Flat Roof Replacement: Cost Factors, Lifespan, and Money-Saving Tips

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By Ethan Smith

Updated: Sep 25, 2024

8 min read

Flat Roof Replacement
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    Installing the best roof is challenging because the cost of maintenance, repair and replacement depends on the type of roof installed in your house. Roofs also affect the curb appeal of the exterior homes, leaving the first visual impact on the visitors or anyone passing through the property and adding value to the property if you plan to sell it. Several factors affect the flat roof replacement cost, such as the roof's material, the type of roof, whether it's commercial or residential, and many more, which will be discussed later in this article. If you want to know more about the flat roof replacement, here is the detailed information.

    Know More About Flat Roof Replacement

    Flat roofs are mostly preferred for commercial buildings and, at times, for residential homes. The replacement cost is between $3200 and $10600. However, many homeowners prefer flat roofs over pitched roofs because of low labor and material costs, high energy efficiency and cost-effectiveness. Another fact about the flat roof is that its lifespan is less than that of the pitched roof.

    If you plan to replace the roof, the best way is to hire a professional as they do the work better and safer. Roofing material is heavy and needs a team to install it safely, though they charge $3-$7 per square foot, which is justifiable. Some benefits of hiring a roofing expert are that they have the necessary equipment to install the roofs, the expertise to identify the spots not visible to homeowners, and knowledge about building permits, insurance, and warranties.

    What is the Lifespan of a Flat Roof?

    The flat roof lasts 20-25 years if properly installed and maintained. It also depends on the material and the local climate where you stay. For example, a fiberglass roof may last up to 20 years, while zinc roofs last between 60-100 years. If roofs have reached the threshold and show signs mentioned in this article, the roof needs replacement.

    An Early Sign That the Roof Needs Replacement

    the Roof Needs Replacement
    Photo: @rp_flat

    Flat roofs are more vulnerable to leakage than pitched roofs because the scope of water rolling off is less due to its flat surface. The water accumulates on the roof until it naturally evaporates, which gives water enough time to find its way into the roof's surface. Some of the early signs of the leaky roof are discussed below:

    • Stains on the ceiling walls and water damage
    • Water drips from the roof, but the source does not sink
    • Bubbling paint
    • Visible tears and holes
    • Loose flashing on the roof
    • Water spots on the ceiling 
    • Loose membrane
    • Crack in the roof coating
    • Loose fasteners
    • Mildew on the ceilings

    Early identification of the problem helps you save heavy repair or replacement costs, as timely minor repairs add life to the flat roof.

    Points to Consider When Replacing the Flat Roof

    The primary thing to consider is proper research about different roof types, their advantages and disadvantages, the weather conditions in your area, warranties to meet the expenses on unforeseen wear and tear and part of the year when you plan to replace the roof. 

    Factors That Affect the Roof Replacement Cost

    There are multiple factors affecting the cost of replacing a flat roof, such as the roof's material, the roof's size, etc. Let's know more about the factors:

    Roof's Material

    Roofing material is vital in deciding the cost of flat roof replacement. The material quality, durability, and ease or complexity of installation affect the replacement cost. For example, the installation cost of fiberglass is less than that of metal roofs. The different roofing material and its cost of installation is given in the table below:

    Roofing Material Average Cost of Installation
    Fiberglass $5 per sq ft
    Polyurethane $6 per sq ft
    Single-ply membrane $6 per sq ft
    Concrete $6 per sq ft
    Modified bitumen $6 per sq ft
    Built-up tar $7 per sq ft
    Rubber roofing $9 per sq ft
    TPO $9 per sq ft
    Metal $7 per sq ft

    The Roof's Size and Its Complexity of Features

    Size And Complexity
    Photo: @eversealroofing

    The size of the roof also affects the replacement cost. A bigger roof costs more to replace because the cost of material, labor, and time is higher. Similarly, roofs with intricate architectural detailing require more labor to accomplish the task, adding up to cost.

    Ripping and Disposing of the Old Roof

    The charges depend on the layers of the roof and the complexity, as well as on contractors. Many contractors charge $3 -$7 as labor cost, including the ripping cost, whereas other contractors charge it separately. If the existing roofing structure can support the weight of the extra layer, ask your contractor to overlay the existing roof rather than ripping off the old one.

    Quality of Insulation and Underlayment

    The type and quality of insulation impact the cost of flat roof replacement. Premium-quality insulation, such as rigid foam, is costlier than the average material. 

    Warranty Period

    An extended warranty period protects your investment, though it adds to the overall installation cost.

    Geographical Location

    The regulatory requirement in your area affects the cost of replacement. In areas where material procurement is difficult, you may have to bear extra shipping costs. 

    Drainage System

    Shifting the drainage system to the roof may cost $600-$1000, but this is inevitable because drainage ensures that water doesn't run down the sides of the home, damaging the structure.

    Application of Sealant

    Another factor adding to the cost is sealant, which is used to seal the top layer of the roof to block water from entering the indoor house. The sealant cost is between $50 and $500; if you have a chimney or vent, you may have to bear an additional cost of $500-$1000.

    How Do We Minimize the Flat Roof Replacement Cost?

    Flat Roof Replacement Cost
    AI Generated Image: Dwellect

    Here are the ways to control the roof replacement cost:

    • Ask for quotes from three to four contractors with expertise in flat roof installation. It ensures you can compare the costs and decide whom to give the order to.
    • If the existing roof can bear the weight of the new roof and is in good condition, don't rip off the old roof. Rather, install the new one over the old roof. It will save on ripping and disposal costs.
    • Opt for the best quality material to save on frequent repair and maintenance costs.
    • Inspect the roof regularly and keep the roof's surface clean.
    • Start the installation work during the off-season.

    Conclusion

    Flat roof replacement requires proper research about the various components affecting the installation cost, such as the roof material, geographical location and others discussed in the article. All the above information will help you calculate the approximate replacement cost.

    FAQs

    How Long Do Flat Roofs Usually Last?

    The lifespan of a flat roof depends on the material and the level of maintenance. Metal roofs may last longer than asphalt roofs.

    Are Flat Roofs Cheaper to Replace?

    Flat roofs are comparatively cheaper to replace as they cover a small area.

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