Composite Decking Maintenance Guide: Caring for Your Deck Year-Round
The Good News First
Compared to timber, composite decking is gloriously low-maintenance. There's no sanding, no oiling, no staining, no varnishing. But 'low-maintenance' isn't 'no-maintenance' - a small amount of care keeps your deck looking new for 20+ years.
Spring (March-May)
Clear winter debris with a stiff broom. Hose down the boards with plain water to loosen surface grime. For any algae or grime build-up from winter, use warm soapy water with washing-up liquid and a soft-bristle brush, then rinse thoroughly. This is also the time to check fixings, joists, and step nosings for any loose elements.
Summer (June-August)
Sweep weekly to keep dust, pollen, and food crumbs off the surface. Wipe up food and drink spills as they happen - sugary drinks, oily sauces, and red wine are not stains for capped composite, but standing in heat they can become harder to remove if left for days. Move planters and BBQs occasionally to prevent uneven sun-fading patterns in the first year or two.
Autumn (September-November)
The single most important season for composite decking. Leaves are the biggest problem - they retain moisture against the surface and feed algae growth. Sweep at least weekly during leaf fall, and clear any leaves trapped in board grooves. A jet wash on a low setting (under 1,500 PSI, fan tip, 30cm from the surface) clears the boards beautifully at the end of autumn.
Winter (December-February)
Keep the deck clear of standing snow if possible - use a plastic snow shovel only (never a metal blade, which scratches the cap). Rock salt is fine on composite decking, but rinse the boards in spring to remove residue. Avoid leaving rubber mats, plastic sheeting, or anything that traps moisture against the boards for long periods.
Cleaning Common Stains
Grease and food: warm soapy water with a soft brush. Red wine, coffee, fruit juice: act quickly, then warm soapy water. Tree sap: a non-abrasive deck cleaner or diluted white vinegar. Mildew or algae: a composite-safe biocidal wash, scrubbed with a soft brush. Rust marks: oxalic acid-based deck cleaner, applied carefully.
What to Avoid
Wire brushes and steel wool - they scratch the protective cap. Pressure washing above 1,500 PSI or closer than 30cm - it can pit the surface. Bleach and acidic cleaners not formulated for composite. Sanding - never required, and it removes the protective cap layer.
Annual Inspection Checklist
Each spring, check: all fixings are tight, no joists feel soft or springy, drainage gaps between boards are clear, fascia boards are still in line, step nosings haven't loosened, and substructure timbers (if used) show no signs of rot. Address any issues immediately rather than waiting for next year.
