Pricing Guide Flat Roof Cost in San Antonio (2025)
Whether it's a commercial building, multifamily property, or residential addition, here's what flat roofing costs in the San Antonio market.
Get Free Estimate(210) 272-7272 Licensed, Bonded & Insured Transparent Pricing 200+ 5-Star Reviews Free Estimates Flat and low-slope roofs require different materials and techniques than sloped residential roofs. The most common flat roofing systems in San Antonio are TPO (thermoplastic polyolefin), modified bitumen, and elastomeric roof coatings. Each has different cost points, lifespans, and ideal use cases. This guide covers pricing for the San Antonio market.
Quick Cost Overview
Budget
$4,000
Average Range
$8,000 - $18,000
Premium
$50,000+
varies by roof size and system. Residential flat sections are on the lower end. Large commercial projects are on the higher end.
What Affects the Cost?
Every project is unique. These are the main variables that determine your final price.
1 Roofing System
TPO is the most popular commercial option. Modified bitumen is a tried-and-true multi-layer system. Roof coatings can extend an existing flat roof's life at lower cost. EPDM (rubber) and PVC are also options.
2 Roof Size
Commercial flat roofs are priced per square foot. A 5,000 sq ft commercial roof costs significantly more than a 500 sq ft residential flat section. Volume discounts apply on larger projects.
3 Insulation & Energy Code
Texas energy codes may require adding insulation during a flat roof replacement. Polyiso insulation boards add $1 to $3 per square foot but improve energy efficiency and meet code requirements.
4 Drainage & Penetrations
Proper drainage is critical for flat roofs. Adding or modifying drains, scuppers, or tapered insulation for positive drainage affects cost. Each HVAC unit, vent, and curb requires custom flashing.
Cost by Flat Roof System
TPO membrane (60 mil to 80 mil): $6 to $12 per square foot installed. Modified bitumen (2-3 ply): $5 to $10 per square foot installed. EPDM rubber membrane: $5 to $9 per square foot installed. PVC membrane: $7 to $14 per square foot installed. Elastomeric roof coating (over existing): $3 to $6 per square foot installed. Spray polyurethane foam (SPF): $5 to $10 per square foot installed. All prices include materials, labor, and standard accessories for San Antonio.
Coating vs. Replacement
If your existing flat roof is structurally sound with no major leaks, a roof coating can extend its life by 10 to 20 years at 30% to 50% of the cost of full replacement. Silicone coatings are best for ponding water areas. Acrylic coatings are more affordable but less durable in standing water. A coating is not a fix for a failing roof; it's a maintenance strategy for a roof that's still in decent shape.
Commercial Flat Roof Considerations
Commercial flat roofs in San Antonio have additional cost factors: warranty requirements (20 or 30-year NDL warranties cost more), rooftop HVAC equipment that needs to be worked around, code-required insulation upgrades, and edge metal systems. For properties over 10,000 sq ft, competitive bidding usually brings per-square-foot costs down.
Frequently Asked Questions
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