Seattle Siding A Straight Answer Before You Read Further
Homeowners ask us this a lot, usually after getting a bid from another contractor: "Why don't you install LP SmartSide?" It's a fair question. LP SmartSide is a legitimate, widely used product, and plenty of licensed, competent contractors install it well. We're not here to tell you it's junk. We're here to explain why we made a business decision years ago to install James Hardie fiber cement exclusively, and why that decision has held up through everything Seattle's climate throws at a house.
This isn't a takedown. It's the reasoning we'd give you in person if you asked, laid out so you can weigh it for yourself.
What LP SmartSide Actually Is
LP SmartSide is an engineered wood siding product. The core is made from wood strands bonded with resins under heat and pressure, similar in concept to oriented strand board (OSB), then finished with a resin-saturated overlay and a factory primer or pre-finished coating. It comes in lap boards, panels, and trim, and it's manufactured to be lighter and easier to handle than fiber cement.
Because the core material is wood-based, it machines and installs a lot like traditional wood siding — contractors who came up installing cedar often find it a comfortable transition. That familiarity is part of why it's popular with some crews.
What LP SmartSide Gets Right
Credit where it's due:
- It's noticeably lighter than fiber cement, which can speed up installation and reduce crew fatigue on multi-story homes.
- Modern LP SmartSide (the current "SmartSide 176" and related product lines) uses a treated strand technology and resin overlay that is a real improvement over the OSB-based hardboard sidings of the 1980s and 90s, which had well-documented moisture failures.
- It cuts and nails with standard woodworking tools, which some crews find faster to work with than fiber cement's specialized blades and dust control requirements.
- The price point is generally lower than fiber cement, which matters on tight budgets.
If LP SmartSide were a bad product across the board, we wouldn't feel the need to explain ourselves this carefully. It's not bad. It's a different set of trade-offs, and those trade-offs matter more in some climates than others.
Why Wood-Based Cores and Seattle's Climate Don't Mix Well, in Our Experience
The Core Material Is Still Wood
No matter how well-engineered the strand core is, or how good the resin saturation is, the base material is organic wood fiber. Wood fiber's failure mode, when moisture gets past a coating or a seam, is swelling, delamination, and eventually rot at the edges — especially cut ends, corners, and butt joints where the factory coating doesn't reach. Fiber cement doesn't have that failure mode at all, because there's no wood fiber to absorb water in the first place.
Seattle-Specific Moisture Exposure
King County isn't the wettest climate in the country, but it is one of the most persistently damp. Seattle sees driving rain off Puget Sound, long stretches of low-intensity drizzle that keep exterior surfaces wet for days at a time, and — closer to the water — salt-laden air that accelerates coating breakdown on almost any exterior material. Add in a moss and algae season that can run eight or nine months out of the year in shaded, north-facing exposures, and you get a climate that keeps siding surfaces damp and organically active for most of the year. That's a tough environment for any product whose core is engineered wood.
Field-Joint and Cut-End Sensitivity
Every LP SmartSide installation involves field cuts — around windows, at corners, at butt joints between boards. Every one of those cuts exposes raw core material that has to be sealed correctly with manufacturer-approved caulk or edge sealant, every time, or that spot becomes a moisture entry point. Fiber cement cut edges are far more forgiving; the material itself doesn't swell or rot even if a cut edge goes unsealed for a while. With LP SmartSide, installation quality at every single joint is the entire ballgame for long-term performance. We don't like betting a homeowner's siding job on every crew member remembering to seal every cut, on every elevation, for years to come.
LP SmartSide vs. James Hardie Fiber Cement: The Comparison
| Factor | LP SmartSide | James Hardie Fiber Cement |
|---|---|---|
| Core material | Engineered wood strand, resin-treated | Cement, sand, and cellulose fiber — non-organic |
| Moisture/rot risk | Low if intact, rises sharply at unsealed cuts or coating damage | Does not rot; unaffected by standing moisture |
| Fire performance | Combustible, wood-based core | Non-combustible, Class A fire rated |
| Factory finish | Primed or pre-finished; field caulking of joints required | ColorPlus baked-on finish, factory-warranted color |
| Weight | Lighter, easier handling | Heavier, requires proper fastening technique |
| Typical manufacturer warranty | 5-year workmanship + limited product warranty, varies by line | 30-year non-prorated limited warranty on siding; separate ColorPlus finish warranty |
| Pest resistance | Treated, but wood-based composition still relevant to insects | Not a food or nesting source for insects |
| Long-term maintenance | Periodic recaulking of joints and cut ends, repainting cycles | Minimal — factory finish resists fading and moisture |
Installation Sensitivity Is the Real Issue
Every siding product performs differently depending on how well it's installed, but the margin for error is not the same across products. Fiber cement is fairly tolerant of small installation imperfections because the material itself doesn't degrade from moisture exposure. Engineered wood siding products are much less tolerant — a missed sealant bead, a fastener driven at the wrong angle, or clearance that's too tight at the bottom of a wall can turn into a moisture problem within a few wet seasons, not decades.
We install crews of a consistent size, trained on one product system, running one set of installation standards. Standardizing on James Hardie lets us hold every job to the same detailing standard — flashing, clearances, fastener patterns, joint treatment — without needing a second set of moisture-sensitive best practices layered on top for a different product. That consistency is worth more to us, and to the homeowners we work for, than the labor savings of a lighter board.
Warranty Structure Matters More Than It Looks
Warranty length is one thing; warranty structure is another. James Hardie's fiber cement siding warranty is a long-term, non-prorated limited warranty that's transferable to a new owner if the home sells — a real factor in resale, especially for the kind of older King County housing stock where a buyer's inspector will ask direct questions about siding age and warranty status. Engineered wood siding warranties are typically shorter and more heavily conditioned on maintenance compliance — meaning the homeowner has to keep up with caulking, painting, and inspection on a defined schedule to keep the warranty valid. That's not a knock on the product; it's just a different level of ongoing homeowner responsibility, and we'd rather not sell a warranty that depends on someone remembering to recaulk trim every few years.
Why We Standardized on James Hardie
We made the call to install James Hardie exclusively because it removes the variables that cause the most callbacks in this climate: no wood core to swell or rot, a factory-baked finish that doesn't need field painting, a fire-resistant material that adds real value in a region where wildfire smoke seasons have made homeowners more fire-conscious, and a warranty that doesn't put the burden of upkeep on the homeowner to stay valid. Hardie's HZ5 product line is engineered specifically for climate zones with high moisture exposure, which describes Seattle and the rest of King County well. When we stand behind a job for the long haul, we want the material doing the least amount of complaining possible over the next thirty years.
What to Ask Before You Choose a Siding Material
- Ask what the core material is made of, not just the brand name — wood-based, cement-based, and vinyl all age differently.
- Ask what happens at cut ends and field joints, and who is responsible for sealing them correctly.
- Ask whether the warranty is prorated, and what maintenance it requires to stay valid.
- Ask whether the product is rated for your specific exposure — south/west sun, shaded north walls prone to moss, or areas closer to salt air.
- Ask how the contractor handles flashing and clearance details, since those matter more than the brand of board on the wall.
- Ask for the manufacturer's own installation guide and compare it to what the crew is actually planning to do.
The Bottom Line
LP SmartSide isn't a scam product, and a well-installed job can perform reasonably well for years. But given Seattle's rain, the long moss season on shaded exposures, and the salt air closer to the Sound, we decided the risk profile of a wood-based core wasn't one we wanted to put our name behind for the long term. James Hardie fiber cement gives us a material that doesn't rot, doesn't need repainting, carries a strong transferable warranty, and holds up to correct installation without the same margin-for-error problems. That's the trade we're comfortable making, and it's why it's the only siding system we install.
If you're comparing siding materials for a home anywhere in Seattle or King County, we're happy to walk your specific house, look at your exposure, and give you an honest read on what we'd recommend — no pressure, no hard sell. Reach out for a free estimate using the form below.