too much weight. EPDM’s biggest issues are its price as well as the fact it can easily be punctured.

Built-up roof

Built-up roof or BUR is based on hot tar and gravel. Manufacturers use at least 3 plies to construct it. They are alternated with hot tar and are ballasted by a layer of smooth river stone. Back in the day, most BUR roofs were relying on tar paper but today, with the development of technology, a more modern, fiberglass membranes are in use. BUR roofs are very cheap and are pretty decent against fire. Alas, this type of a product is particularly heavy. We also don’t recommend that you install it yourself. Gravel used for this roof can cause certain issues later on.

With this article, you know more about flat roofs. Now, all you have to do is chose which material you want for your home and to call a trusted roofing company to help you out!

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