Flat Roof Replacement Cost: Basics

Despite technological progress, the roofing contractors still do not use everlasting and indestructible materials. It means that any roof structure, including flat roof replacement cost, will sooner or later require serious repairs or at worst – even a complete replacement.

In the following guide we’ll share with you some tips concerning the importance of financial planning in any roofing repair or replacement projects. What’s more you will learn how to identify the main factors that affect the final estimate.

Flat Roof Replacement Cost

The Cost of Replacing a Flat Roof: An Overview

Flat roofs (roofs with almost zero angles on slope) are really widespread. You can see them on office or commercial properties, multi-apartment buildings, shopping malls, hospitals, warehouses and all sorts of industrial facilities.

Low-slope roofing constructions are less common in the private real estate segment (unlike pitched roofs), but the demand for them is growing over the past years. Why?

You can find dozens of reasons to install a flat roof. And the fist one is that you can find a variety of modern materials such as durable single-ply TPO and PVC membranes, synthetic rubber or polymer roofing decks on the US market. And they are specially designed for flat roofs.

To add, time-tested roofing solutions like modified bitumen and asphalt roofs, old-school built-up roofs (BUR) are still in active use. You will also easily find roofing constructions made of steel, aluminum, copper, natural slate in suburbs with elite real estate.

Each covering mentioned above has a list of advantages, limitations and guaranteed service life. Another important criterion that directly affects your budget in the long run is the expenses of every-year maintenance, seasonal repairing and partial replacing.

variety of roofing materials
variety of roofing materials

Cost to replace flat roof: make all the calculations advance

1. It is strongly recommended to calculate service and material cost for those who plan to replace the old coating with modern materials in advance. Nine times out of ten a complete replacement becomes a financially advantageous investment that will pay for itself in 5-10 years. Especially if the repair estimate of the roof is almost equal to complete replacement.

However, sometimes replacing over a large area is a costly undertaking and you’d better limit yourself to repair or partial replacement.

2. Make all the necessary calculations and financial planning if you are going to build a new roof. Taking into account the expected lifespan of rubber, asphalt, TPO or PVC, as well as average labor costs in your region, you will be able to predict ‘roofing’ expenses in the foreseeable future. Furthermore, since the profitability of the business depends on the cost of maintenance, roofing calculations are important for owners and tenants of commercial real estate.

Sometimes it is more reasonable to overpay and choose modern roofing material (like single-ply membranes) that will not have to be changed for the next 30-40 years. Anyway, if you don’t plan your spending, you may end up choosing technological solutions as well as roofing materials that will hit your wallet dramatically.

roof calculations

3 steps to get the exact cost of replacing or repairing a flat roof

Firstly, do your own calculations. You will find average price tags for various roofing materials according to 2022-2023 data below.

Secondly, use the online calculators. You can find and use them for free on the websites of local roofing companies. Although online services give indicative prices only, they will be useful for further comparison of available options.

Thirdly, contact trusted roofing specialists in your city. As a rule, after checking the roof or the project, roofers make a detailed estimate with all prices and terms. We recommend that you contact several roofing companies in your city and thoroughly compare their estimates. Some roofing contractors offer free estimates without additional conditions.

You may use the same calculation approach if you want to find out flat roof repair cost.

Cost of flat roof replacement: numbers and statistics

The average cost to replace a common flat roof on a private house ranges from $5 to $30 per square foot. This price includes the regular roofing material and the services of roofers for its installation.

In the commercial real estate category, the prices are usually lower. The average cost to replace regular low slope roofs on commercial real estate in the US in 2021-2022 was between $5 and $9 per square foot.

However, note that many commercial objects are many times larger than residential buildings, so the final roof replacement estimate can also be much higher, up to $100.000 for a 10,000-square-foot roof (imagine how much you’ll expect to pay with 500-900 thousand square feet buildings).

Please note that in some cases the cost of replacing a roof can be higher than installing a new roof from scratch. The reason for the additional expense is the need to dismantle the old material, which can be extremely laborious (BUR, modified bitumen, and so on).

Cost of flat roof replacement

The cost of flat roof replacement: 5 factors to keep in mind

  1. Cost and what is more important – the method of installation of new material
  2. Removal and disposal of worn-out roofing material
  3. Area and architectural type of flat roof
  4. The complexity of the discussed project
  5. Pricing policy of contractor

Flat roof replacement cost: 7 popular materials

  • Rubber. Rubber roofing is a well-known material that has been used in the US for decades. Moreover, technology is constantly being improved. Modern synthetic rubber coatings are durable, watertight, elastic, with a service life of up to 45-50 years. The cost of replacing a rubber roof ranges from $4 without dismantling to $9 with dismantling of the old material.
  • TPO. This membrane material has been actively used in the category of real estate since 90th. It has its advantages over PVC and ‘traditional rubber roof’. However, it has only been on the market for a very short time so there are no statistics on how long it will last. According to manufacturers, professionally installed TPO roofs last up to 30 years. The expected cost of replacing a TPO in 2023 is $7 per square foot on the average, but usually TPO flat roof costs a bit more.
  • EPDM. This material is believed to be the most demanded in the residential real estate segment with low-slope roofs. EPDM membranes are strong and easy to mount even on large scale roofs. Still they have their own environment and use limitations. Some EPDM roofs can be replaced for $5 per square foot (for low-cost thin membranes), while others will cost up to $15.
  • PVC. This synthetic material is supposed to be one of the most popular and universal single-ply roofing materials across the States. It is really durable and watertight (if installed properly). The average cost to replace a PVC roof is about $7-8.
  • Modified Bitumen. Despite the affordable cost of this technology, replacing a roof with a modified bitumen coating can be problematic due to the time consuming dismantling. Installing a modified bitumen roof from scratch and without additional works costs $6 per square foot avg.
  • BUR. Due to installation features, old BUR roofs are really difficult to remove, so the cost of replacing them can be quite high (choose the material that can be mounted on BUR roofs from above). However, the cost of installing a new BUR roof is relatively low, averaging around $5.
  • Metal roof. Metal is one of the most reliable, stable and long-lived materials used in roofing all over the world. If you protect a metal roof from corrosion and uplifts, it can last 100 years or more. However, the cost of replacing steel and aluminum roofing is high (up to $20-25). Installation and replacement projects of copper flat roof cost even more.

Type and area of the roof

Mostly any roofing contractors you can find in the US offer discounts for large (5000 square feet and more) area roof replacements.

On the other hand, if you want to replace small parts of a roof or extension roofs, garage and terrace roofs, porch and patio roofs, roofing companies may increase the total cost of the replacement project as well. The reason is that even for a small project, they need to deliver material, equipment, and a team of roofers.

The cost of work is also affected by the engineering features of so -called ‘roofing pie’. The type of ‘roofing pie’ depends on the specialization of the building, as well as the climatic features of the region.

Roofs can be cold (non-residential premises or attic), warm (attic room), hybrid and inverted. The type of roof is determined according to thermal insulation and waterproofing (some cold roofs don’t have them at all) as well as on the insulation and waterproofing location.

Long story short, warm roofs are designed in such a way as to maintain a comfortable temperature in the attic depending on where you live. Cold roofs are cheaper. Replacement of a professionally installed warm roof will be definitely more expensive than in the case of a roof without insulation.


1. How much does it cost to replace an old flat roof covering?

According to statistics, homeowners pay 1-2 dollars for a square foot of new roofing material. However, premium solutions (copper, slate) cost 4-8 dollars and higher.

2. How much does it cost to replace a flat roof?

It all depends on individual factors, Such as the complexity of the project, the material and the pricing policy of the roofing company. Some materials, which are supplied in sheets or rolls, are easy and quick to install. Some roofing materials can be laid above old coating without the need for dismantling. If the task is not hard for roofers, they will charge 1-2 dollars per square foot. If dismasting, additional work on roof framing, thermal insulation and waterproofing are required, the cost of the roofing services can rise to $5-7 without taking into account average costs of material.

3. What material to choose for replacement?

Take into consideration the type of building, climatic and weather factors, your budget and preferences. Some materials do a better job of protecting against leaks, some are better resistant to mechanical damage, while others do not heat the house in the summer and do not fade in the sun.

Modern membrane materials are most often chosen for residential real estate. More affordable BUR, modified bitumen and other solutions are more suitable for commercial estate.

4. Repair or partial replacement of an old roof?

As mentioned above, it depends on individual criteria. Such as installed material, area, degree and type of damage. Usually it is unreasonable to replace the entire roof if it is enough to install a small patch on the damaged area. Timely repair definitely costs less than replacement.

Sometimes it is better to overpay for the installation of a new roof, since permanent repairs to a worn-out structure will cost the same or even more. Keep in mind expected costs to install a new roof including the cost of additional works like delivering and dismounting.

5. How to extend the life of the roof?

In order not to replace the roof every 5-10 years, it is necessary to carry out seasonal maintenance and repair minor damage immediately after you find them. Don’t forget that even modern materials have their weaknesses. It can be corrosion (for steel roofs), for some flat roof materials it could be UV rays and mechanical damage. It is important to protect the roof from negative influences at the installation stage and during regular maintenance. In addition, it is recommended to contact local roofers and ask them to inspect and maintain a flat roof several times a year (or once a year if your roof is brand new).

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