Professional Flat Roof Replacement

Trust Odyssey Roofing With Your Flat Roof Replacement.

Flat Roofs Are Everywhere – But What About Homes?

Flat roofs are a common sight throughout Illinois, Indiana, and Wisconsin. Flat roofing is a type of roofing system that is characterized by its low-slope design, and is typically used on commercial and industrial buildings – but is also not uncommon to see on residential homes. This type of roofing is designed to provide a sturdy, weather-resistant surface that can withstand heavy loads and provide long-lasting protection to the building.  Most flat roofs you have seen are probably on commercial buildings – such as warehouses, malls, or department stores. These buildings, usually retail or wholesale locations, utilize flat roofing to maximize the available space of the building. Even so, there are plenty of residential homes with flat roofing that require either complete flat roof replacement or partial flat roof replacement.

Though replacing a flat roof may seem to be easier than installing shingles on a pitched roof, flat roof replacement actually requires much more focus and attention to detail. This is because flat roofs need to be completely water proof, and must be adhered in a way that allows that to happen – which requires properly sealing potential water entry points with copping and building up the roof with insulation board and ply-base. Whether choosing a roof design for a new home or replacing a current flat roof, Odyssey offers much of the information needed to make informed decisions for a lasting, sturdy roof cover for your investment. Explore the following guide to answer many of your flat roof-related questions.

Flat Roofs Are Not Flat

A flat roof, also known as a low slope roof, may look flat at first sight – however, it is essential that a flat roof is not actually flat. Flat roofs, when done correctly, should have a slope of at least 1/4 inches per foot. Unlike pitched roofs with some form of roofing shingles and a pitch of 2 inches per foot or more, flat roofs cannot easily and quickly shed water but require much more time for water to be drained out. For this reason, flat roofs must not only be thoroughly water tight but must also be built to have a small incline for water to drain out properly – the worst thing for the lifespan of a flat roof is for water to sit in pools for longer than 48 hours.

Flat Roof Replacement Cost: How Much Does It Cost to Install A Flat Roof?

Flat roofs are a common sight on commercial and residential properties, and many people have the misperception that a flat roof replacement will cost less than their shingled counterparts – mainly due to assuming that labor costs will be less because installation crews do not have to install on an incline. This could not be further from the truth, as flat roofs are both more labor intensive and require more costly materials than asphalt shingle roof replacement projects. In this section, we’ll take a closer look at the cost of replacing a flat roof and the best replacement options available.

Cost of Replacing a Flat Roof

The cost of replacing a flat roof can vary greatly depending on several factors, including the size of the roof, the type of roofing material used, and the complexity of the installation process. On average, the cost of replacing a flat roof that does not need any extra woodwork or tapering will range anywhere from $8,000 to $12,000 for a 1,000 square foot flat roof. Here’s a breakdown of the average cost of some of the most popular types of flat roofing materials per square foot:

  • Modified Bitumen ($8 to $13)
  • TPO ($8 to $15)
  • EPDM ($12 to $16)
  • BUR ($10 to $15)
  • Spray-Applied Coatings ($3 to $6)

Factors that Affect the Cost of a Flat Roof Replacement

Here are some of the main factors that can affect the cost of replacing a flat roof:

  1. Type of Flat Roofing Material: The type of material used for a flat roof replacement can greatly affect the overall cost. A properly installed flat roof system will include insulation board, a plybase, and cap sheet (what people might call the “rubber roof” or the visible membrane). The best type of flat roofing for cost effectiveness and longevity – and what we install at Odyssey Roofing – is a 3-Ply Modified Bitumen system. Other common types of flat roofing on the market are EPDM, TPO, and built-up roofing. The cost of flat roofing materials can range from $4 to $8 per square foot depending on how much insulation board is installed underneath and if metal copping is needed.

  2. Flat Roofing Installation: The installation of the roof will also affect the cost of a flat roof replacement, and can range anywhere from $4 to $6 per square foot. Additional costs may be incurred if the installation requires replacement of rotted wood, removal and disposal of extra layers of old roofing, tapering, or copping along parapet walls. These add on costs, if not already included in the contract price, could add anywhere from $2 a square foot for extra layer removal to $20 per square foot if tapering is needed. Luckily, a professional flat roofing contractor will be able to determine if you need most of these before hand, such as copping and tapering. It is extremely difficult to tell if you will need wood decking replacement before the roof is removed, however. 

  3. All In Labor and Installation Cost: The cost of labor and material for a flat roof replacement, including removal and disposal fees, can range anywhere from $8 to $30 a square foot depending on many of the factors listed above. For a straightforward flat roof replacement with no rotted wood, no extra layers, and no tapering involved, you can expect to pay between $8 and $12 a square foot. 

Options for Flat Roof Replacement

If you’re considering a flat roof replacement, here are some of the options available:

  1. Modified Bitumen: Rolled on using a blowtorch that secures the roofing material, modified bitumen is a cost-effective, energy-efficient, and quick option to install. However, it can also be dangerous to install and may require one of our many trained and certified professional crews at Odyssey Roofing

  2. Built-Up Roof: Made of tar and gravel, built-up flat roofs (BURs) are a popular option because they’re an efficient insulator, durable with many layers, and aesthetically pleasing. However, the layers make the roof very heavy, and extra roof support may be required. Homeowners are not recommended to be present during installation, as the process can be dangerous.

  3. EPDM and TPO: Ethylene propylene diene monomer (EPDM) is a type of synthetic rubber roofing made from a mixture of recycled materials that are durable, easy to install, and inexpensive. Opt for spray-applied EPDM roofing to avoid the risk of seams pulling away from the roof during a seaming installation. Thermoplastic polyolefin (TPO) is another term for this type of roofing.

  4. Spray-Applied Coatings: Seal and protect your flat roof from water damage with a spray-applied coating. While the application process can be tedious, when sprayed correctly, it can increase the life expectancy of your flat roof.

Flintlastic SA Flat Roofing

Resawn Shake

Flintlastic GTA Flat Roofing


Flintlastic GTA Flat Roofing


Flintlastic SA Flat Roofing

Colonial Slate

Modified Bitumen and Advanced Roofing Systems

Modified bitumen roofing is a type of flat roofing system that is made from asphalt and various reinforcement materials, including polyester, fiberglass, and other composites. This roofing system is designed to provide long-lasting protection to a building and is ideal for use on low-slope or flat roofs. The asphalt used in modified bitumen roofing is formulated to withstand the elements, including rain, snow, wind, and UV radiation, making it an ideal choice for harsh climates.

Advantages of Modified Bitumen Flat Roofing

  • Cost-effective: Modified Bitumen flat roofing is gives more value than other types of flat roofing. It requires no specialized equipment to install and has the longest warranties, making it an ideal choice for budget-conscious building owners.
  • Low-Maintenance: Requires minimal maintenance and is designed to last for many years with proper care.
  • Versatile: Flat roofing can be installed on a variety of roof structures, including concrete, metal, and wood.
  • Waterproof: Modified Bitumen flat roofing is designed to completely prevent water infiltration, making it ideal for areas with heavy rainfall.
  • UV Resistant: Modified Bitumen flat roofing contains a cap sheet that is UV-resistant, unlike other flat roofing installations that are susceptible to damage from the sun’s rays.

3-Ply Flat Roofing Systems - Self Adhered and Torch Down

Composed of asphalt and reinforced with either polyester or fiberglass, modified bitumen roofs blend traditional and modern roofing technologies. Two different polymers, Styrene Butadiene Styrene (SBS) or Atactic Polypropylene (APP), modify the membrane and impart greater elasticity and temperature flexibility. Since polyester fiberglass fortifies the roof system, it exhibits more strength and resistance to punctures. It is typically installed in various layers to provide a multi-tier protection system from water, extreme temperatures, and wind uplift. 

Self-Adhered and Torch Down flat roofing are two different methods of installing modified bitumen roofing systems on flat or low-slope roofs. Both of these methods have their own unique benefits and drawbacks, and the choice between the two will depend on a number of factors, including the climate, the size and slope of the roof, and aesthetics. Regardless of whether you choose self adhered or torch down flat roofing, all Odyssey Roofing flat roof replacements come with insulation board and ply-base to ensure you have a quality flat roof that will last its full lifespan. 

Self-Adhered Flat Roofing

Self-adhered flat roofing, also known as “modified bitumen self adhered roofing”, is a type of modified bitumen roofing that is installed using a self-adhesive material. The roofing material is coated with a special adhesive that allows it to be easily and securely attached to the roof deck. Self-adhered flat roofing is a popular choice for flat roofs due to its ease of installation, its resistance to water and weather, and the many color options available to its cap sheets.

This type of roofing is installed in multiple layers, with each layer being held together with the self-adhesive material. This allows the roofing system to be installed in a timely manner without requiring an open flame, making it a great option for many homeowners. However self-adhered flat roofing may not be suitable for use in extremely hot climates, as the heat can cause the adhesive to break down over time.

Torch Down Flat Roofing

Torch down flat roofing, also known as “modified bitumen torch down roofing,” is a type of flat roofing system that is made from a heavy-duty, modified bitumen membrane. This type of roofing is installed by heating the membrane with a torch and then adhering it to the roof deck. Torch down roofing is a popular choice for flat roofs due to its durability and long-lasting protection.

Torch down flat roofing is highly resistant to water and weather, making it ideal for use in harsh climates. It is also highly flexible, which allows it to expand and contract with temperature changes without cracking or breaking. This type of roofing is often installed in multiple layers, with each layer being held together with a special adhesive that binds when torched. Torch down flat roofing, while able to withstand extreme temperatures better than Self adhered flat roofing, only comes in black and white colored cap sheets.

3 Ply Flat Roofing System

Flat Roof Installation - Detail, Drainage, Tapering

Thanks to ever-improving waterproof materials and installation techniques, properly installed flat roofing has become a strong option in the more climate-heavy areas of Illinois and Wisconsin. The keyword, however, is properly installed. Flat roofing requires a combination of patience, engineering, and tolerance for hot, hard work that goes beyond what is needed for a typical roofing job. Flat roofs must be built to allow for adequate drainage, a tapering process that many contractors ignore due to the time constraints of their other commitments. At Odyssey Roofing, when we are on the job for your roof replacement, we are on the job for you – we make sure your flat roof is not simply finished quickly but in a manner that allows you to enjoy peace of mind and longevity that modern flat roofing systems offer. Flat roof replacement is a job for expert roofers – for Odyssey roofers.

Self Adhered Flat Roofing Color Choices

Flat Roof Frequently Asked Questions

The lifespan of modified bitumen roofing can vary depending on factors such as the climate, the quality of the roofing materials, and the level of maintenance performed. On average, modified bitumen roofing last between 15 and 25 years with proper care.

Yes, flat roofing can be used on residential homes, as well as commercial and industrial buildings. A professionally installed flat roof can needed insulation to your home and will be low-maintenance.

Yes, modified bitumen roofing can be installed on a variety of roof structures, including concrete, metal, and wood.

The cost of installing flat roofing can vary depending on factors such as the size of the roof, the materials used, and the location of the building. On average, flat roofing installations can cost between $10,000 and $30,000 depending on the number of layers of removal, wood decking replacement, and the amount of insulation board used.

Roof replacement is a big investment, and it is always a good idea to set the proper expectations going into such a project. Learn more about the cost of a flat roof in our recent blog post. 

Yes, proper maintenance of certain areas such as flashings and copping is essential for flat roofing to ensure that it remains in good condition and continues to provide effective protection to the building. 

Flat roof installations that are not full replacement Modified Bitumen, EPDM, or TPO tend to have a much shorter lifespan if they do not receive the proper maintenance. Most of these types of flat roof projects, such as layovers or spray coatings, only carry 1 to 5 year warranties.

When attempting to repair a flat roof, you can use adhesive patches if it’s made of rubber and synthetic membranes. For an asphalt roof, you can use caulk to repair it or bitumen to reseal it. This is a tricky process, however, as flat roofs must be water tight!

Insurance coverage for a flat roof is much trickier than for asphalt shingle roofs. This is because most flat roofs were not installed with modern technologies, and insurance companies only cover like-for-like and sometimes code upgrades. For asphalt shingle roofs, code upgrades mean underlayments, ice and water shield, and drip edge – for flat roofing, in most cases a lot of the important accessories that allow your flat roof to last more than 10 years are not in city or state code.

A new roof will increase the value of a home by about $15,000 – $20,000 on average in the Midwest, which is typically close to a 70% return on investment of a roof replacement project. Also, because flat roofing should also come with insulation board, it can also save you a lot of money on monthly energy bills if your insulation was lacking beforehand. 

While EPDM is arguably the longest lasting of flat roofing materials, it is also much more expensive than a 3-ply modified bitumen system and does not last that much longer. At Odyssey Roofing, our CertainTeed Flintlastic GTA modified bitumen 3-ply roofing systems carry the same warranties as EPDM roofing, while our SA flat roofing systems are not far off.

Although there are tons of pros to installing a residential flat roof, there are of course some disadvantages too. Flat roofing material must be seal to be water tight – this process  can be unreliable in cold weather.  The biggest disadvantage of a flat roof is the potential for a lack of drainage, which can only be avoided if your roof replacement contractor is away of the proper way to install flat roofing and tapers it down. Finally, it is imperative that drainage is checked regularly to make sure it is not clogged or else water will pool on your flat roof and have a potential to cause damage if pooling remains more than 48 hours.

Absolutely not – if installed properly! While flat roofs are not able to shed water as quickly as pitched roofs, they are designed to be completely water tight. If a professional flat roofing company installs your flat roof, they should be able to determine its drain points and taper it (if needed) accordingly.

While it is not a problem for your flat roof to have puddles right after a heavy rain, it is a problem if that puddle does not dissipate within 48 hours of the rainfall. If you notice that you have puddles on your flat roof 2-3 days after the last rainfall, that means your flat roof was not tapered properly – this can cause severe damage to the roof deck and even the structural roof trusses and rafters if left too long. Contact the flat roofing professionals at Odyssey Roofing today to get your flat roof replaced right.

The Odyssey Way

We’re with you through every step of the roof replacement process


The first step in your roof replacement project. An Odyssey roofing specialist will go over all the details of your roof replacement, from the installation process to the type of roofing materials used.


After you have chosen the type of roofing materials you would like to use for your roof replacement; your roofing specialist will provide you with the total cost of the project as well as financing options.


Once you start your roof replacement project with Odyssey, our production team will order your roofing materials and handle the logistics. We will also obtain any permits required for your roof replacement- all you have to do now is wait!


When your roof material is manufactured and ready to ship, an Odyssey roofing project manager will contact you to set up a day and time that works for you to begin your roof installation.

See What Our Customers Are Saying About Odyssey Roofing

Andre D
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Wonderful experience working with the Odyssey Roofing team for my roof repair and replacement. Everything from the start of work to completion happened on the timeline that I was promised. I would highly recommend them to friends and family.
Jaclyn C
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The team at Odyssey did an absolutely fantastic job with my roof and siding. They were professional and courteous. From the initial consultation to the final inspection, they went above and beyond to ensure that everything was done just they way that was promised. I will definitely be calling Odyssey Home Remodeling when it is time to replace my windows.
Charity H
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The staff at Odyssey was very helpful and always communicated in a timely fashion. The people at Odyssey are ethical and professional, highly recommend this company, they have done my home, and my mother's home!
Anirudh S
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Very impressed with Odyssey Roofing. Great products, warranty, and service at a very competitive price
Rocco E
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This is a great company! They did the roof on our 4000+ square-foot home in Naperville and also replaced several windows in one project, completing a wonderful new sunroom! And each case offering choices and making informed suggestions we are very pleased with their work, and very competitive prices. Steve Marangos the president is a true professional, who is most pleasant and accommodating to work with. He and his people aim to please and to do things with quality to meet and exceed expectations. He and they are dedicated to doing the job right to please their clients to earn their future business. Their work is on time, and neat as well.. closely a tentative on-time start and completion, and to No mess, thorough cleanup. We are pleased to highly recommend Steve and his team at Odyssey Home Remodeling. Less
Karen C
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We want to thank Steve and his employees. They were very professional and friendly in handling our roofing damage and in a timely manner. I would recommend them for anyone needing repairs. Thank you
Chiquita B
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Odyssey Home Remodeling replaced my roof with designer CertainTeed shingles and copper flashing. They were much less expensive than the prices I was seeing elsewhere for similar work and they did an amazing job from start to finish! I would recommend this company in a heartbeat.
Upcon Group
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They were very responsive and did a great job on the repairs we needed.
chicagokid 340
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I got a bang for my buck. Good quality material. I never had a roof put on before and they made it so easy. I had other contractors, but they couldn’t compare to the deal I got with ODYSSEY home and remodeling. I would definitely recommend them to anybody who is getting the roof done.
S Garcia
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From the first response to completion. The Odyssey team was timely and professional! We will definitely consider them when we replace our windows!
U Peppers
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Joe came to give me an quote today he was very informative and educated me . That i appreciate. I look forward to doing business with this company. Stay tuned for my follow up review
J Bush
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Having a roof replaced is an extremely stressful, expensive experience. Working with Steve at Odyssey Home Remodeling made this endeavor much less stressful. He is very professional, knowledgeable and went out of his way to assist with our time and budget restraints. The roofers, Ivan and his crew, were also very professional and answered any questions we had. I would highly recommend contacting Steve at Odyssey Home Remodeling for home projects.

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