Premium Wood Siding — Lunawood, Accoya & Shou Sugi Ban for Pacific Northwest Homes
Installed by Paul Gubenya — WA General Contractor License #GPGENGC830KD · James Hardie Certified Installer · 5.0★ Google reviews
For custom builds and high-specification remodels where architects specify natural wood that can outlast cedar in PNW rain: we install three premium wood systems — thermally-modified Lunawood, acetylated Accoya, and traditional Japanese Shou Sugi Ban. All three are 50-year-class materials when installed to spec with stainless fasteners and a ventilated rainscreen. Installed by a James Hardie Certified Installer who also knows how these materials move.
GP General Corp installs premium architectural wood siding across Seattle, the Eastside, and Snohomish County — thermally-modified Lunawood, acetylated Accoya, and Japanese Shou Sugi Ban charred cedar, over a ventilated rainscreen. WA license GPGENGC830KD, MBAKS member, rated 5.0 on Google. Real installed rates on our pricing page; free written quote after an on-site assessment.
By Paul Gubenya — Owner, James Hardie Certified Installer · WA License #GPGENGC830KD · MBAKS Member · Rated 5.0 on Google · (425) 344-9635
What Homeowners Say
Real reviews from our Google profile — unedited, from real projects.
“We recently had Paul with GP General repair a damaged corner protector and sidings. His estimate was reasonable, his availability was timely, and his job was excellent. Our home hadn’t been re-painted in a while and the paint had considerably faded, yet he was able to match the color perfectly. Now we know who to turn to when in need of another repair work.”
“GP General replaced LP siding on our garage. Paul was very thorough when he came out to do the estimate; he listened to my concerns and was able to work out solutions on the spot. His crew did a great job and were very courteous. They also were careful about cleaning up (I didn’t find any nails!). Really happy with the job and can recommend GP General.”
“I highly recommend GP General Corp for siding replacement. We recently had our wood siding replaced with James Hardie lap siding, and Paul and his team did an excellent job.”
Why Premium Wood in the Pacific Northwest
Standard western red cedar is still a beautiful siding material — but in the Puget Sound climate, untreated cedar averages 20-30 years before major maintenance, and its dimensional movement with seasonal humidity makes tight-detail architectural jobs difficult. For custom homes on Mercer Island, Medina waterfronts, and Bellevue hillside lots where the architect wants natural wood with 50-year performance, we install three premium alternatives. Each one solves a different problem: Lunawood for warm Scandinavian aesthetic with low chemical input, Accoya for the highest durability warranty in the industry, and Shou Sugi Ban for projects where the design language calls for deep-black textured wood that’s been doing the job in Japan for 700 years.
Recent project: Mercer Island Hardie reside with Shou Sugi Ban charred fir shiplap accent →
All three materials are more expensive than cedar up front — $22 to $60 per square foot installed versus $16 to $28 for cedar. The premium buys you material-level durability (not finish-coating durability), meaning the replacement cycle is measured in generations rather than decades. For high-value homes where scaffolding, permit filings, and design approval cycles make re-siding a five-figure event, the math usually favors premium wood even before finish savings.
Lunawood — Thermally Modified Scandinavian Pine
$22–$32/sqft installedWhat it is: Northern pine or spruce from Finland heat-treated at 212°C in a low-oxygen kiln. The thermal modification breaks down the sugars and resins that feed fungal decay, locks cell structure to dramatically reduce swelling and shrinking, and produces a warm chocolate-brown color throughout the board (not just on the surface).
Performance: Class 2 durability rating. Typical service life of 30–50 years uncoated, 50–80 years with a maintenance coating. Dimensional stability in humidity swings is roughly 40% better than untreated cedar (per Lunawood ThermoWood technical specifications).
Best for: Contemporary builds, Lake Washington waterfronts, and Eastside hillside homes where the architect wants warm wood tone without tropical-hardwood sourcing concerns. Lunawood’s signature ages to silver-gray within 12-18 months of UV exposure unless sealed.
Accoya — Acetylated Radiata Pine
$28–$42/sqft installedWhat it is: Plantation-grown radiata pine modified via acetylation — acetic anhydride permanently bonds to the wood’s cell walls at the molecular level. This isn’t a treatment that can leach or wear off. The wood’s chemistry is permanently altered.
Performance: Class 1 durability (highest rating issued). Manufacturer-backed 50-year warranty above ground, 25-year warranty in ground contact. Dimensional stability matches teak and exceeds most tropical hardwoods. Used on ship decking and windows that flex 100,000+ cycles.
Best for: Coastal exposures (Anacortes waterfront, Mercer Island lake-facing), architecturally demanding jobs where dimensional movement can’t be tolerated, and clients who want the longest warranty available in any wood product. Takes paint and stain exceptionally well — more stable than cedar under finish.
Charred-wood siding now has its own dedicated page — installed Seattle pricing ($38–60/sq ft with the required rainscreen), the Pioneer Millworks species and char levels we install, the accent strategy most clients choose, and our real Mercer Island project.
See the full shou sugi ban guide — cost, options & how we build it →
How We Install Premium Wood Siding
Premium wood deserves premium installation. The six-step GP General Corp process is the same rigor we use on every job — with premium-wood-specific detailing.
- Permit + wall-assembly assessment. We file the building permit with the City of Bellevue / Medina / Mercer Island and coordinate HOA design review where required. Most Eastside HOAs require a material sample board and warranty documentation for Shou Sugi Ban approval.
- Tear-off and substrate inspection. Every square foot of sheathing is inspected for rot, saturation, or structural deficiency. Premium wood is installed over new or confirmed-sound plywood only.
- Benjamin Obdyke HydroGap Drainable WRB. Our standard drainable weather-resistive barrier. For premium wood we always add a ventilated rainscreen furring layer on top (minimum ½” air gap) to give the wood maximum drying time — critical for 50+ year service life in PNW humidity.
- Flashings at every transition. Head flashings, kick-outs, step flashings, chimney counter-flashing, deck ledger pan flashing. All fasteners in contact with premium wood are stainless (Type 304 minimum, 316 on saltwater elevations).
- Board installation to manufacturer spec. Lunawood and Accoya are installed to Finnish / Dutch manufacturer guidelines (72-hour on-site conditioning, ¼” end gaps, cut-end sealer). Shou Sugi Ban requires pre-drilled fastener holes and handling that preserves the char layer.
- Final walk-through. We walk the property with you to make sure everything looks great and you’re happy with the final result. It’s a 20-point walk: caulk lines, paint touchups, downspout reattachment, gutter reset, and site cleanup.
Cost Comparison — Installed, Seattle Area
See full siding cost breakdown across all materials →
All ranges are installed with HydroGap WRB, ventilated rainscreen, stainless fasteners, and standard flashing detail. Pricing excludes permits and HOA submission fees.
| Material | Installed (per sqft) | Typical Warranty | Expected Service Life |
|---|---|---|---|
| James Hardie HardiePlank HZ10 | $14–$22 | 30 years product | 40–50 years |
| Western Red Cedar (clear) | $16–$28 | None standard | 20–30 years |
| Lunawood Thermally Modified | $22–$32 | 10–15 years coating | 30–50 years |
| Accoya Acetylated Wood | $28–$42 | 50 years above-ground | 50+ years |
| Shou Sugi Ban (Gendai) | $38–$50 | None standard | 80+ years |
| Shou Sugi Ban (Suyaki) | $48–$60 | None standard | 80–100 years |
Ranges reflect typical 1,800-3,000 sqft exterior install jobs. Complex geometries, tall elevations requiring scaffolding, or premium accent-only applications (small square footage) run higher per-sqft.
Premium Wood Siding FAQ
Which premium wood lasts longest in Seattle’s wet climate?
How does premium wood pricing compare to James Hardie?
Do I need HOA approval for Shou Sugi Ban or Lunawood?
Are these materials fire-code compliant in WSEC zones?
What’s the lead time on premium wood materials?
Can you mix Hardie with Premium Wood as an accent?
Ready to talk premium wood for your project?
Send us the architect’s drawings, scope, or a rough address — we’ll walk you through Lunawood, Accoya, or Shou Sugi Ban options specific to your site, orientation, and HOA environment. No pressure, no sales pitch. Just a straightforward conversation about which material is the right fit.
Request Premium Wood Quote