Capped composite handles constant Pacific Northwest moisture with the least maintenance, while cedar offers warmth that composite cannot match if you will re-finish it every year or two. The detail almost nobody mentions: composite decking is not structural, so it usually needs tighter joist spacing and closer stair stringer spacing than wood. If your deck was framed for wood, swapping the boards alone is often not an option.
"We're just getting quotes right now — composite or wood, which one actually holds up here?" We hear some version of that on almost every deck visit lately. One Kirkland homeowner put it simply: her old boards were twisting, curling, coming up, and she wanted to know which material would keep the deck feeling solid for the next twenty years, not just the next five.
Our climate is a strange combination for decking. From October through May, we get months of slow, steady moisture — the kind that soaks into end grain, sits in board gaps, and quietly starts rot where fasteners penetrate the wood. Then July and August arrive, boards dry out fast, and direct sunlight on a south- or west-facing deck means it gets really hot. That wet-dry cycling is what causes cupping, checking, and splitting in wood, and it's also what causes cheap composites to fade or chalk.
Neither material gets a free pass here. Cedar handles moisture better than most woods but needs regular finishing. Pressure-treated fir is affordable and durable structurally, but as a walking surface it splinters and moves. Composites like TimberTech and Trex shrug off the rain, but they have their own quirks in heat and — this is the part nobody mentions — in how they need to be framed.
Here's what surprises people. Composite decking is not structural. A cedar 2x6 has real stiffness across a span; a composite board does not. That means composite usually requires tighter framing — joists at 16 inches on center for straight runs, often 12 inches on center for diagonal patterns, and manufacturers call for closer stringer spacing on stairs than a wood tread would need.
So if you're re-decking an older deck that was framed for wood, "just swap the boards" often isn't an option. On a recent visit, a homeowner had been told by another contractor that his composite steps would need extra stringers, and he asked us straight out: "How much does that add on to the cost?" The honest answer is that it depends on what's under there. Sometimes it's adding a stringer or two and sistering a few joists. Sometimes the existing framing is rotted or deteriorated, and if there is rot, it all has to go — you don't put brand-new composite over compromised structure.
This is also why stairs deserve special attention. Steps are where people feel a deck first. If a stair feels unstable to go down, no surface material fixes that — the fix is in the stringers, the brackets, and the attachment. One homeowner told us his wife was always dreading those steps. After the rebuild, his words were "a lot safer, and a lot happier." That came from the framing, not the boards.
Cedar has a warmth composite genuinely can't match, and plenty of people know it. One homeowner we visited had priced out composite carefully and chose to keep the beauty of wood — eyes open about the maintenance. That's a completely valid call if you're willing to clean and re-finish every year or two.
Wood is also more forgiving on existing framing, easier to repair board-by-board, and simpler to color-match — if you want the deck the same shade as the house trim, stain gives you options composite doesn't. The trade-off: in our climate, some movement is inevitable. Boards will check and gray, and skipped maintenance shortens the lifespan considerably.
Rather than quote numbers that vary job to job, here's what moves the price on Eastside deck projects:
Usually, yes. Composite treads span less distance than wood before they flex, so manufacturers specify closer stringer spacing on stairs and tighter joist spacing on the deck surface. If your deck was framed for wood, expect some framing additions before composite goes down.
Sometimes — if the framing is sound and the joist spacing meets the manufacturer's requirements. We inspect for rot, check spacing, and add joists or stringers where needed. If the structure is compromised, it has to be corrected first, because composite boards will outlast bad framing and hide the problem.
Capped composite handles constant moisture with the least maintenance, which is why it's popular here. Cedar performs well too, but only with regular cleaning and finishing. Pressure-treated wood is the budget option and works fine structurally, though it's the least attractive walking surface over time.
It depends heavily on maintenance and exposure. Well-maintained cedar can serve for decades; neglected cedar in a wet, shaded spot deteriorates much faster. Quality composite generally lasts longer with far less upkeep, provided the framing underneath stays healthy.
The material choice matters, but the structure decides whether your deck feels solid for the long haul. If you're on the Seattle Eastside — Kirkland, Bellevue, Redmond, and the surrounding areas — Roof4Life will come out, take an honest look at your framing and stairs, and walk you through both options with no pressure. Call us at (425) 207-3500 to schedule a free inspection.
No-obligation, detailed written estimate from Roof4Life. Serving Kirkland, Bellevue, Redmond, Sammamish, Issaquah & the entire Seattle Eastside since 2012. Rated 4.9 stars across 74 reviews.
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