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Roofing Types for Flat Roofs: Understanding Your Options

Roofing Types for Flat Roofs Understanding Your Options


Flat roofs are a popular choice for commercial and industrial buildings due to their practicality, accessibility, and ease of maintenance. However, selecting the right roofing material and system for your flat roof can be challenging due to the variety of options available. This article will discuss the different types of flat roofs and roofing materials, their features, benefits, and drawbacks, and how to choose the best option for your building.

Types of Flat Roofs

Before discussing the various roofing materials available for flat roofs, it is important to understand the different types of flat roofs themselves. Flat roofs are relatively common in commercial and industrial buildings, and they are generally defined as any roof with a slope of 10 degrees or less. Flat roofs are comprised of three basic types:

Roofs that are ballasted

This type of flat roof consists of a waterproof membrane secured to the roof deck with a layer of ballast, typically gravel or pavers. Ballasted roofs are relatively easy to install, require minimal maintenance, and provide excellent insulation. However, they are unsuitable for buildings with heavy foot traffic due to the risk of ballast shifting or dispersing.

Roofs that are mechanically attached

This type of flat roof utilizes screws or other mechanical fasteners to secure the waterproof membrane to the roof deck. Mechanically attached roofs are highly durable and withstand heavy wind loads and foot traffic. However, they can be more expensive to install than ballasted roofs, and the fasteners can create potential leaks over time.

Roofs that are fully adhered

This type of flat roof utilizes an adhesive to bond the waterproof membrane directly to the roof deck. Fully adhered roofs are highly resistant to wind uplift and water infiltration and are suitable for buildings with heavy foot traffic. However, they can be more expensive and time-consuming to install than other flat roofs.

Roofing Materials for Flat Roofs

Once you have determined the type of flat roof best suited for your building, the next step is choosing the appropriate roofing material. The following are some of the most popular types of flat roof materials for different types of roofs:

Modified Bitumen Roof

Modified bitumen roofs comprise multiple layers of asphalt and rubber or plastic modifiers, which provide added durability, flexibility, and UV resistance. Modified bitumen roofs can be installed in various ways, including adhered, mechanically attached, or ballasted.

Single-Ply Membrane

Single-ply membranes are a popular roofing option for flat roofs due to their lightweight, energy efficiency, and ease of installation. They come in various types, including TPO (Thermoplastic Olefin), PVC (Polyvinyl Chloride), and EPDM (Ethylene Propylene Diene Monomer). Single-ply membranes are typically installed by being mechanically attached or fully adhered.

Built-Up Roof

Built-up roofs consist of multiple layers of roofing felt and asphalt that are adhered to create a waterproof membrane. Built-up roofs are highly durable and withstand heavy foot traffic and extreme weather conditions. However, they can be more expensive and time-consuming to install than other flat roofs.

PVC Roof

PVC roofing systems are made of reinforced PVC membranes and are known for their excellent durability and flexibility. PVC roofs are highly resistant to weathering, chemical damage, and fire, making them popular for commercial buildings. They are typically installed by being mechanically attached or fully adhered.

Rubber Roof

Rubber roofs, also known as EPDM (Ethylene Propylene Diene Monomer) roofs, are highly durable, flexible, and resistant to UV radiation and weathering. They are typically installed mechanically attached or fully adhered and are an excellent option for buildings in areas with extreme weather conditions.

TPO Roofing

TPO (Thermoplastic Olefin) roofing is a type of single-ply membrane known for its energy efficiency, resistance to UV radiation and weathering, and ease of installation. TPO roofs are typically installed by being mechanically attached or fully adhered.

Shingle Roof

While shingle roofs are more commonly associated with residential buildings, they can also be used on flat roofs. Shingle roofs are made of asphalt or fiberglass and can provide a cost-effective roofing option for smaller commercial buildings. However, they are not recommended for larger buildings or areas with high wind loads.

Choosing the Best Material for Your Flat Roof

When choosing the best material for your flat roof, several factors must be considered, such as the building’s location, size, usage, and climate. Some of the essential criteria for selecting the right roofing material include:

Durability: Your flat roof must withstand harsh weather conditions, foot traffic, and any other environmental factors unique to your building’s location.

Ease of Installation: The ease of installation of your roofing system will depend on the type of flat roof and roofing material you choose. Make sure to select a material that is easy to install, which will reduce labor costs and installation time.

Cost: The cost of the roofing system will be influenced by the type of material, the roof’s size, and the installation’s complexity. You should select a material that provides the best value for your budget.

Maintenance: Regular flat roof maintenance is essential to extend its lifespan and prevent any significant issues from developing. Choose a roofing material that is easy to maintain and requires minimal upkeep.

Benefits of a Flat Roof

Flat roofs offer several unique benefits that make them a compelling choice for certain buildings and environments. One of the primary advantages of a flat roof is its cost-effectiveness in both construction and maintenance. The simple design requires fewer materials and labor during installation, resulting in lower expenses. Additionally, these roofs provide extra usable space, which can be transformed into rooftop gardens, recreational areas, or even additional storage. Moreover, flat roofs are easier to access and inspect, simplifying maintenance and repairs. Their horizontal surface also allows for the installation of solar panels more efficiently, promoting eco-friendly energy solutions. Overall, the benefits of a flat roof encompass cost savings, versatility, and environmental friendliness, making them a practical option for specific architectural needs.


In conclusion, there are many different types of flat roofs and roofing materials to choose from, each with unique benefits and drawbacks. Before selecting a flat roof system for your commercial building, it’s essential to understand the different types of flat roofs available and the advantages and disadvantages of each roofing material. By considering each option’s durability, ease of installation, cost, and maintenance requirements, you can choose the best material for your flat roof and ensure your building’s longevity and protection. Consulting with a professional roofing company or contractor can also help you make the right decision and ensure that your flat roofing system is installed correctly.

Cedar Shake Roof Cleaning in Des Moines Iowa
Cedar Shake Roof before & after cleaning

Meet Bruce

50 Years of Experience &
Over 2,000 Shake Roofs Cleaned

Bruce Sullivan has over 50 years of experience in maintaining, cleaning, and restoring cedar shake roofs. Making him one of the top authorities on cedar shake roofs in the US.

Watch the Cedar Shakes Cleaning Process in Action in this video

Play Video about Roof Cleaning How to Remove Moss, Lichen, Fungi from a Cedar Roof Sullivan Roof


What can I say? Bruce and Keith provided an exceptional service, and they are really nice guys too. Found out at the last minute they were in Minneapolis, and they fit me in for a cedar shake roof cleaning the next evening after their regular job was done. Even cleaned up my gutters, small fence, and small deck at no charge. The place looks outstanding! Highly recommended.

Mike Richards

I highly recommend this business. Due to the work performed we are going to get another 10-14 years out of our cedar shake roof. We were told by some roofing companies that the roof should be replaced in 2 years. I lucked out and found Sullivan Roof Cleaning while researching companies that perform this service, and was pleased to learn that the company does work outside of Iowa. If you need your cedar shakes cleaned, go with Sullivan Roof Cleaning.

Eric Oelrich, 
St Cloud, MN

Bruce did a great job cleaning the whole exterior of my house. The roof has new life! It looks practically brand new. All the mold and moss on the roof, on the gutters, under the eaves, completely gone. He exceeded all our expectations. When he tells you what he can do for your house, you can believe and trust him. Great guy, great service.

Stuart Malone
Kansas City, MO


Cedar shakes are organic. Though a resilient material. Being organic they need to be maintained. Over time, like any organic material that are subjected to weather elements, they reach a stage of deterioration. Like UV exposure, moisture and seasonal changes. Which results in moss, mold, mildew, lichen and brown rot fungi. These infestations need to be removed to further preserve the integrity of the cedar shake.
The proper way to clean a cedar shake roof is from a ladder. By spraying a special formulated solution onto the shakes and then rinsed with a garden hose pressure. Best done by a professional cedar shake roof cleaner. Not DIY recommended.
No. Pressure washer will require walking on the shakes, which will harm them, and even at its lowest setting will also damage the shakes.
On average, cedar shakes should be cleaned every 10 ten years. Subjective to the grade of the shakes and the amount of surrounding tree cover.
Avoiding walking on a cedar shake roof, other than for repairs.
Never seal a cedar shake roof. Cedar shakes need to breathe. They expand and contract in rain conditions. Seal will shorten the lifespan, to the point of premature replacement.
Staining has no real preserve value and can also harm the integrity of shakes, as stated, they need to be able to breathe. Also, if the shakes are not properly cleaned staining can seal the deteriorating infestation within the shakes.
Depending on the grade of the shakes and installation, and if maintained properly, 40 to 60 years.


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