Flat roof replacement costs and options in 2023 (2023)

There is a wide variety of flat roofing materials that you can install on your home.

Single ply sheeting, asphalt, metal and modified bitumen flat roofing each have their associated costs, advantages and disadvantages.

Flat roof prices depend on the type of material chosen, the complexity of the project, as well as local labor costs.

When you are ready to install a flat roof,Contact your local professionals for 3-4 free flat roof estimates.

How much do flat roofing materials cost?

The average cost of replacing a 1,500 square foot flat roof. Home ranges from$8.000-11.000, depending on the material used and the complexity of the installation.

Installation prices below are for very basic flat roofs over 1,000 square feet.

Any additionalcost of roof insulationand increased installation complexity increase your overall labor costs.

PVC-Membrane: $6.50 – 7.50 + pro Quadratfuß.

EPDM Rubber: $5.50 - 6.50+ per square foot.

TPO canopy: $6.0 - $7.0 per square foot.

Modified bitumen and rolled asphalt roofing: $5.50 – 6.50+ per square foot.

Spray foam canopy: $4.5 - 7+ per square foot.

You can use oursflat roof calculatorto quickly and accurately estimate the cost of your roof replacement.

Flat roofing material prices per square foot

In general, materials used on flat roofs cost less than those used on pitched roofs.

Cost of EPDM rubber roofing$1.50 per square foot, making it the cheapest single-layer membrane.

Cost of TPO canopy$1.70 per square foot

Cost of PVC roofs$1.90 per square foot

Modified bitumen and rolled asphalt roofs cost$1,30-2,20 pro Quadratfuß, depending on the number of layers.

Tar roofs are extremely rarely installed, must be specially ordered and therefore prices are not readily available.

Spray foam roof costs$1,65 – 2,25 pro Quadratfußfor a 1.5 inch layer of foam.

Note that all prices above are for materials ONLY and do not include insulation.

Install roof shingles$4872 Average price	Install metal roof$10253 Average price	Mount flat roof$8257 Average price
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Types of material for flat roofs

While flat roof materials are rather limited in comparisonPitched roof options, there are still enough products to meet various aesthetic and budgetary needs.

Pro tip:Keep that in mind when it comes down to itflat roof, good insulation plays a key role in ensuring your membrane provides lasting protection from the elements.

Insulating a flat roof can be expensive because high-quality insulation, such as 3-inch Poly Iso hard foam panels, costs money$1.25 per square foot of insulation.

However, it is ideal for installing quality roof insulationavoid many problemsThat cheap, crappy insulation will follow later.

Let's take a look at the most popular materials installed on flat roof homes in the US.

Single-layer roof sheeting

EPDM(ethylene propylene diene monomer),PVC(polyvinyl chloride) andTPO(Thermoplastic Olefin) are the most popular single ply roofing membranes.

Today, these three flat roof membranes are used most frequently in commercial and residential construction. Overall, most architects and builders specify single-ply membranes (EPD, TPO, or PVC) for a flat roof installation.

It is important to know that these single layer membranes are NOT equal in quality and longevity. Each has very different formulations, shelf life specifications, and cost.

Single-layer means that there is only one layer of membrane as a waterproof and weather-resistant surface. All membranes are 6-18 feet wide.

The most commonly used are around 10 feet. Average thickness ranges from 45-90 mils. It is usually recommended to install a membrane that is at least 50 mils thick.

Advantages

– Sun reflective and energy efficient
– Some materials can be recycled
– Durable: High-end membranes last up to 30-40 years
– Systems with hot air welded seams (PVC and TPO) are waterproof
– DIY installations and repairs are possible for EPDM rubber
– Resistant to bad weather: snow, ice, rain, wind, fire
– Can be used as a roof garden or terrace

Disadvantages

– Membranes with seams are prone to leaks (EPDM)
– External penetrations such as pipes, chimneys, HVAC equipment can cause leaks without proper plumbing work
– Require expensive professional installation and equipment (PVC and TPO)
- Can be pierced by a sharp object, falling branches, etc

Built-up flat roofs

Built-up roofs are made using built-up layers of either tar-saturated paper and liquid tar with gravel, asphalt, rolled asphalt, or modified bitumen.

As the roof is installed, more and more layers are added to increase durability and longevity, hence the name 'built up'.

These include: 1. Tar and gravel 2. Modified bitumen 3. Rolled asphalt

All this is considered outdated by modern building standards. They are almost never installed on large commercial properties, but continue to be installed in some residential homes due to their low cost.

You should keep in mind that any type of construction material requires a positive roof pitch (minimum 1/12 inch).

Advantages

– Relatively cheap material and assembly costs
– Very low maintenance
– Resistant to foot traffic, UV rays and punctures

Disadvantages

– Difficult to locate the source of the leak
– Short lifespan of 10-15 years
– Costly repairs that often do not solve the problem
– Very poor energy efficiency
- Not environmentally friendly
– Lacks flexibility in cold temperatures and is not recommended for installations in the northern states
– Harmful vapors and vapors are produced when installing BUR
– Very heavy material that often requires structural reinforcement (BUR).

Pro tip:Although many roofing and home improvement websites list modified bitumen, tar and gravel, and liquid roof coatings as viable flat roofing materials, we personally would not recommend any of these to a homeowner.

Each of them has too many potential problems, difficult to install properly, as well as costly and difficult to repair. In short, they're just not worth the hassle given the plethora of better alternatives.

Spraying/painting flat roofs

There are two main types:

1. Spray foam insulation(Sprayed directly onto the roof membrane and then coated with an acrylic or urethane coating and a layer of gravel/sand.

2. Roof coatings(made for existing roofs and to extend the lifespan by 10-15 years). They are usually installed on single-ply, modified, or low-pitched metal roofs.

Advantages

- Seamless installation
– SPF foam conforms to all roof shapes and sizes, even irregular ones
– Offers good insulation and energy efficiency (high R-value)
– Has no seams, which makes the coating waterproof
– Requires minimal maintenance
– Can be applied to existing roofs, eliminating costly demolition and disposal
– Can last up to 40 years if properly installed

Disadvantages

- Very expensive. For example, silicone coating is one of the most expensive materials you can install
– Complex installation process that requires a lot of technical knowledge. Should only be performed by experienced professionals.
– More potential for system failures due to poor installation and contractor errors
– SPF can only be installed in certain weather conditions (very narrow temperature and humidity range)
– SPF is usually specified for commercial buildings, not for residential buildings
– Spray foam roofs emit noxious fumes during installation

Flat metal roof

It may come as a surprise that there are actually many metal flat roofs. That's becauseMetalis an overall superior material that offers durability in inclement weather and 100% protection against leaks and moisture penetration.

standing seam roofs orcorrugated iron sheetsare the two most popular profiles for installation on a flat roof.

Although metal will be the most expensive of all flat roofing materials, it's worth the investment considering it lasts at least twice as long as most other options and requires no maintenance.

The most popular metals to be installed on flat roofs are aluminum or steel. Aluminum is a more expensive and durable option compared to steel. When choosing between sheet steel, choose thicker metal like Galvalume as it offers better protection.

Keep in mind that if you opt for cheaper corrugated iron sheets with fasteners, you may have to deal with rust and leaks that can occur around the fasteners. But even this type of metal flat roofing lasts much longer than single layer membranes, spray coating or modified bitumen roofing.

In terms of style, a flat metal roof will look best on a modern home or over a three-season porch, garage, or modern home extension.

Durability of flat roofing materials

We will detail the most common issues affecting the durability of a flat roof.

leaks / moisture

The biggest problem with most flat roofs are seams and flashings, because that's where leaks occur.

PVC and TPO are the only two membranes that feature heat-sealed seams that never come loose and therefore don't let moisture in.

Tar and gravel, modified bitumen and rolled asphalt offer extremely poor protection against leaks and puddle water.

EPDM rubber typically fails at roof penetrations, fillets and seams, allowing moisture to penetrate.

One of the biggest problems with spray roofs is that the insulation can be eaten by birds, which also causes leaks.

puncture resistance

Built-up roofs are typically 0.5+ inches thick, are made of hard materials, and are therefore very difficult to pierce.

Single ply and spray foam roofing are generally easily punctured by direct contact with a sharp object.

Some PVC materials are equipped with a glass fiber reinforced scrim which makes piercing very difficult.

Keep in mind that increasing the width of a single ply membrane will NOT increase its ability to protect against leaks, but may increase its overall life and make it more puncture resistant.

What is the best flat roofing material?

There is a lot of competition between TPO and PVC roofing membranes and a heated debate about which is better.

Today,PVC canopyis considered to be the most durable.

It is specifically designed to remain intact in a wide range of adverse weather conditions (rain, snow, wind, sun, hot and cold temperature changes).

Another thing that makes PVC so strong is that the top and bottom layers of the membrane are almost the same thickness.

Compare,TPO canopyhas questionable durability as there is no consistent formula among manufacturers experimenting with making it as durable but also cheaper than PVC.

As with any product, we all know what happens when you try to lower prices by lowering the quality of materials.

One factor that affects the strength of TPO is the fact that the top layer (weather resistant surface) of the membrane (which ensures durability) is actually thinner than the bottom layer. For most products, the ratio is 40/60.

Finally, most TPO roofs offer poor resistance to heat and sun overload.

Published:12 January 2023