Nothing caps off a mid-century modern home or historic brownstone quite like a flat roof. Likewise, flat roofs have long been the darling of commercial builders who prefer to house HVAC systems on the roofs of storefronts and strip malls around the Baltimore area.
What is a flat roof?
The answer may seem obvious, but defining a flat roof is more complicated than first glance. You see, flat roofs are not actually flat. Instead, they are sloped at less than a 10 degree pitch. If a roof was truly flat, water, snow, ice and debris would collect and stress the trusses underneath causing the roof to leak and collapse. Popular in arid climates, flat roofs have such a low slope that they allow for additional living and storage space on the top of buildings that would otherwise go unused. For commercial buildings, this means having the ability to install an HVAC system on the roof instead of taking up valuable parking or access space with ventilation systems.
What are flat roofs made from?
There are three basic types of flat roofs in the marketplace, each with its own set of pros and cons.
1. Built-Up Roof (BUR)
A BUR is made from layers of tar, gravel and smooth river rock. A fiberglass membrane is laid on the roof deck and layers of tar and gravel are applied to the surface of the roof and finished off with river rock for a smoother surface. While inexpensive, a BUR is heavy and usually requires additional reinforcement to the trusses underneath. It is also difficult to determine where leaks are coming from should they develop.
2. Modified Bitumen
A mineral-based ice and water shield is applied to the roof deck with heat-activated adhesives. While any torch-down roofing should be professionally installed, newer peel-and-stick roof tiles can be installed by homeowners who are looking to repair a flat roof. Even though a modified bitumen roof is lightweight, it does not hold up to wear and traffic well.
3. EPDM (Rubber membrane)
EPDM (short for ethylene propylene diene monomer) is rubber similar to what you would find in an inner tube, except it is manufactured to be UV and weather resistant. Light and resistant to wear and tear, small areas of EPDM roofing can be patched should leaks develop. However, the standard black color absorbs heat and lighter colors can add as much as 30 percent to the cost of your overall roof.
How often should a flat roof be replaced?
Depending on the material used, the method of installation, and other factors like weather and wear and tear, a flat roof can last up to 20 years. However, most flat roofs require regular check-ups by expert roofing contractors who can spot problems before they damage your home or commercial building. If your flat roof is 10 years old or older, consider having it inspected once a year for any signs of wear and tear.
Flat roofs have been a fixture in American architecture since the 1700’s and will continue to pop up throughout the country. With careful planning and regular maintenance, there is no reason why home and business owners cannot continue to enjoy their flat roof for centuries to come. If you need a roof replacement or installation give Crown Remodeling a call today!