Seattle One Product, One Standard
Most exterior contractors in the Seattle area will install whatever a homeowner wants: vinyl, LP SmartSide, cedar, primed spruce, fiber cement from a handful of manufacturers. We don't. We install James Hardie fiber cement siding, full stop. This isn't a marketing gimmick or a manufacturer kickback — it's a standard we set after years of tearing old siding off King County homes and seeing which products actually held up to our weather and which ones didn't.
This page explains the reasoning in plain terms: what fiber cement is, why our climate is unusually hard on siding, how Hardie's product line is built for exactly these conditions, and what a correctly installed system looks like. We're not going to tell you every other product is junk — some of them have real strengths. We're going to tell you why, after weighing those trade-offs against what a Seattle house actually deals with, we stopped offering alternatives.
What Makes Seattle Siding Different
Siding failure here rarely looks dramatic. It's slow: moisture creeping behind panels, moss colonizing north-facing walls, paint chalking and peeling years ahead of schedule, seams that swell and separate. Three things drive most of it.
Driving Rain
Seattle doesn't get the heaviest annual rainfall in the country, but we get a lot of low-intensity rain pushed sideways by wind off the Sound, and it falls on the same walls for months at a stretch. Products that rely on paint film or a factory coating with poor moisture resistance start showing it within a few winters.
A Long Moss Season
Shade, humidity, and mild temperatures mean moss and algae have close to nine months a year to establish themselves on siding, especially on the north and west exposures common on lots shaded by mature Douglas fir. Wood-based products are especially vulnerable because moss retains moisture directly against a surface that can rot.
Salt Air Near the Sound
Homes closer to Puget Sound and the sound-adjacent neighborhoods deal with a low but constant level of salt-laden air, which accelerates corrosion of fasteners and trim and degrades some coatings faster than manufacturers' inland test data would suggest.
None of this is exotic weather. It's just relentless, and relentless is what breaks down marginal products over a 10-15 year window instead of the 30-50 year window homeowners expect from a "permanent" siding job.
Why We Stopped Installing the Alternatives
We didn't reach this standard by reading a brochure. We reached it by servicing houses.
Vinyl
Vinyl is inexpensive and low-maintenance in the sense that it doesn't need paint. But it's a thin plastic product that expands and contracts significantly with temperature swings, which opens seams over time, and it has no real fire resistance — it softens and deforms at relatively low heat. In wind-driven rain it depends heavily on correct house-wrap and flashing detail behind it, because the vinyl itself isn't a real water barrier, just a rain screen. We still see 15-year-old vinyl jobs with warped panels and gapped corners.
LP SmartSide and Other Engineered Wood
Engineered wood siding has improved a lot from the OSB siding failures of the 1990s, and LP's current product is a better piece of engineering than its predecessors. But it's still a wood-strand product with a resin binder, and any wood-based siding is only as good as the paint film and caulking protecting its edges — especially cut ends and butt joints, which are the first place moisture gets in. In a climate with our rain load and moss season, that's a maintenance obligation that doesn't go away, and if a crew misses caulking a single cut edge, that's where the rot starts.
Cedar and Primed Spruce
Real wood siding looks great and plenty of older Seattle homes still wear it well because it was maintained religiously — recoated on a strict cycle, kept free of vegetation contact, flashed meticulously. That maintenance burden is the honest trade-off: wood siding is a recurring project, not a one-time install, and most homeowners underestimate how often it actually needs attention in our climate.
Other Fiber Cement Brands (Cemplank, Allura, etc.)
These are legitimate fiber cement products, chemically similar to Hardie's. Our objection isn't to the material category — it's that we've standardized our crews, our fastening schedules, our flashing details, and our warranty relationships around one manufacturer's engineering and factory finish system, and we'd rather be excellent at installing one product correctly than adequate at installing several.
What Fiber Cement Actually Is
James Hardie siding is made from Portland cement, sand, and cellulose fiber, cured under pressure and heat. The result is a rigid, dense board that doesn't burn, doesn't absorb moisture the way wood does, doesn't expand and contract with temperature the way vinyl does, and isn't attractive to insects. It's heavier and more labor-intensive to install than vinyl or engineered wood, which is part of why it costs more — but the material itself is doing more work to protect the house.
Engineered for Climate, Not Just Painted for Looks
Hardie makes region-specific formulations under its "HZ5" and "HZ10" engineered-for-climate system. The HZ5 line is formulated for wetter, more variable climates like ours, with moisture and freeze-cycle performance tuned differently than the HZ10 formulation sold in hot, dry, or hurricane-prone regions. That distinction matters more than most homeowners realize — it's the difference between a product tested against Seattle's actual weather pattern and one tested against Phoenix's or Miami's.
ColorPlus Factory Finish
The other half of the engineering is the finish. ColorPlus is a multi-coat, baked-on finish applied in a factory under controlled conditions, not brushed or sprayed on a jobsite where wind, temperature, and humidity all affect how paint cures. It resists fading and chalking far longer than field-applied paint, and because it's factory-cured, it's ready for weather exposure immediately rather than needing a dry window after installation — which matters on a job site where a dry multi-day stretch isn't guaranteed.
The Product Lines and Where They Fit
Hardie isn't one product — it's a system of profiles that cover different parts of a house. We spec the line based on the home's style and exposure, not a one-size-fits-all approach.
| Product | What It Looks Like | Typical Use |
|---|---|---|
| HardiePlank | Traditional horizontal lap siding, several plank widths and textures | Primary field siding on most home styles |
| HardiePanel | Large vertical sheet, smooth or textured | Modern facades, accent walls, board-and-batten look |
| HardieShingle | Staggered or straight-edge shingle profile | Craftsman and cottage-style homes, gable accents |
| HardieTrim | Smooth or textured boards for corners, fascia, window and door surrounds | Finishing detail work around openings and edges |
| HardieSoffit | Vented or non-vented panel for eaves | Attic and roof ventilation, moisture control at the roofline |
What Correct Installation Actually Involves
Fiber cement is a forgiving material chemically, but it's unforgiving of sloppy installation. Most of the fiber cement failures we get called to inspect on other contractors' work trace back to installation shortcuts, not the product itself. Correct installation on a Seattle home means:
- Proper weather-resistant barrier and flashing behind every panel, with special attention to window and door head flashing where most water intrusion actually starts
- Correct fastener type and placement per Hardie's published fastening schedule — not whatever nail gun setting is fastest
- A minimum clearance gap at the bottom of the siding above grade, decks, and roof lines so panels aren't wicking standing moisture
- Caulked and primed cut ends where field cuts expose the substrate, sealed the same day as the cut
- Rain screen or drainage gap detailing appropriate for our high-rainfall exposure, not just a direct nail-to-sheathing install
- Correct joint treatment at butt seams so panels aren't relying on caulk alone for years of movement
We follow Hardie's published installation instructions to the letter, partly because it's the right way to build, and partly because deviating from them can void the manufacturer's warranty — a detail some lower-bid contractors don't mention until it's too late.
Warranty Structure
Part of why we can stand behind this work is that Hardie backs it with a warranty structure that's unusually strong for the exterior products industry.
| Coverage | Term | Notes |
|---|---|---|
| HardiePlank/Panel/Shingle siding | Non-prorated, multi-decade coverage | Covers manufacturing defects; specific term varies by product and region — confirmed at estimate |
| ColorPlus finish | Separate finish warranty | Covers finish integrity (fading, peeling, chipping) apart from the substrate itself |
| Transferability | Transfers to a new owner | A real asset if you sell the home during the coverage period |
| Labor/workmanship | Covered by our installation warranty | Separate from Hardie's material warranty; ask us for current terms |
The exact term lengths and conditions are published by Hardie and we'll walk through the current documentation at your estimate rather than quote numbers here that could be out of date by the time you read this.
Cost Factors Worth Understanding
Fiber cement costs more upfront than vinyl and usually more than engineered wood, largely because of material weight, cutting requirements (fiber cement dust requires proper cutting tools and dust control), and labor time. Here's what actually drives the number on a King County job:
| Factor | Why It Matters |
|---|---|
| Home size and wall complexity | More corners, dormers, and trim detail mean more cutting and labor time |
| Tear-off vs. overlay | Removing old siding down to sheathing adds cost but lets us fix hidden moisture damage and install proper flashing |
| Product line mix | Combining plank, panel, and shingle profiles for architectural detail costs more than field siding alone |
| Color and texture | ColorPlus colors and specialty textures are priced differently than standard primed boards |
| Access and site conditions | Steep lots, mature landscaping, and multi-story walls common in Seattle neighborhoods affect scaffolding and labor |
We won't quote a blanket price range here because every King County home is different, but we will give you a detailed, itemized estimate that shows exactly what you're paying for.
Is This Actually the Right Call for Your Home
We're not going to pretend fiber cement is the right answer for every single situation on earth — there are historic restoration cases and niche budget scenarios where it isn't. But for a standard Seattle-area home dealing with our rain, our moss season, and our salt air proximity to the Sound, we've made our decision after years of doing the tear-offs on the products that didn't hold up. If you want to see how this would actually work on your house — product line, color, and a real itemized number — we're glad to come take a look and put together a free, no-pressure estimate.