There is one common problem to flat roofs — unlike sloped or pitched roofs, which have shingles that drain off water much like fish scales or duck feathers, flat roofs are perfect breeding grounds for mold, bacteria, and mosquitos. That’s because water from snow in the winter or rain can get stuck on the flat surface of a flat residential roof with no way to drain out. Because these roofs can accumulate moisture and snow, they face unique sets of problems.
Built-Up Roofing (BUR)
BUR membrane systems are the oldest roofing material used these days, going back over 100 years. Also known as “tar and gravel roofs”, they are called “built up” because they are built layer by layer of roofing felt and bitumen, or asphalt. The number of layers is called “plies,” and you can speak to a roofing professional about how many plies you should install on your roof. However, in general, 4-ply is much better than 3-ply.
There are many advantages to having this type of roofing system. It is water-resistant, impact-resistant, extremely durable, resistant to weathering, and is viscoelastic. Viscoelasticity is the ability of a substance to be elastic or viscous when stress is applied to it.
BUR has been one of the most widely-used flat roofing systems because of its reliability and affordability. It’s also one of the most cost-effective roofing systems. It’s less expensive to install, and depending on how many piles (layers) you and your roofer decide to put on, it can have an overall positive effect on your energy costs.
Modified Bitumen Roofing
The next type of roofing system is very similar to BUR and is an asphalt-based roofing system. They are much younger than BUR systems and came around in the 1960s. These types of systems consist of five layers: the insulation, the plies, membranes, adhesive, and surface protections. The insulation helps maintain the temperature stability of your roofing system, and bonding agents keep it waterproof. These roofing systems can also be covered with a protective coating to prevent damage from UV rays and make it more weather-resistant.
One of the benefits of a modified bitumen roofing system is its superior performance and ability to withstand a multitude of weather conditions. It can also be rated as fire-resistant and hail-resistant. If you’re interested in this type of roofing system then you will want to ask your roofing contractor about those additional benefits to protect your roof and home.
Membrane or ‘Single-Ply’ Roofing (such as EPDM)
Derived from oil and natural gas, Ethylene Propylene Diene Monomer, or EPDM, is a very popular type of roofing membrane material. It comes in black and white, so if you’re looking to lower your cooling costs in the summers, then you can opt for the white. Long rubber plies are installed in massive sheets and reinforced at joints to prevent water from getting inside.
Maintaining Your Flat Roof
As mentioned earlier, flat roofs are notorious for collecting water after rainstorms and having drainage issues. It’s important to keep water from pooling. Leaves and debris can get in the way of drains and block water from flowing in gutters. Always check your gutters and drains after storms, and get your flat roof checked annually. Because the flat roof is exposed to the elements it’s important to use the right ceilings and maintenance techniques to ensure your safety.
