Renovation and tenant improvement (TI) projects may appear straightforward on paper, but for estimators, they’re a different kind of beast entirely. Unlike new construction—where you’re pricing from a clean slate—these projects come with a hidden history. What lies behind the walls, above the ceiling grid, or beneath the floor slab is often unknown until the demolition crews start swinging hammers.
That uncertainty creates a fundamental challenge: how do you produce a responsible, realistic estimate for a project where part of the scope hasn’t revealed itself yet?
The Illusion of Simplicity
From the client’s perspective, renovation and tenant buildouts can feel “easier” than new builds. No major sitework, no new structure, and often no permits beyond interior renovations. But that perception is misleading.
In reality, estimating for renovations often requires more experience, more risk management, and more creative thinking than greenfield work. An estimator must assess not just what’s on the plans, but what’s not there—and account for the inevitable unknowns that come with aging infrastructure, incomplete as-builts, and unforeseen conditions.
Risk Hiding in Plain Sight
The biggest enemy of any renovation estimate? Unknown conditions.
These can include:
- Hidden mechanical, electrical, and plumbing (MEP) systems that don’t match record drawings
- Structural modifications made over decades without proper documentation
- Asbestos or other hazardous materials concealed behind finishes
- Inadequate code compliance of existing systems
- Fire-rated assemblies that were never installed—or are now compromised
- Previous workarounds or “creative fixes” that only show up during demo
Unlike new construction, where plans and specifications rule, renovation estimates must contend with what’s actually built, and the only way to know that is through detailed site walks, selective demolition, and investigation.
Contingency ≠ Guesswork
Estimators are often asked, “Why is the contingency so high?”
The answer: because it has to be.
But good estimators don’t just throw in an arbitrary 10% and call it a day. They define contingency based on:
- Historical project data: What types of issues typically arise in similar buildings?
- Building age and system type: Older buildings with multiple renovations often hide more surprises.
- Extent of demolition: Selective demolition increases risk—full gut jobs offer more clarity.
- Scope clarity: The less defined the design, the more contingency is required.
- Access and logistics: Working in occupied spaces or downtown high-rises affects everything from labor productivity to material delivery costs.
Contingency is not padding—it’s responsible risk pricing. But it must be documented clearly in the estimate and, ideally, broken down by risk category. Doing so gives stakeholders a better understanding of where the budget pressure points may emerge.
Allowances Done Right
Another common mistake in TI and renovation estimating is the misuse of allowances. These are tools, not trash bins for uncertainty.
A well-structured allowance should:
- Be tied to a defined scope of work (e.g., light fixture replacement, flooring system upgrades)
- Include clear assumptions on square footage, quality level, and access
- Be based on realistic unit costs, not wishful thinking
- Include escalation if procurement is delayed
When allowances are vague or inflated “just in case,” they create problems downstream. Overly optimistic allowances lead to budget busts during procurement. Overly padded allowances often get value-engineered or criticized as fluff. Either way, trust is lost.
Think of allowances like temporary place-holders in your estimate. They’re only effective if they come with a “handle” – something that tells the owner, designer, and construction team how and when they’ll be replaced with actual scope and costs.
Productivity Hits and Hidden Costs
Estimating the cost of work in an occupied building or tight urban environment isn’t as simple as slapping on a “working in an existing space” factor.
Real productivity hits come from:
- Limited laydown or storage space
- Night or weekend work to avoid disrupting tenants
- Work in phases to keep areas operational
- Coordination with existing systems, often requiring detailed shut-down procedures
- Fire watch or escorts required during intrusive work
Estimators need to understand these project-specific logistics and consult with superintendents or operations teams early. A 10% productivity hit on labor isn’t unusual in these situations—but you have to justify it with reasoning, not just gut feeling.
Demo Is Not Free (and Never Simple)
One of the most underappreciated components in TI and renovation estimates is demolition.
Too often, demolition is priced as a low-dollar-per-square foot activity with little thought. But selective demo is delicate, often hand-performed, and involves:
- Hazardous material abatement
- Salvage or protection of existing finishes
- Temporary power and HVAC rerouting
- Cutting, patching, and firestopping
- Permits and haul-off fees
Don’t forget to account for temporary barricades, floor protection, dust containment, and even working hours limits. This isn’t the wrecking ball—it’s surgery, and your estimate needs to reflect that.
Clear Communication: The Estimator as Educator
More than almost any other type of project, renovations require estimators to educate stakeholders.
The best estimates include a Basis of Estimate (BOE) that outlines:
- What was known and unknown at the time of pricing
- What existing conditions were assumed to remain
- What assumptions were made for systems, finishes, access, and scheduling
- Clarifications on what is included and excluded
- How contingency and allowances were calculated
A well-written BOE turns your estimate from just a number into a decision-making tool. It also protects you as an estimator when surprises inevitably surface.
Lessons Learned from the Trenches
Let me share a quick story from the field. On a recent adaptive reuse project converting an old department store into office space, the drawings showed one floor slab thickness. After demo began, the team found three different slab types—each with different reinforcing, elevations, and patch conditions.
That difference cost over $200,000 in slab infill, cutting, and grouting—none of which was visible at time of estimate. But because the estimator had included contingency for “unknown floor conditions” and documented it in the BOE, the client didn’t panic. The Team pivoted, reallocated funds, and kept the project on track.
That’s the power of estimating done right: not just identifying risk—but preparing for it.
Conclusion: Estimating the Unseen
Renovations, tenant improvements, and adaptive reuse projects may not involve tower cranes or deep foundations, but they test the estimator in other ways—especially in risk identification, logistics planning, and communication.
Good estimating here isn’t about being perfect. It’s about being realistic, transparent, and prepared for surprises hiding behind the walls.
Because in renovation, it’s not a matter of if you’ll find something unexpected. It’s when—and whether your estimate helped the team handle it.
“Knowing is not enough; we must apply. Willing is not enough: we must do.”
– Johann Wolfgang von Goethe
– German writer and philosopher (1749 -1832)
About the Author
Andrew Kleimola is a Certified Estimating Professional with over 35 years of experience in construction and cost consulting. He currently leads estimating efforts as part of the Infrastructure & Capital Projects (IC&P) team at Accenture, where he serves as an Independent Cost Estimator and Owner’s Representative on complex aviation, infrastructure, and public-sector projects. Andrew is an active member of American Society of Professional Estimators (ASPE), ASPE Orlando Chapter 50, and a dedicated advocate for elevating the profession of estimating through mentorship, education, and industry engagement.
