Home additions · Mercer Island, WA
Room Addition in Mercer Island, WA
Add a bedroom, office, or living space tied seamlessly into the home.
Room Addition in Mercer Island, WA
Xion Build provides expert room addition 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. Add a bedroom, office, or living space tied seamlessly into the home.
Mercer Island projects often involve sloped lots, shoreline rules, and mid-century homes that benefit from thoughtful structural and design planning.
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.
What's included in your room addition
A typical room addition in Mercer Island can involve windows, roofline tie-in, finishes, insulation — and we put the full scope in writing so you know exactly what's covered before work starts.
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.
How much does a room addition cost in Mercer Island?
Most room addition projects in Mercer Island fall between $78,000 – $260,000, 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
Local crews who know Eastside permitting, inspections, and the way Pacific Northwest weather tests a home.
Transparent, written estimates with no hidden fees — you know what you're paying for before work begins.
Honest guidance on where to invest and where to save, so your budget goes toward what adds real, lasting value.
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.
We pull the permits, schedule every trade in the right order, and protect your home, landscaping, and daily routine throughout the build.
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
How much does a room addition cost in Mercer Island?
Most room addition projects in Mercer Island run $78,000 – $260,000, depending on scope, finishes, and existing conditions. After a free in-home consultation we provide a detailed written estimate so your Mercer Island price reflects the actual project — not a guess.
Do you offer free estimates for room addition near Mercer Island?
Absolutely. We provide free, no-obligation in-home estimates throughout Mercer Island and the greater Eastside, with transparent, itemized pricing.
Do you offer a room addition in Mercer Island, WA?
Yes. Add a bedroom, office, or living space tied seamlessly into the home. Xion Build is a licensed, bonded, and insured home additions contractor serving Mercer Island and the surrounding WA communities.
How long does a room addition take?
Timelines depend on scope and permitting. Once the plan is confirmed we give you a realistic schedule and keep you updated as the home additions work progresses.
Are you a licensed home additions contractor?
Yes — Xion Build is licensed, bonded, and insured in WA. Every project is built to meet or exceed code and is backed by a written warranty.
Related services in Mercer Island
Mudroom & entry addition
Drop-zone mudrooms with lockers, benches, and storage.
View detailsBump-out addition
Small cantilevered bump-outs to expand kitchens, baths, or dining.
View detailsHome office addition
A quiet, code-built dedicated workspace with proper electrical.
View detailsGarage addition
Attached or detached garages framed, wired, and finished.
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