Squares and Square Feet
Before the numbers, one thing worth knowing. Roofers measure in squares. A square is 100 square feet of roof surface. A 20,000-square-foot warehouse roof is 200 squares. Residential roofing is usually quoted per square. Commercial flat roofing is usually quoted per square foot, because building owners already think in square feet and it makes buildings of any size easy to compare. Same measurement, different unit. If a bid says $850 a square and another says $8.50 a square foot, they're the same price. We'll quote you whichever way you think, and we'll show both if it helps.
Commercial Roof Cost by Material
Flat and low-slope roofing is priced per square foot installed. These are planning ranges for commercial buildings across Grand Rapids, Holland, Kalamazoo, and the surrounding communities.
TPO (Thermoplastic)
$6 – $10 / sq ft
Typical service life: 20 to 30 years. White, reflective, heat-welded seams. Lowers cooling costs and has been gaining ground fast for twenty years. Typically costs less than EPDM.
EPDM (Rubber)
$6.50 – $11 / sq ft
Typical service life: 20 to 30 years. The most common flat roof in West Michigan for decades. Very long-lived, dark surface helps shed snow, flexes through freeze-thaw, easy to repair as it ages.
Modified Bitumen
$6.25 – $12 / sq ft
Typical service life: 15 to 25 years. Multi-layer membrane, self-adhered or torch-applied. Handles freeze-thaw, forgiving on roofs with a lot of curbs and penetrations, easy to repair down the road. Also our first choice on residential flat roofs.
Roof Coatings and Restoration
Silicone $3.50 – $7 / sq ft. Acrylic $2.50 – $5.50 / sq ft. Full restoration $4 – $8 / sq ft.
Adds 10 to 20 years to a roof with a sound deck. Silicone for flat and ponding roofs, acrylic for metal and anything with slope, a full restoration system with reinforced seams and fabric at every penetration for aging membrane roofs. Adhesion test on every substrate first. Often treated as a maintenance expense rather than a capital replacement, confirm with your accountant. Full detail on our coatings page.
Learn MoreTapered Insulation
$2 – $4 / sq ft added under the membrane
Service life: matches the membrane. Polyiso board milled at an angle to build drainage slope into a roof that doesn't have enough. Not every ponding roof needs it. If the deck already slopes to a drain or scupper, we leave well enough alone. If it doesn't, tapered is what makes the membrane last, and it helps meet Michigan energy code R-values in the same layer. We design and lay out tapered systems in-house.
Standing Seam Metal
Starts around $12 / sq ft, can exceed $25 – $30
Typical service life: 40 to 70 years. For low-slope commercial and agricultural buildings. Highest upfront cost, longest life, and most of the price is in the accessory work at every edge and penetration. See our metal page.
Learn MoreRanges reflect installed cost including standard tear-off or prep, membrane, adhesives, flashing, and cleanup. Every building is different. The only way to get an accurate number is a free on-site inspection and measurement, and on a flat roof that includes a moisture survey.
What Drives Flat Roof Cost Per Square Foot
A basic single-ply recover on a clean, open deck comes in near the bottom of the range. A full tear-off with wet insulation coming out, tapered insulation going in, new drains, and dozens of equipment curbs lands near the top.
Membrane thickness (45-mil, 60-mil, 80-mil), insulation R-value, roof access, and what's hiding under the old system all move the number. We spell every line out in writing so you know exactly what you're paying for, and we spell out the assumptions, so if the deck is worse than expected you already know how that's handled.
What Changes Your Commercial Roof Price
Two buildings the same size can price very differently. These are the things our inspectors evaluate on every commercial roof:
- Total roof square footage and deck layout
- Number of drains, scuppers, curbs, skylights, and HVAC units
- Full tear-off versus recover (reskin) versus restoration coating
- Whether the existing insulation is dry, or coming out wet
- Insulation upgrades and required R-value
- Tapered systems where ponding needs correcting
- Building height, staging, and roof access
- Hidden deck, wood, or steel repairs
Seven Factors, Explained
Roof Size and Layout
Commercial roofing is priced per square foot, so total square footage drives the base number. Larger, simpler decks earn better per-foot pricing. Small roofs cluttered with equipment cost more per foot, because every piece of equipment is a flashing detail.
Rooftop Penetrations
Every drain, curb, skylight, HVAC unit, and pipe needs custom flashing and detailing. On a flat roof, the joints are where it fails, not the field, and every penetration is a joint. A roof packed with units costs more to waterproof than an open field.
Tear-Off, Recover, or Coating
Stripping one or more old layers, disposing of them, and prepping the deck adds labor and dumpster cost. When the deck is sound and there's one layer with no wet insulation, a recover, what most of us in Michigan call a reskin, avoids that expense. When the deck is sound and the membrane is just aging, a restoration coating avoids even more. We scan for moisture first, then tell you which one you're looking at.
Wet Insulation
This is the one that surprises people. If the moisture survey finds saturated insulation under the membrane, it comes out. Coating over it or recovering over it just traps the problem. That's a real cost, and it's a cost we flag before the quote, not after the roof is open.
Insulation and R-Value
Michigan energy code sets minimum roof insulation on a replacement, and your heating bill rewards going past it. Adding or upgrading polyiso, especially tapered, raises material cost but pays back in comfort, efficiency, and a membrane that isn't sitting in a puddle.
Roof Access and Height
A single-story building with easy ground access is far cheaper to stage than a multi-story roof needing cranes, lifts, or after-hours work to avoid disrupting tenants.
Deck Condition
Rotted wood, rusted steel, or delaminated concrete discovered during tear-off has to be fixed before the new system goes on. We flag likely repairs during the inspection and price them as an allowance or get your approval once we can see them, so there are no surprises.
The Real ROI Is Maintenance
The cheapest commercial roof is the one you already own, kept healthy. Flat roofs don't fail in the field. They fail at the seams, drains, flashings, and penetrations, and they fail slowly, which means they're catchable. A twice-a-year maintenance program costs a small fraction of a premature tear-off, extends the life of the membrane by years, and keeps the manufacturer warranty in force, since most require documented periodic inspection. Sealing a lifted seam or clearing a clogged drain today prevents interior damage, inventory loss, and emergency call-outs tomorrow. For property owners, it's one of the highest-return line items on the building.
(616) 840-1927No Guessing. A Written Quote.
Every price on this page is a real-world West Michigan planning range, not a binding quote. Commercial roofs vary too much. Membrane type, layers to remove, whether the insulation is wet, tapered or not, drainage, and deck condition all move the number.
Stellar Roofing Company measures your roof, runs a moisture survey and an adhesion test where a coating is in play, flags hidden repairs, and puts everything in writing so you can budget with confidence. If the roof is a candidate for a coating instead of a replacement, we'll say so. And if you're weighing the capital, we offer commercial financing, which very few roofing companies in West Michigan can say.
- Free on-site measurement and moisture survey
- Written, line-item pricing with the assumptions spelled out
- TPO, EPDM, mod bit, coating, and tapered options
- Commercial financing available
- West Michigan owned, over 1,600 commercial roofs since 2012
Explore related pages: Commercial Roofing, Roof Coatings, Roof Maintenance, Flat Roof Repair, Financing
Commercial Roof Cost Questions
How much does a commercial flat roof cost in West Michigan?
Most commercial flat roof projects land between about $6 and $12 per square foot installed depending on the system. TPO typically runs $6 to $10, EPDM $6.50 to $11, modified bitumen $6.25 to $12. Coatings and restorations run $2.50 to $8 depending on the system, and tapered insulation adds $2 to $4 per square foot where it's needed. A square foot is what it sounds like. A square is 100 of them. Final pricing depends on an on-site inspection and moisture survey.
Is TPO or EPDM better for a Michigan commercial building?
Both perform well here. EPDM has been the most common flat roof in West Michigan for decades and is very long-lived and easy to repair. TPO's white reflective surface reduces summer cooling costs, its heat-welded seams are extremely watertight, and it typically costs less. For a heated, air-conditioned building we often lean TPO. For a large, simple deck where longevity is the priority, EPDM is hard to beat. We recommend a system after we inspect the roof and understand how the building is used, not before.
Can I coat my old flat roof instead of replacing it?
Often, yes. If your deck and insulation are dry and structurally sound, and the coating passes the adhesion test, a silicone or acrylic restoration can add 10 to 20 watertight years for well under half the cost of a full tear-off. Coatings only work over a roof that isn't saturated underneath, so we run a moisture survey first. When the insulation is wet or the deck is failing, replacement is the right call and we'll say so.
Why does my flat roof pond water, and what does fixing it cost?
Ponding means the roof has lost slope: compressed insulation, a settled deck, or clogged drains. NRCA defines ponding as water still on the roof 48 hours after rain, and manufacturer warranties require positive drainage. Sometimes the fix is tapered insulation, roughly $2 to $4 per square foot. Sometimes it's a drain, a scupper, or a cricket. Sometimes the deck already slopes fine and a drain is plugged. We figure out which before we quote it, and we don't sell tapered if the roof doesn't need it.
Does a maintenance program actually save money?
Yes. Two inspections a year plus minor seam, flashing, and drain upkeep costs a small fraction of a premature replacement, extends the membrane's life by years, and keeps the manufacturer warranty valid, since most require documented periodic inspection. Catching a lifted seam or clogged drain early prevents interior damage, inventory loss, and emergency call-outs. For commercial owners it's one of the highest-return line items on the building.
Will you give me a firm price without seeing the roof?
No, and be cautious of any contractor who does. The ranges on this page are real planning numbers, but membrane choice, tear-off layers, wet insulation, deck condition, drainage, and roof access all move the final figure. We provide a written, no-obligation quote after a free on-site inspection, measurement, and moisture survey.