Modern style flat roof house with a balcony and railing

Flat Roof Materials: Which is the Best Choice?

Flat roof materials are needed for your flat roof house, so which one should you choose?  While you may love the look of a modern flat roof home or business building, you should also be aware of the potential leak concerns. Even though a flat roof may seem to look like it is completely flat, it does, in fact, have a slight pitch to it.  This allows the water to run off properly in the right direction.

There are four major ways to successfully install a flat roof.  These are:

Let’s take a look at what flat roof materials are possible choices for your home or business.

Modern style flat roof house in black and white
Stylish flat roof houses like this one are making a comeback.

Modified Bitumen Roofing

In the 1960s they developed the modified bitumen style of roof to replace that of the common flat roof material BUR (built-up roof).  There are a variety of methods to install this sort of roofing, including:

  • Self-adhered
  • Hot-applied
  • Cold-applied
  • Torch-applied

This technology is similar to that of BUR flat roof materials, but with added layers of polymer and cap sheets to reinforce the roof wear layers.  These polymers add additional flexibility and elasticity in the cap sheet during cooler weather.  

Styrene Butadiene Styrene (SBS) and Atactic Polypropylene (APP) are the two more common flat roof materials in this category.  They are often used in this method of installation on a flat roof house.  While SBS is typically installed with hot asphalt tar or cold adhesives, APP is installed by heating it with a torch.

Built-up Roof

Built-up roofing is the oldest method of installing a flat roof on a home or business building.  It is the grandfather of them all and started about 120 years ago!  

This style of roofing is done by using the flat roof material asphalt-impregnated felt that has embedded bitumen in it with a hot mop.  The process is repeated 2-4 times to ensure there is a good layer of protection on the flat roof house.  

When the roof is complete a layer of fine stones or pebbles is installed to help protect it from the sun’s UV rays.

Asphalt and gravel built-up-roofing surface on a flat roof with with vents projecting upward.
(Pictured) Traditional built-up style flat roof with gravel

Single Layer Membrane Roof

This is a single layer roof, which is completely different from the other two options.  This is very common in commercial roofs and comes in a few different options, depending on the application.  Let’s take a look at the flat roof material options for a single layer membrane roof.

  • Polymer-modified bitumens
  • EPDM (ethylene propylene diene monomer)
  • Chlorinated polyethylene and chlorosulfonated polyethylene sheets
  • PVC (polyvinyl chloride)
  • TPO (Thermoplastic Polyolefin)

These are some more examples of flat roof materials.  Flat roof materials as you can see come in a variety of types.  It all depends on how big the roof is and what the expectations of that particular application are.  Your roofing contractor can go over the various flat roof materials to help you determine what is the very best option for you.  Here is a link to a recent article where we offer a comparison between two of today’s most popular choices, TPO vs. EPDM.

Standing Seam Metal Roofing

While it’s true that this is a viable option for a flat roof installation, it is generally not the first option for most people. When using metal you will typically need special coatings added to insure the inherent durability of metal panels for UV protection in a flat roof application.

We strongly encourage owners with flat metal roofs to consider foam roofing when weighing options for flat roof problems. Then, if you add an elastomeric coating, this could allow your roof to potentially last the lifetime of your building, provided you have regular roof inspections done.

While foam roofing and elastomeric coatings are the best options for an existing metal flat roof, we generally encourage clients to consider other options rather than metal for new flat roof construction. This is primarily because your standing seam metal roof cost is quite high in comparison with other long-lasting flat roof materials, even over a longer time period.

When compared to a more conventional approach with new advanced material options, a standing seam metal roof installation is often shown to be cost-prohibitive.

Flat Roof Building Materials

The idea is to protect your building and what is inside for a very long time for the most reasonable price.  The solution is to have the proper roofing installed for your particular building size and type.  

Call the Roof Lux experts who have plenty of professional experience working with flat roof materials. They can discuss the various options with you.  There are, of course, pros and cons to each of the flat roof solutions.  We want you to know the options so you can get the best roof for your money.

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