The flexibility of flat roofs can be beneficial in many ways and there are many material options for flat roof installation beyond the traditional roofing options. These materials can help increase the reliability of flat roofs and help avoid leaks and repairs. Commonly used flat roof materials are discussed below. Get in touch with our flat roofing contractors to learn more about the option that is most suitable for your home roofing.
Single Layer Membrane Roof
This is the latest technology in roofing and is the roofing choice in many commercial constructions. Depending on the type of material used, these roofs are technically called plastomeric or elastomeric roof membranes and are available in varieties like Polyvinyl chloride, Neoprene, Ethylene propylene diene monomer (EPDM), polymer-modified bitumens, and Chlorinated polyethylene sheets.
Of all these varieties, EPDM is the most common single-layer roofing material used in commercial and residential buildings. These are installed as thin sheet materials and are applied as a single layer to the roof. As they are made from polymer or synthetic rubber, they are elastic and flexible and capable of handling changes in temperatures.
Built-Up Roofing
Built-up roofs or BURs can be considered the great grandfather of flat roofs. These roofs have solved the low pitch roof problems for numerous years. These roofs are installed using many layers of special roofing felt that is impregnated with asphalt and embedded in bitumen applied using a hot mop. The hot-applied coal tar pitch or asphalt will blend with the roof felt that is soaked in bitumen to form a monolithic roof membrane.
The asphalt tar or roof felt or asphalt tar layering will be repeated in overlapping layers to make the roofing 2 to 4 plies thick. To protect the roofing from weather and UV rays, a wear surface of stone granules will be applied to the topmost layer of tar.
Modified Bitumen Roofing
This type of roofing was developed as a replacement for built-up roofing, making use of the BUR technology and adding polymer reinforced cap sheets or roof wear layers. Modified bitumen roofing can be installed as per the material and specific requirements of the project.
The polymer used in the roof wear layers or cap sheets offers improved flexibility and elasticity in low temperatures. Styrene-butadiene styrene (SBS) and atactic polypropylene (APP) is the commonly used polymers. SBS offers a rubber-like property to the bitumen. SBS cap sheets are installed using host asphalt tar or cold adhesives. On the other hand, APP sheets are installed by the torch applied method.