The Bixby Roof Assessment That Cut a
Replacement Scope in Half
A mixed modified bitumen and TPO roof, assessed section by section, with one half recommended for replacement and the other confirmed to be in good shape.
Assessment by Cole Corvin
Decor Roofing & Restoration · Field assessment May 26, 2026
Location
Bixby, OK
Property Type
Retail property
Roof Systems
Modified bitumen and TPO
Area Assessed
About 8,630 sq ft (mod bit)
In May of 2026, our team assessed the mixed roof system on a retail property here in Bixby, Oklahoma. The building carries roughly 8,630 square feet of gravel surfaced modified bitumen alongside a section of TPO membrane, and the two were in very different shape. The modified bitumen had reached the end of its service life and needed replacing, at an estimated $75,000 to $143,000, or about $8.70 to $16.60 per square foot depending on what the decking looks like once we get the old system off. The TPO section, on the other hand, needed no capital work at all. Just a good maintenance plan to keep it performing well for years to come.
Half a replacement instead of a whole one. That is exactly what a section-by-section assessment is for.
Why the Owner Called
A roof that is part gravel surfaced modified bitumen and part TPO does not age as one roof. It ages as two. The owner of this Bixby property was seeing exactly that: visible wear on the older sections, real uncertainty about the rest, and no documented basis for deciding whether to repair, replace, or simply wait a while longer.
It would have been easy enough to write up a full re-roof and be done with it. We would rather walk every section of a roof and let what we actually find determine the scope. That tends to be better for the building, and it is always better for the owner’s budget.
What the Assessment Found
The Modified Bitumen Sections: End of Service Life
During the May 26 walk-through, we documented five distinct deficiency patterns across the gravel surfaced modified bitumen areas:
Documented Deficiencies
Membrane dislodged from the parapet wall, leaving open voids where wind and water can get directly into the system
An open wall joint on the southeast side of the building
Cracks and voids at the inside corner flashing details, which is the geometry where flat roofs tend to fail first
Widespread cracking and bare spots with no UV protection, showing up as dark patches of exposed asphalt across the field where the protective gravel surfacing has displaced
Damaged plank decking beneath the roof system around an out-of-service penetration pipe, which is structural damage rather than simple membrane wear
Taken one at a time, several of these could be patched. Taken together, they describe a system that has moved past the point where repairs make good economic sense. Patching this many failure points would come close to replacement cost, and none of that work would qualify for a manufacturer or contractor warranty. We would much rather see an owner put that money toward warranted work that adds real value to the building.
The TPO Section: In Good Shape, and Best Left Alone
That same walk-through put the TPO section in an entirely different category. The membrane is intact, the seams are performing, and there is no capital work to justify right now.
Our recommendation for this section was a proactive maintenance plan, with scheduled inspections, drainage clearing, and seam checks, rather than any replacement spend at all. On a mixed system roof, that is often the finding that saves an owner the most money. The assessment simply has to be honest enough to say that this part is doing just fine.
The Recommendation and the Numbers
| Roof Section | Finding | Recommended Action | Investment |
|---|---|---|---|
| Modified bitumen (about 8,630 SF) | End of service life, and repairs would not be warrantable | Full replacement of these sections | $75,000 to $143,000 $8.70 to $16.60 per sq ft |
| TPO section | Good condition | Maintenance program enrollment | No capital expenditure |
What This Means If You Own a Commercial Roof in Bixby
Three things we took away from this assessment apply to just about any aging commercial roof around the Tulsa metro:
Mixed system roofs deserve section-by-section verdicts.
If your building has two roof systems and the report comes back with a single overall condition rating, it is fair to ask how closely each section was walked.
The warranty question settles most repair versus replace debates.
If a repair scope cannot qualify for a manufacturer or contractor warranty, that money will usually go further put toward replacement instead.
A well explained range beats a tight number built on guesswork.
Deck conditions are not knowable before tear-off. An estimate that accounts for that openly, and tells you how it will be handled, will serve you better than one that does not.
Carlisle Perfection Award
Top 5% of installers, US and Canada
Documented Condition Reports
Section by section, photo verified
BBB A+ Since 2000
Over 50 million sq ft installed
Headquartered in Bixby
Commercial roofing since 1987
We Would Be Glad to Walk Your Roof
We have been assessing and maintaining commercial roofs across Bixby, Tulsa, Broken Arrow, Jenks, Sand Springs, and Owasso since 1987, from our home office at 3023 E 151st St S right here in Bixby, just a few minutes from the property in this case study. You will get a documented, section-by-section condition report, including the sections that do not need a thing.
Frequently Asked Questions
This Bixby project scoped at $8.70 to $16.60 per square foot for approximately 8,630 square feet, with the range driven by what the deck repairs look like after tear-off. Access, insulation requirements, and code upgrades can move an individual project within that band or beyond it.
Manufacturer and contractor warranties require a substrate that is in warrantable condition to begin with. When a membrane is showing systemic failure, such as displaced surfacing, open flashings, and deck damage underneath, spot repairs are sitting on a failing system, and no manufacturer will stand behind them.
Not necessarily, and this case study is a good example of why. Roof sections installed at different times, or built from different systems, age independently of one another. A section-by-section assessment can isolate the replacement scope to the areas that have actually failed and put the healthy sections on a maintenance plan instead.
Deck damage gets confirmed and priced after tear-off, once it is visible. The process we use is a documented, separate line item submitted for approval before that work moves forward, rather than a guess folded into the original bid.
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This assessment was performed as part of Decor’s commercial roofing services across the Tulsa metro.