Roof replacement costs in St. Louis depend on the roof’s size, material, and complexity. Learn how much roof replacement costs in St. Louis and which factors affect the cost.
How Much Does It Cost to Replace a Flat Roof in St. Louis? [2026 Data]
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Cost Insights
Flat roof replacement costs in St. Louis average $4 to $14 per square foot.
Hiring a flat roof replacement pro in St. Louis costs about $130 per hour.
Factor in permit and inspection fees, which start at $44 and $400, respectively.
Flat roof replacement offers a return on investment (ROI) of 50% to 70%.
Flat roof replacement costs in St. Louis, Missouri, average $6,328, with most homeowners paying between $3,400 and $10,233. Missouri’s climate plays a significant role in roofing costs, since heavy precipitation, storms, freeze-thaw cycles, and UV exposure are hard on roofing systems and necessitate durable materials to withstand the elements. In addition to labor rates, roof size and materials have the greatest influence on total project costs.
Flat Roof Replacement Cost Factors
The cost of a flat roof in St. Louis, Missouri, depends on the size of your roof, the materials, the application method, and the site prep.
Size
Calculating the size of your roof can help you estimate the cost of a replacement. For a rough approximation, measure the length of your house's exterior, then multiply it by the width to get the size of your flat roof. Consider adding a small percentage to account for any overhangs.
Here are estimated costs by roof size—but keep in mind that the type of roof you plan on replacing, as well as the material, greatly affect your flat roof replacement cost:
| Roof Size (Sq. Ft.) | Average Cost |
|---|---|
| 1,000 | $6,500–$14,300 |
| 1,500 | $9,850–$21,400 |
| 2,000 | $13,100–$28,500 |
| 2,500 | $16,400–$35,650 |
| 3,000 | $19,700–$42,800 |
Materials
Like traditional sloped roofs, flat roofs offer a multitude of material options. Each has its own cost estimate, advantages, and disadvantages. Many roofing materials look similar, so discuss options with your pro.
Here’s a breakdown of estimated flat roof replacement costs based on material:
| Roof Material | Average Cost per Sq. Ft. | Features |
|---|---|---|
| Fiberglass | $4–$6 | Lasts 25–30 years; not durable |
| Rubber | $4–$13 | Resistant to warm weather and UV rays |
| Thermoplastic polyolefin (TPO) | $4–$14 | Good at handling water pools; single-ply system |
| EPDM | $5–$13 | Made from oil and natural gas byproducts; 10–25-year lifespan |
| Built-up tar | $4–$10 | Fire-resistant; low-maintenance; lasts 30 years |
| Glass-reinforced polyester (GRP) | $4–$6 | Weather-resistant; needs very dry installation; lasts 30 years |
| Modified bitumen | $4–$8 | Fully recyclable; low water-resistance; 10-20-year lifespan |
Roof Type
There are several types of flat roofs, including cold roofs, warm roofs, and green roofs. The type of flat roof will influence the price you pay for a replacement.
Here’s how much flat roof replacement might cost based on roof type:
| Flat Roof Type | Average Cost per Sq. Ft. | Features |
|---|---|---|
| Cold | $4–$9 | Insulation is below the roof deck, typically inside the joists or rafters; a ventilation gap is placed above the insulation; more susceptible to condensation |
| Warm | $6–$11 | Insulation is located on top of the roof deck, above the vapor barrier and below the waterproof membrane; energy-efficient; good moisture control; straightforward installation |
| Inverted | $4–$9 | A type of warm roof with reversed layers, shielding the waterproof membrane from the elements |
| Hybrid | $4–$11 | Insulation is split above and below the roof deck; increased risk of condensation; often used when a full warm roof is not possible |
| Curved | $8–$15 | Low-slope roof that has a gentle curve; has flat roof features but a sloped aesthetic; the slope improves drainage |
| Tapered | $7–$10 | Flat roof with a gentle slope created with tapered insulation boards; the design ensures proper drainage and prevents standing water |
| Green | $10–$35 | Partially or completely covered with vegetation; has layers like a root barrier and drainage system; environmental and economic benefits |
Application Method
The most common application methods for flat roofs are ballasted, fastened, and fully adhered. Here’s how the flat roof application type might influence your cost:
Ballasted roofs: $1.50–$2 per sq. ft.
Fastened attachment method: $2–$3 per sq. ft.
Fully adhered method: $2.75–$3.50 per sq. ft.
Demolition and Prep
Your roofing pro might charge extra for removing the existing roof. This costs about $1 to $5 per square foot, or an average of $1,000 to $1,500 total. Prep involves removing debris, mold, or algae and repairing any damage.
Flat Roof Replacement Pro Costs
The cost to hire a flat roofing pro in St. Louis, Missouri, depends on local labor rates, permit fees, and warranties.
Labor
Roofers charge $3 to $7 per square foot or $130 per hour on average for labor, and a flat roof replacement takes about five days, depending on the size and complexity of the job. Labor rates for local flat roof pros are generally higher in downtown St. Louis, and you can expect prices to be 5% to 15% less for projects outside of the city’s urban core.
Some roofing materials, such as built-up tar, are more time-consuming to install, which will affect the overall labor cost. If you’re quoted a fee based on the total project cost, expect a markup of 40% to 60% of the job.
Permits
Most major roofing projects in St. Louis require a permit. These permits start at around $50, and they increase by $10 per every $1,000 of total construction cost over $3,000. Plan for additional costs in case of demolition permits, permit application extension fees, inspections, and re-inspections.
Inspections
It’s a good idea to hire a professional to conduct a final inspection after the roof has been replaced. This will ensure that the contractor did quality work. Expect to pay between $400 and $1,000 for a certified roofing inspection.
Warranties
New roofs should include manufacturer warranties that cover the roofing materials. If you’re comparing similar materials, prioritize the option with the longest and most comprehensive warranty. You can also check online reviews or ask the contractor for clarification.
Does a Flat Roof Increase Home Value?
Replacing a flat roof generally offers strong return on investment (ROI) potential by improving structural protection and overall curb appeal, allowing homeowners to recoup between 50% and 70% of their total flat roof cost. In St. Louis, where heavy precipitation, storms, and UV exposure can stress roofing systems, buyers see recently installed and well-maintained roofs as a major advantage when considering properties.
Modern flat roofing systems also improve efficiency and functionality. Reflective materials can reduce cooling costs during St. Louis’ hot summers, while new, durable materials offer greater resistance to ponding water and weather exposure than aging or damaged roofs.
How Angi Gets Its Cost Data
Home is the most important place on earth, which is why Angi has helped more than 150 million homeowners transform their houses into homes they adore. To help homeowners with their next project, Angi provides readers with the most accurate cost data and upholds strict editorial standards. We survey real Angi customers about their project costs to develop the pricing data you see, so you can make the best decisions for you and your home. We pair this data with research from reputable sources, including the U.S. Bureau of Labor Statistics, academic journals, market studies, and interviews with industry experts—all to ensure our prices reflect real-world projects.
Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.
Roofing services reviews from real Angi homeowners in Saint Louis, MO
4.3★ avg. • 903 total reviews
- Valerie L.
Scott Hill and his crew replace our tile roof with Brava PVC tile (50 year warranty). The work was coordinated and executed with precision. They did the entire job in about 8 days. Excellent job.
Sunrise Roofing STL - Bruce T.
Michael SalazarII did anexcellant job of checking my roof and explaining what needed to be done. He showed me drone pictures of the condition of the roof and what was on top of it. 3938 Labadie Ave. St. louis, Mo. 63107-2115
ECI: A Missouri Exterior Co. - Slaighter C.
I had several roofing issues on both my home and my shop building, and multiple companies told me they were unwilling to take on the challenges involved. Jake and his crew stepped up without hesitation, provided a very competitive price, and delivered workmanship that exceeded my...
Reign Roofing and Remodeling - Roger O.
Alexandra called me to set up the appointment, Christopher followed up quickly and had out rood repaired the same and repaired our roof. They sent pictures and followed up after the rain stopped to make sure everything was sealed. Price was competitive.
- Jon F.
Soon purchasing a new home, and knowing Drew at Duke, he’ll be first on my list for any needed roof work. I’m excited to watch this company take off.
Duke Roofing, LLC - C P.
Our roof needed to be replaced following the May 2025 tornado in St Louis. The job in itself was not super complicated, but there were many moving parts including dealing with the insurance, handling solar panels, etc. These guys did an excellent job, and I would work with them again if I had...
Tesson Roofing & Exteriors LLC - Shirley H.
Midtown installed a new roof for me and the crew was awesome. I'm happy with their work and clean-up. Took 1 day!
Midtown Home Improvements, Inc. (St. Louis) - Allie Z.
Within less than a week, Advance Roofing inspected my roof, gave me estimates, and fixed my roof. They were very friendly and p
Advance Roofing - Peaches Z.
Very good company to work with, there professionals in the Flat Roof industry. Very good price and warranty. I’m looking forward to working with them again.
Done Right Roofing - Bill L.
Fantastic, Bob Kings roofing was on time, the crew polite and professional, they cleaned up very well and the roof was beautiful. I could not recommend this company any higher 5 star or I would!!
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