Seattle Office Tenant Improvement Cost (2026): $50–$150/sq ft, by Scope

Seattle Office Tenant Improvement Cost (2026)

Updated: August 2026 · Puget Sound region · Planning figures, not quotes

Most office tenant improvements in Seattle land in a typical 2026 planning range of $50 – $150 per square foot. Light cosmetic refreshes — paint, carpet, lighting — come in below that. Full-gut renovations and high-spec buildouts commonly run $150 – $250+ per square foot. Shell condition, mechanical and electrical scope, and finish level drive most of the variance.

Those are planning figures for budgeting, not quotes. A walkthrough is what turns a range into a scoped number.

Cost by scope

The same 3,000 sq ft suite prices very differently depending on what is above the ceiling and behind the walls. Second-generation space with usable HVAC, restrooms, and a ceiling grid already in place starts far cheaper than a cold shell.

What moves the number

Shell condition. This is the single biggest swing. Reusing existing HVAC distribution, restrooms, and ceiling grid can keep a project at the low end of the range. A cold dark shell — no ceilings, minimal utilities — pushes toward the high end before a single finish is chosen.

Mechanical and electrical scope. Moving walls is cheap relative to moving the systems that serve them. A layout change that forces new HVAC distribution, added circuits, or a panel upgrade moves the per-square-foot number more than the finish schedule usually does.

Finish level. Mid-grade commercial finishes sit inside the standard range. Stone, architectural millwork, specialty glazing, and high-end AV are what carry a project past $150 per square foot.

Change of use. If the project changes how the space is used, expect a change-of-use review and possibly upgrades to exiting, accessibility, or fire systems tied to the new occupancy. This is the most common source of budget surprise, because the trigger is regulatory rather than architectural — the tenant did not ask for it and it is not optional.

Schedule

A straightforward office or retail tenant improvement typically runs 6 – 12 weeks of construction once permits are issued.

Review timelines are the part owners underestimate. A simple TI with no change of use can clear plan review in a few weeks. Change-of-use, structural, or food-service projects routinely take two to four months in Seattle. Projects involving structural work or change of use commonly run 3 – 6 months end to end including permitting.

The practical consequence: permitting should start when the proposal is signed, so plan review runs in parallel with procurement instead of blocking the schedule.

The permit path

Most commercial tenant improvements follow a predictable sequence:

1. A building permit, with plan review for anything beyond cosmetic work.
2. Separate trade permits for electrical, plumbing, and mechanical.
3. Change-of-use review, where the use is changing.
4. Health department plan review with Public Health – Seattle & King County, for food service.

Requirements, fees, and review timelines differ by city. Trade permit detail by jurisdiction:

• Seattle electrical permits · Seattle plumbing permits
• Bellevue permit requirements
• Kirkland electrical permits
• Renton HVAC permits
• Overview: permit guides by city

How to budget before you have a scope

Multiply your usable square footage by the range that matches your shell condition, then carry the change-of-use question separately — it is the item most likely to move the number after the fact.

For a first-pass figure, the project cost calculator will get you a bracket. For a real one, a scoped walkthrough is the only thing that produces a number worth committing to a lease negotiation.

Kolmo Construction is a Washington general contractor working in Seattle, Bellevue, Kirkland, Redmond, Renton, Tacoma, and Everett, across King, Pierce, and Snohomish counties. Credentials are verifiable at kolmo.io/verify.