Flat roof with skylight and hydro insulation membranes
Custom copper roofing design elevated over luxury las vegas home

We’re all familiar with flat roofs, which are found on all types of buildings. But, is a flat roof the right choice for your building? Flat roofs are different from the more decorative sloped roofs found on homes and small buildings, but they have a lot of advantages in particular situations and may be the right solution for a new building. When a flat roof is the right choice, or when replacing an old flat roof, there are different types of flat roofing materials available to meet the needs of building owners and managers.

Why Flat Roofs?

Flat roof with skylight and hydro insulation membranes

Flat roofs have a number of advantages that make them the best choice for specific types of buildings.  Larger buildings and ones that need to have regular activity on the rooftop are ideal for flat roofs that are lighter, generally less costly to install and provide easy access.

One important factor to understand is that flat roofs are not completely flat. They are usually slightly sloped to allow for precipitation to drain off. Still, with drainage slower than on a higher slope roof, most flat roofs have to be regularly maintained in order to be sure that the roof material is kept watertight and sealed to prevent leaks and damage to the building below. Flat roofs should have a thorough annual inspection to look for problems and reseal surfaces damaged by UV rays or moisture.

Commercial Flat Roofs

Flat roofs are familiar to most of us on commercial buildings where convenience, accessibility, safety and cost are factors in choosing a flat roof solution. Most flat roof materials are lighter and less expensive than the materials used on more decorative sloped roofs. For large buildings, flat roofing is a much more practical solution, avoiding excessive weight on the building’s frame, and also lowering construction costs. Industrial, warehouse, retail, hotels and similar commercial buildings often have multiple HVAC and other systems installed on the roof where maintenance personnel must have quick access, day or night. Having a flat roof makes it much easier to access these roof elements for maintenance and repairs.  Air conditioners and other systems may be placed on the roof, saving valuable space within the building. And, for roofers and other workers accessing the roof, a flat roof means less chance of worker injury from a slip on a sloped roof.

High Rise Buildings

built up high rise flat roof with garden and tiled walkways
sky garden on rooftop of condominium with blue sky

Of course, flat roofs are also commonly used for high rise residential and office buildings in urban settings, where service access is also important. And, from a design and space optimization point of view, urban building roof space is cherished as outdoor space where occupants and guests enjoy access to sunlight and fresh air. High rise apartments, condos and hotels may even build out their roofs to include rooftop gardens, adding attractive lighting, eating areas and even areas for sports activities or a swimming pool. With a flat roof, design options are only limited by the imagination.

Flat roofs are also found in single family homes and other small buildings where climate, style, design and budget make them the right option. They tend to be most practical in areas like the dry southwest where there will be little rain and no snow load for the roof to handle. Flat roofs may be part of a green energy efficient home solution, with accommodation for solar panels or a green roof covered in living plants.

Top 4 Flat Roof Materials

Now that we know where a flat roof makes sense, let’s examine the differences between the four types of flat roofs that are commonly used.

PVC Membrane

PVC flat roof installation with roofer in hard hat cutting the PVC waterproofing material
Waterproofing and insulation at construction site waterproofing membrane preventing water penetration. Exterior vapor barrier for foundations and basements.

Both flexible and easily-customizable, a PVC membrane flat roof is constructed from what is known as a scrim, which is basically a flexible, heavy duty, non-woven polyester fabric that creates a bonded seal and is also fire retardant. The scrim is laminated in a UV-resistant PVC thermoplastic.

Lightweight in nature, a PVC roof will not add weight to the existing structure. As a result, PVC can be installed directly over an existing system. This means there is less material that needs to be dumped into a landfill.

PVC roofing is durable and highly reliable. It has the ability to resist high temperatures, dirt and strong winds.

Built-Up Roof (BUR)

Tar and grvel built up flat roof with skylights and HVAC systems
Flat Roof With Gravel and Skylight Windoows

The Built-up Roof, or (BUR) is a roof made essentially of hot tar and gravel. Layers of hot tar are applied between at least 3 layers of waterproof ply sheets. On top of this, a layer of smooth river stones or gravel are applied.

Ideal for commercial buildings, the biggest advantage of a BUR roof is that it is very affordable. Another plus is that a BUR roof is able to meet higher fire ratings than other roofing materials, as gravel is naturally fire-retardant.

Unfortunately, there are drawbacks to a BUR flat roof. The first is the telltale smell of asphalt, which many find undesirable. Messy to install, a BUR roof is also very difficult to remove. Tar and gravel make this type of roof very heavy in nature, which will put extra stress on the structure of a building.

Rubber Membrane

Historically popular, a rubber membrane, also known as EPDM, flat roof is both durable and lightweight. However, it should be noted that EPDM tends to be less puncture resistant than PVC. With that being said, the recyclability of both options is about the same.

One disadvantage of using a rubber membrane roof in a warmer climate is that it is naturally dark in color, making this choice more prone to absorbing heat.

TPO Roof

TPO (Thermoplastic Polyolefinis) is a blend of two different types of rubber. It is white in color, giving it an energy saving advantage as it reflects sunlight. This translates into dollars saved in cooling costs.

Very easy to install, a TPO roof can either be fully adhered or mechanically-attached to the deck of a roof. Extremely flexible, TPO’s versatility surpasses other roofing materials, without it losing its durability.

Low Slope Metal Roofing

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For beauty, quality and design, none of these choices can approach metal roofing, a durable and decorative alternative to traditional flat roof materials. Metal roofing is highly durable and needs little maintenance. The beauty of copper, zinc and aluminum roofs is undeniable, and they all are highly weather resistant. They are also energy efficient, reflecting the rays of the sun for a cooler interior, and of course they are recyclable. Metal roofs are popular on homes and business looking to increase the beauty and value of the property. Metal can be formed into shapes to create unique, custom and beautiful roofs, roofing or standalone fixtures, overhangs, gutters and other elements that make your home stand out from the crowd.

Prestige Offers Flat Roofing in Las Vegas

No matter which type of flat or other roof you are considering, don’t trust just anyone to do the work for you. Find a reliable and trained professional roofer to help make sure your new roof is the right one for your building, and that it is installed correctly using the right materials to avoid costly damage down the road. For the best residential and commercial roofing services in Las Vegas, contact Prestige Roofing today for a free estimate.