In this article 14 sections
- Metal Roof or TPO for a Warehouse?
- Comparison Table | Cost, Lifespan, Energy, Maintenance
- What Each Costs on a 30,000 Sq Ft Warehouse
- Roof Slope and Structure | What Decides It?
- Retrofit Options | TPO Over Metal, Coating Over Metal, New Panels
- How a TPO-over-metal retrofit is built
- FAQs | Metal vs TPO
- Can you install TPO over a metal roof?
- Which lasts longer on a warehouse?
- Is a metal roof cooler than TPO?
- Is metal or TPO quieter in rain and hail?
- Which is better for a warehouse I plan to sell in five years?
- What are the disadvantages of TPO on a warehouse?
- Get a Retrofit Assessment
Metal Roof or TPO for a Warehouse?
On an existing metal building, there’s a third path: keeping the structure and retrofitting over it. Here’s how we compare the options when pricing commercial roofing in San Antonio for warehouses.
Comparison Table | Cost, Lifespan, Energy, Maintenance
| TPO | Standing seam metal | |
|---|---|---|
| Installed cost (San Antonio) | $5.28 – $8.16 / sq ft | $8.64 – $15.35 / sq ft |
| Lifespan | 20 – 30 years | 40 – 70 years |
| Cost per year (midpoint) | about $0.27 / sq ft | about $0.22 / sq ft |
| Roof slope | Low-slope / flat | Sloped; some profiles work on low slopes |
| Energy | White, reflective | Reflective with PVDF or cool-roof finishes |
| Maintenance | Seam and flashing checks | Minimal; check fasteners at trim |
| Hail | Resists with thicker membrane and cover board | Resists punctures but can dent |
Commercial Roof Guide, San Antonio (Mar 2026). Cost per year = midpoint cost ÷ midpoint lifespan.
What Each Costs on a 30,000 Sq Ft Warehouse
| TPO | Standing seam metal | |
|---|---|---|
| Installed cost / sq ft (San Antonio) | $5.28 – $8.16 | $8.64 – $15.35 |
| 30,000 sq ft roof | $158,400 – $244,800 | $259,200 – $460,500 |
| Expected life | 20 – 30 years | 40 – 70 years |
Commercial Roof Guide, San Antonio (Mar 2026). Tear-off, insulation and retrofit framing are extra.
Roof Slope and Structure | What Decides It?
- Flat or very low slope (under about 1/4″ per foot): TPO or another membrane is the practical choice.
- Low slope metal building with screw-down panels: both work. You can replace with standing seam, retrofit, or install TPO over the metal.
- Steeper slope: metal is the natural fit; membranes are rarely used.
- Structure: metal retrofits and SPF add weight, so the purlins and frame must be checked.
Retrofit Options | TPO Over Metal, Coating Over Metal, New Panels
| Option | How it works | Best when |
|---|---|---|
| TPO over metal | Flute filler and rigid insulation fill the panel ribs, then a TPO membrane is installed on top | You want a flat, insulated, reflective roof and the slope is low |
| Coating over metal | Clean, treat rust, replace fasteners, seal laps, coat | Panels are sound and you want the lowest cost |
| Metal-over-metal retrofit | New sub-framing over old panels, new panels and insulation on top (adds about 1.7 – 2.5 lb/sq ft) | Long hold; building must stay dry and in use |
| Tear-off and new panels | Remove old roof, repair purlins, install new metal | Panels are rusted through or structure needs work |
See metal roof repair and restoration and metal building (PEMB) roofing.
How a TPO-over-metal retrofit is built
- Loose fasteners are tightened or replaced and rust is treated.
- Flute filler insulation fills the low ribs of the panels.
- Insulation boards and a cover board create a flat, insulated base.
- The TPO membrane is fastened through the layers into the purlins, then edges and penetrations are flashed.
It works best on low-slope metal roofs where water drains slowly. On steeper metal roofs, a new metal roof or a coating is usually the better fit.
FAQs | Metal vs TPO
Can you install TPO over a metal roof?
Yes. The ribs are filled with flute filler and rigid insulation to create a flat surface, then TPO is installed over it. It works best on low-slope metal roofs and adds insulation in the same step.
Which lasts longer on a warehouse?
Standing seam metal, at 40 to 70 years versus 20 to 30 for TPO. Over a long hold, metal often costs less per year even though it costs more up front.
Is a metal roof cooler than TPO?
Both can be reflective. White TPO is very reflective; metal with a light PVDF or cool-roof finish is too. Insulation underneath matters more for comfort and cooling costs than the surface alone.
Is metal or TPO quieter in rain and hail?
TPO over insulation is quieter. Metal can be noisy in heavy rain or hail unless there’s insulation underneath, which a retrofit typically adds.
Which is better for a warehouse I plan to sell in five years?
Usually TPO or a coating restoration, because the lower first cost matters more than lifespan you won’t use. Metal pays off best for owners holding the building long term.
What are the disadvantages of TPO on a warehouse?
It’s more vulnerable to punctures from foot traffic and dropped tools, seams need periodic checks, and quality varies by product. Walk pads at HVAC units and twice-yearly inspections handle most of this.
Get a Retrofit Assessment
We’ll check your panels, purlins and slope, then price TPO, coating, retrofit and replacement side by side for your warehouse.
- Free roof assessment for warehouses across San Antonio and the I-35 corridor, including warehouse roofing in Schertz, Selma and Live Oak
Book your free roof inspection in San Antonio or see warehouse & distribution center roofing.
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Questions get answered by the roofers who wrote the article, not a chatbot.