Sunrooms & Balcony Glazing on Mercer Island, WA
Built and installed by Star Construction WA — Washington State Licensed Contractor #STARCCW791L5, bonded and insured. Authorized Lumon dealer serving Mercer Island and the East Side.
Custom Sunrooms and Lumon Balcony Glazing for Mercer Island Homes
Residential and commercial installations across Seattle, Bellevue, Mercer Island, Everett, Renton and surrounding King County.
Mercer Island sits in the middle of Lake Washington with about 39 inches of rain a year and not much snow — almost the exact climate Lumon’s frameless retractable glass was built for. We install Lumon sunrooms and balcony enclosures for homeowners, waterfront properties, and condo buildings across the island, from First Hill down to the south end and the Mercerwood area.
The system is the same one Lumon has been refining in Finland since the late 1970s, with over a million installations worldwide. Glass slides fully open in summer so a covered deck still feels like an outdoor deck. In fall and spring it closes against the wind off the lake without trapping moisture — the panels have small ventilation gaps built into the edges by design.
For Mercer Island homes specifically, that usually means one of three things: a lake-view deck the owner wants to keep using when the weather turns; a covered patio off the back of the house that’s been sitting half-empty from October to May; or a condo balcony in one of the buildings along 76th or Island Crest Way where the owner wants the view but not the wind. We do free in-home consultations across the 98040 zip code and most projects are quoted within five business days.
OUR PARTNER
Brighten Up Your Home with a Custom Sunroom
A sunroom isn’t a sealed addition. It’s an outdoor space you’ve stopped fighting the weather to use. On Mercer Island, where summer evenings on the water are the whole point of the house, that’s the difference between a deck you enjoy for three months and one you enjoy for nine.
Three-Season Lumon Sunrooms
Lumon’s retractable panels are single-pane tempered safety glass. Each panel slides on its own track. You can open them fully, push them all to one side, leave one or two closed, or seal the whole run flat against weather. There’s a deliberate 2 to 3 mm gap between panels so condensation can’t pool. Most other enclosure systems skip this detail, and that’s why they fail in wet climates.
Lumon manufactures the glass in Finland and the system has been tested in Scandinavian winters that are a lot harder than anything Mercer Island will throw at it.
REQUEST A FREE QUOTEUsing Your Room in Winter
These are three-season rooms, not sealed additions, but Mercer Island winters are mild — daily lows around 37°F and very little snow — so most of our customers are out there in December with a sweater on. A patio heater or a small electric fireplace handles the cold weeks. Lumon themselves suggest an infrared heater or a thermal rug if you want to extend it further.
Don’t expect 70°F in January without a heat source. Do expect to use the room five or six months longer than a screened porch would let you.
REQUEST A FREE QUOTEResidential Sunrooms and Balcony Enclosures on Mercer Island
Most of the residential work we do on the island fits one of three patterns.
The first is a lake-view deck. The homeowner doesn’t want to lose the view, but the deck is unusable in November. A Lumon enclosure closes it in without putting a frame across the sight line — the panels are frameless on three sides, so you read it as glass, not as a window wall.
The second is a back-of-house covered patio, often on the larger lots up near Island Crest Park or off East Mercer Way. These get built as full three-season sunrooms with Lumon panels on two or three sides.
The third is a condo balcony. There are a few HOAs on the island we’ve worked with before and they generally allow Lumon glazing because it doesn’t change the railing or the building envelope — the panels install from inside the existing rail. We’ll check your specific HOA rules before quoting.
The build itself is straightforward. The design decisions aren’t, and that’s where we spend most of the first consultation. A south-facing waterfront lot on West Mercer Way needs different glazing than a north-facing slope above the lake. A patio with a hot tub needs different ventilation than one without. We sit down with you, look at how the room actually gets used, and pick the panel layout from there.
What we install on Mercer Island:
- Glass deck enclosures and glass deck panels for existing decks
- Patio glazing and patio enclosures for covered and uncovered patios
- Porch enclosures and porch glass enclosures
- Custom three-season sunroom additions using Lumon glass
- Lumon balcony glazing for single-family homes and condo units
- Outdoor glass enclosures around hot tubs and pool decks
- Glass walls and glass railings, including frameless glass railing
Commercial Glass Enclosures for Mercer Island Properties
The commercial work on the island is smaller than what we see in downtown Seattle, but it’s there — restaurants on the north end with outdoor seating, condo buildings retrofitting balcony stacks, and a few office and clinical buildings that want to convert a terrace into year-round space. The Lumon system makes sense for all of these because it installs from inside the rail, which means a phased multi-unit install can happen without scaffolding every floor.
We handle the City of Mercer Island permitting, the L&I paperwork, and we coordinate with property managers and general contractors directly. Most commercial installs we’ve done have been phased — a few units at a time, on a schedule that doesn’t disrupt tenants or operations.
Commercial work we take on:
- Restaurant and café patio enclosures, including heated and ventilated configurations
- Hotel and short-term-rental balcony glazing for guest comfort and noise reduction
- Multi-family residential retrofits — phased installations across whole buildings
- Office and co-working terraces converted to year-round meeting space
- Retail and entrance vestibules with retractable glass walls
- Senior living and healthcare facilities — accessible, low-maintenance outdoor space
Why We Install Lumon Glass Systems
Lumon is a Finnish company that’s been making retractable balcony glass since 1978. They have more than a million installations worldwide, and a strong footprint in Canada and Northern Europe — climates wetter than ours.
That matters on Mercer Island for one reason. Pacific Northwest moisture is what kills cheaper enclosure systems. Trapped condensation rots out the framing inside a decade, and then you’re tearing out the whole thing. The Lumon panels are frameless on three sides and slide open in seconds, so the space ventilates the way a screened porch does, but with full weather protection when closed. The glass and aluminum are fully recyclable. The factory warranty is 5 years on materials, with guaranteed spare parts available for 10 years and functional components for 20.
We chose Lumon as a partner because of that long track record. We don’t install anything else.
What to Expect From Quote to Finished Install
Free consultation. We come to your home or building on Mercer Island. Usually 45 minutes. We measure the opening, talk through how you actually plan to use the space, and look at anything unusual with the structure, the view corridor, or the HOA rules.
Written quote within five business days. Itemized — panels, framing, labor, permits, electrical if needed. No “starting at” pricing that creeps up later.
Permits and HOA approval if needed. We handle the City of Mercer Island submissions. For condos, we put together the board package.
Manufacturing. Lumon panels are made to the exact measurements of your opening, so production is typically 4 to 6 weeks.
Install. Most residential balconies are one day. Sunrooms run 3 to 5 days. Commercial phased installs are scheduled around your operating hours.
Walkthrough and warranty. You get the Lumon factory warranty plus our workmanship warranty. Both are registered at the end of the job and the paperwork is yours.
Areas We Cover
RENTON
ISSAQUAH
SAMMAMISH
NORTH CREEK
REDMOND
KIRKLAND
WOODINVILLE
MILL CREEK
Surrounding Area
What Star Construction Customers Say
Recent Residential Projects
Recent Commercial Projects
Frequently Asked Questions About Sunrooms and Balcony Glazing on Mercer Island
How much does a Lumon balcony enclosure cost on Mercer Island?
Most residential balcony jobs on the island come in between $12,000 and $28,000. The variables are linear footage of glass, how the corners are detailed, and whether we’re touching the existing railing. Full sunroom additions are a different scope and usually start around $45,000. You’ll get an itemized written quote — no “starting at” pricing.
Do I need a permit to enclose a balcony or build a sunroom on Mercer Island?
Sunroom additions need a permit from the City of Mercer Island. Most balcony enclosures on existing decks don’t, because we’re not changing the structure, but we always confirm with the city before quoting. Condos need HOA approval first, and we help put together the submission package.
Will a Lumon enclosure add value to my Mercer Island home?
Usually, yes — but how it shows up on an appraisal depends on whether the space counts as conditioned square footage. A Lumon enclosure typically adds value as a usable amenity rather than appraisable living space, because the panels are single-pane and the system is intentionally ventilated. If you specifically need appraisable square footage, that’s a different build and we’ll walk you through the options at the consultation.
How does Lumon glass hold up in Mercer Island’s rain?
The system was engineered for wet climates — Finland, Norway, coastal Canada. Mercer Island gets about 39 inches of rain a year, which is well within what Lumon is designed for. Water drains out through gaps at the bottom of each panel, condensation ventilates naturally, and the glass itself is tempered safety glass. We’ve had installs out for years across King County with no moisture issues.
Can you work with the view corridor and shoreline rules on the island?
Yes. Lumon’s frameless panels are one of the reasons we recommend the system for waterfront lots — there’s no visible frame on three sides of each panel, so it doesn’t break the sight line to the water. For shoreline-zoned properties we’ll confirm setback and view requirements with the city before quoting.
How long does installation take?
A single residential balcony is usually one day on-site once the panels are made. A sunroom runs 3 to 5 working days. Commercial phased installs are scheduled around your operating hours.
What’s the warranty?
Lumon’s factory warranty covers materials for 5 years. Spare parts are guaranteed available for 10 years, and functional and safety components for 20. Our workmanship warranty covers installation labor for 2 years. Both warranties are registered at the end of the install and the paperwork is yours.
Do you serve nearby areas too?
Our regular service area is King and Snohomish counties — Mercer Island, Bellevue, Seattle, Renton, Kirkland, Redmond, Bothell, Lynnwood, Everett, Mill Creek and the surrounding cities.