Not every roof on every structure is pitched, meaning there are many structures that have a flat roof. Flat surfaces present certain roofing challenges for even the best roofing company, making roof design and material selection very important based on the structure being protected. There are different types of flat roofs to fit a variety of needs, so when working with a roofing company, a homeowner must understand the different types, and how suitable they are in different applications.
Flat Roof Basics
Technically speaking, a flat roof is not actually “flat.” When correctly built, structures with a flat roof actually have a roofing surface that includes an angle of 10 degrees from top to bottom. This is to promote drainage and prevent standing water. These surfaces are covered in a variety of materials depending on geographical region and usual climate. Yet the most important part of any flat roof is that the roof structure itself is properly constructed to include that slight grade, and that is has well-fit sheathing panels that are securely applied. This provides the best structure on which roofing material can be applied, by a good residential roofing company, for the greatest protection.
Types of Flat Roofs to Choose
There are multiple ways in which a roofing surface is applied to a flat roof to provide durable protection from elements. These methods include the following:
Tar and Gravel, or Built-Up Roof – This type of roof is constructed by first using a primary layer of a waterproof membrane, then adding multiple layers of roofing felt adhered together with hot tar. Finally, it is finished off with a covering of tar and crushed gravel for durability. This has always been the most common flat roofing technique, but with the development of better, more leak-proof materials that require much less work to install, residential roofing companies assert that it is declining in popularity. Additionally, this application creates a very heavy roof that is prone to leaks, making it much less favorable than it was when there were fewer options available for flat roofs.
Modified Bitumen - This type of roof installation uses rolls of single-layer roofing membrane impregnated with polymer-modified bitumen (PMB) that can be easily rolled out and stuck down by adhesive as it is unrolled. This material helps cut cooling costs by reflecting heat well, and is easy to apply, although it is not as tear-resistant as other types of flat roofs.
Rubber Membrane (EPDM) – This is a true rubber material composed of ethylene propylene diene monomer, which is highly durable. It is designed to resist tears, and can be applied using fasteners or glue. This roofing material is easily patched like a tire inner tube, and is highly UV-resistant. According to roofing company experts, because it is black, it absorbs heat and can be less efficient in warmer climates.
PVC or Vinyl - Applied in rolls, then heat-welded to fit, vinyl roofs are durable, highly puncture-resistant, very heat efficient and reasonably easy to apply by any good roofing company. The main problem experienced with a PVC roof is that when applied over old asphalt roofs or tar and gravel roofs, the underlying chemicals can eat away at the PVC. Therefore, according to the best roofing companies, the correct application of this type of roof depends upon either removing any previous roofing material, or putting on separator sheets between the old and the new PVC roof to prevent this from happening.
Depending on the home or building, local weather conditions, and what type of heat efficiency is desired, one or more of the above roofing methods should be acceptable for any structure with a flat roof. Homeowners in need of a new roof can contact a residential roofing company and discuss the different types, and together, determine which application is best for their needs. To get the best, most durable roof at the most fair price, be sure to hire the best roofing company possible, who will know the most appropriate options for flat roofs in their geographical area!