Owners weighing a renovation against ground-up new construction often go looking for one number: how much higher is the average change order percentage on renovation work? The honest answer is that a clean, sourced side-by-side percentage doesn't exist in the peer-reviewed literature — what does exist is a well-documented renovation-specific study on why existing conditions drive change orders, plus the same industry-wide baseline that applies to both project types. Here's what's actually confirmed, and what predicts a renovation's change order exposure better than a single average would.
What circulates online, and why it doesn't hold up
Search for "renovation vs. new construction change order percentage" and a specific-sounding claim shows up repeatedly across contractor and marketing blogs: renovation change order rates running 40% to 60% higher than new construction, with cost overruns of 15% to 25% versus 5% to 10% for new builds. That figure appears on enough pages, worded almost identically, to look authoritative — but none of the pages that repeat it cite a study, a sample size, or a data source behind it. That's the same pattern flagged in average change order percentage by project type: what the data actually shows: a number that reads as precise but traces back to no verifiable original source isn't something worth building a decision on, so it's left out here rather than repeated.
A statistic that appears on many sites in nearly identical wording, with no study or sample size attached to any of them, is more likely a single unsourced claim being copied forward than an independently confirmed industry figure.
The one renovation-specific study that does hold up
There is a real, peer-reviewed data point on this exact question, and it's narrower than a single headline percentage but more trustworthy for it. A study published in the Journal of Construction Engineering and Management (Vol. 146, No. 8, June 2020) analyzed 517 change orders drawn from 27 building renovation projects, testing whether change orders caused specifically by unforeseen existing conditions carry a different cost impact than change orders from every other cause combined.
The results: change orders tied to unforeseen existing conditions showed a statistically significant, higher mean cost than change orders from other causes on the same renovation projects. The concrete trade generated the highest number of these change orders, while HVAC carried the largest cost impact per change order. That's a real, sourced finding about what happens inside a renovation project's change order profile — not a percentage comparing renovation to new construction, but a documented answer to why renovation change orders behave differently once they happen.
The industry-wide baseline that applies to both
Separate from the renovation-specific study, the general, project-type-agnostic figures still apply as a starting point: change orders industry-wide typically run 8% to 14% of contract value across construction broadly, with a records-based statistical model published through the American Society for Engineering Education independently landing at 5% to 10%. Neither of those figures is broken out by renovation versus new construction — they're aggregated across all project types, the same gap covered in more detail in the sibling piece on change order percentage by project type. What the renovation study adds isn't a new industry-wide average; it's a documented mechanism specific to renovation work that the aggregated figures don't capture.
Why existing conditions are a different kind of risk than new-construction coordination risk
New-construction change order exposure, as covered in where coordination-error costs actually come from, concentrates at the interface points where multiple disciplines' drawings have to agree with each other on a set that's being designed from a clean sheet. A renovation carries that same coordination risk, plus a second, structurally different category: what's actually behind the wall, above the ceiling, or under the slab, which the existing drawings may not accurately represent regardless of how well the new design is coordinated on paper.
That second category is why the concrete and HVAC findings from the JCEM study make sense mechanically. Concrete work in a renovation frequently runs into existing conditions — slab thickness, embedded conduit, structural elements — that don't match record drawings until they're physically exposed. HVAC systems in an occupied or partially occupied renovation have to route around existing structure and existing systems that a new-construction HVAC design never has to negotiate. Both are risks that a document review can reduce by flagging where the new design's assumptions about existing conditions are unverified or inconsistent across drawings, but neither can be fully eliminated on paper the way a coordination conflict between two new-design disciplines can — as also covered in MEP/structural coordination conflicts on renovation and adaptive reuse projects.
What this means for a document review checklist on renovation work
Because renovation carries this additional, existing-conditions category of risk on top of standard cross-discipline coordination risk, a document review checklist built for renovation and adaptive reuse work has to check for something a new-construction checklist doesn't: whether the drawings' assumptions about existing conditions are documented, verified, and consistent across disciplines, not just whether the new-design disciplines agree with each other. That's covered in detail in a document review checklist for renovation and adaptive reuse projects — the short version is that an owner reviewing a renovation set should expect a review to flag unverified existing-conditions assumptions as their own category of finding, priced and sheet-located the same way a cross-discipline conflict would be.
What actually predicts a renovation's change order exposure
Building age, extent of demolition and existing-conditions verification, and how much of the existing structure gets opened up before pricing predict a renovation's change order risk more reliably than a category-wide average — renovation or otherwise — ever could. A light interior fit-out with minimal existing-structure disturbance behaves differently than a gut renovation of a decades-old building with undocumented mechanical systems, even though both are labeled "renovation." The JCEM study's core finding — that unforeseen-condition change orders cost more than other-cause change orders — is exactly why that distinction matters: the risk scales with how much of the project depends on existing conditions the drawings can't fully verify in advance.
Key takeaways
- The widely repeated claim that renovation change order rates run 40–60% higher than new construction isn't traceable to a cited study or sample size — it's left out here rather than reused.
- A real, peer-reviewed study (JCEM, Vol. 146 No. 8, 2020; 517 change orders across 27 renovation projects) found that change orders from unforeseen existing conditions cost significantly more than change orders from other causes on renovation work.
- Concrete was the trade most frequently affected by existing-conditions change orders; HVAC carried the highest cost impact per change order.
- The same 8–14% industry-wide range (and the 5–10% records-based figure) applies as a baseline across project types — renovation's added risk comes from existing conditions, not a separate confirmed percentage.
- Building age, extent of demolition, and how much existing-conditions verification happens before pricing predict a renovation's exposure better than the "renovation" label alone.
An owner comparing a renovation to new construction isn't missing a single percentage to plug into a spreadsheet — that number doesn't exist in a form worth citing. What does exist is a documented reason renovation risk behaves differently, and a specific, priced review of the set in front of you that checks both categories of risk a renovation actually carries: cross-discipline coordination and unverified existing conditions.
Frequently Asked Questions
Is it true that renovation projects have 40–60% higher change order rates than new construction?
That figure circulates widely across contractor and marketing blogs, worded almost identically on many of them, but none trace it back to a cited study, sample size, or original data source. It's treated here as unconfirmed rather than repeated as fact.
What does the peer-reviewed research actually say about renovation change orders?
A study published in the Journal of Construction Engineering and Management (Vol. 146, No. 8, June 2020) analyzed 517 change orders across 27 building renovation projects and found that change orders caused by unforeseen existing conditions had a significantly higher mean cost than change orders from all other causes combined.
Which trades are most affected by existing-conditions change orders in renovation work?
Per that same study, concrete was the trade most frequently affected by change orders tied to unforeseen existing conditions, while HVAC carried the highest cost impact per change order.
Does the general 8–14% industry-wide change order range apply to renovation projects too?
Yes — that range (and a separate, records-based statistical model landing at 5–10%) is aggregated across construction project types generally, including renovation. It's a reasonable starting baseline, but it doesn't capture the additional existing-conditions risk that renovation-specific research has documented separately.
What predicts a renovation project's change order risk better than a category average?
Building age, how much of the existing structure gets opened up before pricing, and how well the existing-conditions assumptions in the drawings are verified across disciplines. A light fit-out and a gut renovation of an older building carry very different risk profiles despite sharing the same "renovation" label.