South Lake Union trophy buildings deliver a high-end Cat-A baseline; tenant fit-out typically lands in the High-end or Trophy bands.

• Typical spec: 15–40,000 sqft floor plates available across newer Class A stock; 9'+ slab-to-slab and modern MEP common.
• Seattle fit-out range — Basic $85–120/sqft, Trophy $270–410/sqft.
• Submarket tier: trophy.

TL;DR

• Typical spec: 15–40,000 sqft floor plates available across newer Class A stock; 9'+ slab-to-slab and modern MEP common.
• Seattle fit-out range — Basic $85–120/sqft, Trophy $270–410/sqft.
• Submarket tier: trophy.

Spec baseline

15–40,000 sqft floor plates available across newer Class A stock; 9'+ slab-to-slab and modern MEP common.

Cost bands

City-wide Seattle fit-out bands: Basic $85–120/sqft, Mid $125–180/sqft, High-end $185–270/sqft, Trophy $270–410/sqft.

Key facts

Frequently asked questions

What spec level is normal in South Lake Union?

15–40,000 sqft floor plates available across newer Class A stock; 9'+ slab-to-slab and modern MEP common.

Related

• South Lake Union — submarket overview
• Seattle — full city profile
• Seattle submarkets — all
• South Lake Union — Rents
• South Lake Union — Tenants
• South Lake Union — Transit
• South Lake Union — Amenity

Editorial provenance

Reviewed by Miriam Hollander — Lead market analyst. Last updated 2026-04-15. See our methodology and editorial standards.

Primary sources for this page

• CBRE Marketview reports — CBRE
• JLL Office Insight — JLL
• Cushman & Wakefield Marketbeat — Cushman & Wakefield
• Savills World Research — Savills
• Colliers Global Office Outlook — Colliers

Full sources index · Submit a correction

Related topics

• Class A Lease Negotiation — How to negotiate a Class A office lease — the playbook from LOI to signed deal.
• Hybrid Workplace Strategy — How to size, structure, and lease a Class A office for a hybrid workforce.
• ESG / LEED for Tenants — How tenants evaluate, negotiate, and report on ESG performance in a Class A office lease.
• Cross-border Expansion — How to run a coordinated Class A office search across multiple geographies.
• Fit-out Capex — How to budget, sequence, and govern Class A office fit-out capex.
• Lease vs Flex — When premium flex (coworking, managed office) beats a conventional Class A lease — and vice versa.