How to Estimate a Tenant Improvement Buildout

Typical Office TI Cost Per Square Foot (2026)

These ranges are pre-soft-cost. Add 8–15% for design fees and another 1–3% for permits depending on jurisdiction. Use the building permit cost calculator to sanity-check the permit line for your jurisdiction.

The CSI Division Structure for a TI Estimate

Senior commercial estimators bid TI by walking division by division — Division 02, 03, 04, 05 and so on. The discipline isn't optional. The reason it works isn't because CSI is magic; it's because walking divisions in order forces you to confront every trade scope, even the ones the architect underdrew. Skip the structure and you skip the line items.

Drywall + finishes (Div 09) and MEP (Div 21–23 + Div 26) together carry roughly half the project. Most TI bids that come in wrong are wrong inside those two buckets, usually because demo scope or MEP rework was underestimated.

The Five Most Expensive Misses on a TI Bid

1. Demolition that goes deeper than expected

The architect drew "demolish existing partition" but the partition is hiding two abandoned MEP runs and a structural sleeve. Selective demolition runs $3–$8 per square foot of affected area when scope is clean and $12–$20 per square foot when you discover existing conditions. Walk the space before bidding. If you can't walk it, carry the higher number.

2. MEP rework the architect didn't show

HVAC zoning that worked for the prior tenant rarely works for the new one. Adding 4 zones to a 20,000 sf office is $30K–$60K of equipment plus controls, and another $20K–$40K of duct rework. Same for sprinkler heads — re-stacking partitions almost always means moving heads, and 100 heads on a re-stack is $15K–$25K of labor most bids miss.

3. Firestopping and code upgrade triggers

Any change to a rated wall triggers firestop verification at every penetration. New walls in a rated corridor trigger fire damper review. A change-of-use trigger (going from B-occupancy to A-occupancy) can drag in seismic, egress width, and accessibility upgrades that double the permit cost. Read the building department's TI checklist for the jurisdiction before pricing.

4. After-hours work for an occupied building

If the floor below or above is occupied, expect 30–50% of your demo and concrete work to require after-hours scheduling. Premium time on demo + concrete on a 20,000 sf TI is $25K–$60K of additional labor cost. Verify the building rules and occupancy schedule with the property manager before bidding, not after winning.

5. Low-voltage and AV scope creep

The tenant says "standard data drops" and means 80 cables, two TVs, four conference rooms with full AV, a digital signage package, and a security card reader system. Get the IT/AV scope in writing before bidding. Carry $4–$10 per square foot for low-voltage on a standard office TI; $10–$20 per square foot for a high-end spec.

How to Build the Bid in Two Days Instead of Two Weeks

The standard TI bid timeline is 10 working days from RFP to submission. Half of that is wasted re-pricing line items you already priced on the last three TI bids you sent. The work that actually requires fresh pricing — current MEP sub quotes, current finish material costs, permit-fee verification — is maybe 20% of the estimate. The other 80% is your historical cost library applied to the new scope.

The firms that bid TI work fastest do three things differently. They maintain a TI-specific cost library separate from ground-up. They track actual costs per division on every closed job so the next bid starts from real data, not RS Means averages. And they push live-quote refreshes only on the volatile lines (currently glass, steel, electrical gear) instead of re-pricing everything every time.

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FAQs

What is the typical cost per square foot for office tenant improvement in 2026?

Office TI typically runs $50–$125 per square foot for standard scope, with light refreshes at $25–$45 and high-end custom at $125–$200. Specialty TI (lab, healthcare, broadcast) runs $200 per square foot and up. These are direct construction cost; add 8–15% for design fees and 1–3% for permits.

What's the most underestimated line item on a TI bid?

Selective demolition. Architects routinely show "demo existing partition" without verifying what is inside the wall. Demo costs run $3–$8 per square foot when scope is clean and $12–$20 per square foot when you discover MEP, structure, or hazardous materials. The variance is the largest single source of TI bid losses.

How long does a typical TI estimate take to produce?

Two weeks is industry standard from RFP to bid submission for a 20,000–50,000 sf TI. About 20% of that time is genuinely re-pricing volatile lines (current MEP, glass, steel, finishes). The other 80% is rebuilding line items already priced on prior TI bids. Firms with a structured historical cost library cut total bid time to 2–3 days.

Should TI be priced lump-sum or cost-plus?

Depends on scope clarity. Clean-scope TIs with detailed drawings price well as lump sum and typically carry 5–8% GC fee. Demo-heavy or unknown-existing-conditions TIs price safer as cost-plus with a not-to-exceed cap so the GC is not absorbing the risk of conditions the architect didn't see. Mixed contracts (lump sum for new construction + T&M for selective demo) are common on re-stack jobs.