Two-Story Great-Room Expansion in Mercer Island, WA

Two-Story Great-Room Expansion in Mercer Island, WA

Xion Build provides expert two-story great-room expansion in Mercer Island. As a trusted Mercer Island home additions contractor, we manage design, materials, permits, and every trade in-house so your project stays on schedule and on budget. Vaulted, two-story living additions with structural steel where needed.

Mercer Island projects often involve sloped lots, shoreline rules, and mid-century homes that benefit from thoughtful structural and design planning.

From room additions and bump-outs to second stories and full primary suites, we handle structural engineering and permits up front so there are no surprises.

What's included in your two-story great-room expansion

A typical two-story great-room expansion in Mercer Island can involve roofline tie-in, finishes, windows, insulation — and we put the full scope in writing so you know exactly what's covered before work starts.

A home addition lives or dies on the connection to the existing house — foundation, framing, and rooflines have to marry seamlessly so the new space feels original.

How much does a two-story great-room expansion cost in Mercer Island?

Most two-story great-room expansion projects in Mercer Island fall between $160,500 – $468,500, depending on the size of the space, the finishes you choose, and the condition of what's already there.

Because every home is different, we don't quote final numbers sight unseen. After a free in-home consultation you get a detailed, itemized estimate tied to your actual home additions project — so there are no surprises later.

Why Mercer Island homeowners choose Xion Build

Licensed, bonded, and insured in Washington — every project is built to meet or exceed code and backed by a written warranty.

Honest guidance on where to invest and where to save, so your budget goes toward what adds real, lasting value.

One dedicated point of contact coordinates the entire job, so you're never chasing subcontractors or wondering who's responsible.

Our Mercer Island home additions process

Each phase is inspected and documented, and we keep you updated so you always know what's happening and what's next.

Handoff includes a detailed walkthrough and a written warranty — not a crew that vanishes the moment the dust settles.

It starts with a free, no-obligation consultation: what you want, the constraints, and a realistic budget range before you commit to anything.

Frequently asked questions

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