A structured maintenance program significantly extends the life of exterior cedar. Canadian homeowners face marked seasonal transitions that call for targeted work at specific times of year.
Spring: inspection and preparation
Snowmelt is the best time to assess overall wood condition after winter. Damage from frost, water expansion in cracks, or snow load is visible from mid-March in most provinces.
Spring inspection
- Check for new cracks or splinters on boards
- Inspect wood-to-metal contact for rust migrating into the grain
- Test protection by pouring a few drops of water: if absorbed in under a minute, treatment is needed
- Examine post bases and areas in contact with soil or masonry
- Identify boards lifted or sprung after winter thermal movement
Spring cleaning
After inspection, deep cleaning removes deposits accumulated over winter: decomposed leaves, de-icing salt residue (never apply salt directly to wood), and early mould.
Diluted sodium percarbonate cleaning is effective for neutralizing mould without damaging cedar fibres. Let it act for 20 minutes, then rinse thoroughly.
Summer: treatment and protection
May through August is the ideal window for applying protective products in Canada. Conditions are usually favourable: moderate to warm temperatures, acceptable relative humidity, and frequent dry days.
Renewal sanding
If the previous treatment has flaking areas or the wood has raised fibres, light sanding at 80–120 grit is enough to prepare the surface. For surfaces not treated in several years, more aggressive sanding may be needed.
Always sand with the grain. Cross-grain sanding leaves visible marks after product application.
Summer treatment application
Choose a day with no rain forecast for the next 24 to 48 hours. Temperature should be above +10°C and below +30°C. Avoid strong wind days that dry the product too quickly before penetration.
Fall: preparing for winter
September through October is critical for regions with harsh winters. Treatment applied in fall protects wood during freezing months.
Pre-winter check
- Re-inspect sensitive areas identified in spring
- Fill cracks with an oil- or natural-resin-based filler compatible with cedar
- Apply touch-up treatment to worn areas without waiting for a full cycle
- Clean gutters and channels next to cedar structures to prevent overflow onto wood
Final work before frost
Ensure all product applications are finished before temperatures regularly drop below 5°C. Most protective products need at least 3 to 5 days above freezing to cure properly.
Winter: observation and documentation
In winter, work on exterior wood is limited. Snow on a deck or fence partly shields wood from extreme temperature swings, provided it does not stay piled against the wood for weeks.
What to watch for
- Snow and ice buildup at post bases
- Ice dams suggesting a drainage problem above
- Board distortion after rapid freeze-thaw episodes
Visual documentation
Photograph problem areas in winter for reference during spring inspection. This helps track damage year over year and prioritize work.
Summary of annual tasks
- March–April: full inspection, cleaning, replacement of damaged elements
- May–August: sanding if needed, main treatment application
- September–October: check-up, crack filling, touch-up treatment
- November–February: visual monitoring, documentation
Last updated: May 1, 2026