A Comprehensive Guide to Residential Flat Roofs

flat roof repair

In this guide, we'll discuss...


Flat Roof Systems

There are several flat roofing systems available to homeowners. EPDM—or rubber roofing—is far and away the most popular choice. Advancements in flat roofing technology have brought on other viable options for consumers, including SPF and TPO flat roofing materials.

Here’s a quick look at some of the most popular flat roof systems available in today’s roofing market:

EPDM

Constructed from ethylene and propylene, EPDM is referred to as a thermoset membrane type of roofing, meaning it’s a vulcanized (cured) material. EPDM is a thin, rubber-like material available in rolls up to 50 feet wide. It’s attached to the roof one of three ways: mechanically fastened (screws/nails), ballasted, or glued. EPDM is available in black or white. A white roof is also known as a "cool roof" because it reflects the sun’s rays, reducing the heat absorbed by the sun.

Modified Bitumen (MB)

This type of flat roofing material has been used in the U.S. since the 1970s. It’s similar in appearance to EPDM rubber roofing. However, EPDM is a single-ply installation, while MB flat roofing typically consists of multiple layers. A hot or cold adhesive bonds the layers together. Usually, a weather-resistant MB cap sheet is applied on top of the layers for added protection against the elements.

PVC & TPO

PVC and TPO flat roofing materials make up a class of roofing known as "thermoplastic membranes." Although PVC and TPO look very similar to EPDM, thermoplastic roofing membranes are able to be repeatedly heated and cooled to seal cracks and repair seams, which offers an advantage over thermoset membranes, like EPDM.

Built-up Roofing (BUR)

Once exclusively referred to as “tar and gravel” roofs, built-up roofing technology has advanced quite a bit in recent years. While the traditional layering of hot tar and organic fabric sheets is still in use, modern BUR technology utilizes stronger fiberglass sheets bonded together with layers of cold adhesive, making it safer for workers and people in the area. Oftentimes, built-up roofs are ballasted with river rock or gravel, as shown below.

Built up flat roof with gravel

Spray Polyurethane Foam (SPF)

An SPF roofing system is applied to the roof deck via a spray gun. The foam hardens to form a rigid, durable roof surface. One advantage of SPF flat roofing systems is the ability to add various components to the foam mixture in order to increase UV reflectability and durability. While SPF is an affordable choice upfront, new layers of foam must be applied every few years to maintain the performance of the roof.

Structural Metal Panels

Metal is strong and has hydrostatic (water barrier) characteristics. Structural metal paneling, such as standing seam metal roofing, provides watertight protection against the elements due to the fact that the seams between panels are raised above the roof surface. Metal roofing typically costs three to four times more than other types of flat roofing, although it’s expected to last longer.


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Flat Roof Installation Considerations

A roof is only as good as its installation. That’s why it’s important to factor in durability and the expected lifespan of a particular type of flat roof rather than just choose a roofing material based upon its price tag. Talk to your roofing contractor about the best choice for flat roofing in your area.

Your area’s climate, proximity to the ocean (salt spray), and overall air quality are important to consider when choosing the optimal roof covering.

By choosing the ideal roof based on these and other factors, you’ll ensure maximum roof performance. This will also help save money on repairs and roof replacements down the road.

Most types of flat roofing can provide 10 to 20 years of leak-free performance when properly maintained. So, in addition to choosing the optimal roof covering, it’s also important to have a maintenance plan in place to keep it performing in tip-top shape. It’s not difficult to maintain a flat roof, and primarily involves just keeping it clear from tree debris, heavy snow, and standing water.
 

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Cost of Flat Roofing

The factors influencing the total cost of installing a new flat roof include the type, amount, complexity of the roof, geographic location and number of layers to be torn off the existing roof. Here’s a quick guide showing the average price per square foot for materials and installation of various types of flat roofing.

Flat Roofing Costs by Type
Type of Flat Roofing Cost per Square Foot
(Materials & Installation)
Built-up Roofing (BUR) $2.70 - $4.70
EPDM & TPO $2.10 - $3.20
SPF $0.85 - $1.26
Modified Bitumen (MB) $1.10 - $1.80
Standing Seam Metal Paneling $6.75 - $9.60
NOTE: This pricing guide is a rough estimate only. The exact cost of your flat roofing project can vary significantly based on the factors mentioned above. Contact a local roofing contractor in your area for an accurate quote.
 

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Flat Roof Repairs

Flat roofing takes a beating compared to steep-sloped roofs. Why? Because rainwater, snow, hail, and tree debris doesn’t slide off the roof.

A flat roof takes the full brunt of what weather has to offer. Standing water is a major concern on flat roofs, and it’s something that should be addressed right away when noticed.

Flat roof repairs on EPDM, TPO, and PVC membrane roofs are relatively easy and inexpensive. An experienced flat roof repair contractor can apply watertight patching to EPDM roofs. TPO/PVC roof cracks and small punctures may be able to be heat welded to repair the damage.

A poorly installed flat roof is prone to leaking caused by water ponding, cracking, and blistering. Flat roof leaks are repairable when detected early. Small cracks, standing water, and blisters should be repaired immediately to prevent major leaks and damage to the roof’s substructure.

Basic roof maintenance can help avoid roof repairs altogether. Keep the roof clean of heavy snow, tree limbs, pine needles, bird droppings, and standing water. Follow the roofing contractor’s recommended maintenance plan to maximize the life of the roof.

LEARN MORE: Residential Flat Roof Repair


Hiring a Flat Roof Contractor

At Hometown, we pride ourselves on making it simple to find a flat roof contractor specializing in residential installations, repairs, or replacements. We verify roofing contractor credentials, like licenses and insurance. Hometown also gathers real reviews from verified customers, so you can ensure they meet high standards regarding customer service and quality workmanship.

Depending on the size and cost of the job, it's often best to contact more than one roofing contractor before hiring. Getting multiple roofing estimates isn't typically necessary for small repairs, but it makes sense for complete replacements. Not only can you ensure you're getting a fair price, but you can get a second (or third) opinion on which type of flat roofing would work best for your specific project.