Ask House Spouse · Exterior & Weatherproofing · Decks & Outdoor Structures
How often should a deck be stained or sealed in the PNW?
Short answer
Semi-transparent stain lasts 2–3 years on a PNW deck; solid stain lasts 4–6 years; clear sealer lasts 12–18 months. Whichever you use, plan on a full clean and re-coat schedule and stick to it — a deck that's gone gray from neglect needs more than a re-coat, it needs board replacements first.
What kills PNW decks
Moss, standing water, and UV — in that order. Horizontal boards catch and hold moisture; south-facing exposures burn the finish; north-facing exposures grow moss. Cleaning matters more than the stain brand.
The right sequence
1) Clean with a dedicated deck cleaner (not just pressure wash — that furs the wood). 2) Neutralize with a brightener. 3) Let it dry 48 hours. 4) Sand any raised grain. 5) Stain. Skipping steps 1–2 is why re-stains fail in a year.
When to replace boards first
Screwdriver test again: any board that dents needs replacement before restaining. Deck boards are $3–$8 per linear foot for pressure-treated, more for cedar or composite. Handyman scope for straight replacement; larger structural repairs (joists, ledgers) sometimes call for a contractor.
What we see on Home Health Assessments
Around 74% of PNW roofs we assess show active moss establishment — accelerates shingle wear by an estimated 3–5 years if untreated.
Caught early on assessment: $220–$650 · Left until failure: $3,500–$22,000
Based on real experience across Snohomish and King County, exterior & weatherproofing issues like this are among the ones homeowners most often miss until they become expensive. Our Home Health Assessment catches them early — while they're still a maintenance item, not a repair.
How the Home Health Assessment worksServices we'd bring to this job
Where we handle this
We answer this question on real Home Health Assessments across Snohomish and King County.
Related questions
Exterior & Weatherproofing · Siding & Exterior Paint
How do I know if I have wood rot in my siding or trim?
Take a screwdriver and press firmly (not hard) against suspect wood — mainly the bottom edge of trim, corner boards, and any spot with peeling paint. Sound wood resists; rotten wood dents or crumbles. In the PNW, rot almost always starts at horizontal surfaces or trim-to-siding joints where water sits.
PNW Seasonal · Spring Cleanup
How do I remove moss from my roof safely in the PNW?
Don't pressure-wash a shingle roof — you'll shorten its life dramatically. Instead, apply a zinc-sulfate-based moss killer in dry weather, let it work for 1–3 weeks, then gently brush loose moss off with a soft roof broom or leaf blower. Install zinc strips along the ridge for long-term prevention.