1. Never pressure wash
A pressure washer blasts out the soft summer grain between the hard grain lines, leaving a ridged, grooved deck that then holds dirt worse than before.
It also lifts caulking edges and drives water under the seams. One afternoon with a pressure washer can cost years of deck life.
2. Wash across the grain, gently
Wet the deck, apply a mild cleaner and scrub lightly ACROSS the grain with a soft brush. Scrubbing along the grain digs out the soft wood.
Salt water is genuinely good for teak — it keeps the wood slightly damp and discourages growth. A rinse with seawater and a soft brush is often all a deck needs.
Rinse thoroughly with fresh water afterwards so no cleaner residue is left sitting in the seams.
3. Check the caulking and plugs
Run a thumbnail along each seam. Caulking that has lifted at one edge lets water down to the substrate and the fastenings below — cut it out and re-caulk that section before it spreads.
Look for missing or proud plugs over the screw heads. A missing plug means water straight onto a fastening; chisel the recess clean, glue in a new teak plug with the grain aligned and pare it flush once cured.
4. Measure what you have left
Teak decks are typically laid at 10-12 mm. Once the wood has worn down close to the screw heads or below about 4 mm, cleaning is no longer the question — the deck needs relaying.
Check the depth at the seams with a thin ruler once a season so the decision is not a surprise.
5. Oil, seal, or leave it bare
Leaving teak bare to weather silver-grey is the lowest maintenance option and does the wood no harm at all. Most professional advice on working boats is to do exactly this.
Oil looks warm and rich but needs redoing every few months, and in a damp climate it can encourage black mould growth.
Sealers last longer than oil but wear patchily and are awkward to touch up. Whatever you choose, apply thin and wipe off any excess before it goes tacky.