A flat roof, or low-slope roof as it is commonly called in the industry, is any roof with a slight incline. This minimal slope is essential to facilitate rain runoff, preventing water from pooling and causing damage. Despite the name, flat roofs are not completely horizontal but have just enough gradient to aid water drainage efficiently.
What Does Flat Roofs Stand For?
Flat roofs refer to roofing systems with a slope of less than 10 degrees, providing a nearly horizontal surface. Commonly used in commercial buildings and modern residential designs, flat roofs often rely on waterproof membranes to prevent water accumulation and leaks, as the low slope can make drainage more challenging than with pitched roofs.
What are the Different Types Of Flat Roofs?
Flat roofing systems are constructed using a variety of materials, each catering to specific needs and climates. Common types include:
- Built-Up Roofing (BUR)
- Modified Bitumen
- EPDM (Ethylene Propylene Diene Monomer)
- TPO (Thermoplastic Olefin)
- PVC (Polyvinyl Chloride)
How Long Have Flat Roofs Been Around?
Flat roofs have been utilized for thousands of years, originating in desert climates such as the Middle East and Northern Africa. As early as 7100 BC, structures in Turkey featured flat roof designs. In North America, Pueblo buildings constructed in the mid-8th century incorporated flat roofs, with Taos Pueblo in New Mexico being a notable example still in use today. Modern flat roofs evolved in the mid-1800s, predominantly for commercial applications, using materials like steel, concrete, and wood.
What Goes Under Flat Roofing System?
Flat roofing systems consist of several layers to ensure durability, insulation, and waterproofing. These layers typically include:
- Roof Deck
- Vapor Barrier
- Insulation
- Adhesive or Bonding Layer
- Roofing Membrane
What Colors Does Flat Roofing Come In?
Flat roofing systems come in a range of colors, each influencing aesthetics and performance. Common options include:
- Black: Traditional for bitumen-based systems.
- White: Popular for energy-efficient membranes like TPO and PVC, reflecting sunlight to reduce heat absorption.
- Gray: A neutral and versatile choice seen in EPDM and TPO.
- Brown: Earthy tones typically found in modified bitumen systems.
- Green: Vegetative roofing options that integrate plants for eco-friendliness.
How Thick Is Flat Roofing?
Flat roofing systems generally range in thickness from 40 to 80 mils (0.04 to 0.08 inches), depending on the material and specific application. Some systems may be thicker when multiple layers are used, but this range is standard for membranes like TPO, PVC, and modified bitumen.
What Is The Life Expectancy Of A Flat Roofing System?
With proper maintenance, flat roofs can last 20-30 years or more. Factors affecting longevity include material quality, installation expertise, and adherence to a regular maintenance schedule.
Is Flat Roofing Hail Resistant?
A flat roof is highly susceptible to hail damage. The three standard types of flat roofing systems are built-up roofing, single-ply membrane and modified bitumen. EPDM rubber roofing systems are hail resistant, but will likely dent during a hailstorm. Large hail could damage the insulation board under the membrane.
How Much Does Flat Roofing Cost?
The cost of installing a flat roof ranges from $3 to $9 per square foot, depending on factors like material choice, roof size, and installation complexity. Additional expenses, such as insulation, labor, and roof removal, may influence the total cost.
