The Complete Guide to Cleaning, Restoring and Sealing Teak for Long-Lasting Results

Teak is one of the most beautiful and durable timbers you can use on boats and in the garden — but to keep it looking its best, it needs the right care. In this guide, we’ll walk you step-by-step through cleaning teak with a two-part teak cleaner and then protecting it with Semco Teak Sealer for a long-lasting, natural finish.

Step 1: Cleaning Teak with a Two-Part Teak Cleaner

Before applying any sealer, your teak must be properly cleaned. For light freshening, a gentle soapy water wash may be enough. However, for deeper cleaning and restoration, a two-part teak cleaner system is ideal.

How Much Cleaner Do You Need?

Two-part teak cleaner is supplied as a full concentrate and must always be diluted with water.

As a general guide:

• 1 litre of each part cleans approximately 8–12m² of teak (depending on weathering and staining).
• Teak garden furniture: 1 litre of each part is often sufficient for a table and 4 chairs.
• Teak boat decks:
  • Boats up to 30ft – 1 litre of each part
  • 60ft boats – 3–4 litres of each part
  • Larger or heavily weathered boats may require more

Equipment Needed

Before starting, make sure you have:

• Waterproof gloves
• Eye/face protection (goggles or similar)
• Overalls or old clothing
• Plastic bucket
• Sponge or foam brush (avoid hard bristles)
• Long-handled brush (helpful for decks)
• Hose with fresh water supply (do not use a pressure washer)

⚠️ Important: Thoroughly wash brushes or sponges when switching between Part 1 and Part 2. The products will neutralise each other if mixed.

Key Cleaning Tips

• Avoid leaving Part 1 on painted or varnished surfaces.
• Rinse immediately (or as soon as possible) from any surfaces other than teak.
• Prolonged contact with aluminium can cause tarnishing — protect trims with grease or rinse regularly.
• Scrub diagonally to the grain to reduce fibre damage.
• Always keep the teak wet before and during cleaning. On hot days you may have to keep rinsing the teak to prevent drying.
• Never let the product dry on the surface.

Cleaning Instructions

For Badly Weathered or Stained Teak

1. Dilute Part 1 at 5:1 (5 parts water, 1 part cleaner).
2. Wet the teak and remove standing water.
3. Work in sections of about 1m², being careful not to kneel in the solution once applied to the teak surface.
4. Apply with a sponge and gently agitate.
5. Allow the area to darken to a uniform dark brown.
6. Rinse thoroughly with fresh water.
7. Repeat the process using Part 2 at the same 5:1 dilution.
8. The teak should lighten almost immediately to a uniform “nutty” brown.  This should happen almost immediately.
9. Rinse thoroughly, paying attention to metals and other delicate areas.
10. Allow to dry naturally to a straw colour.

For Lightly Weathered or Stained Teak

1. Dilute Part 1 at 10:1.
2. Follow the same process as above.
3. Repeat with Part 2 at 10:1.
4. Rinse thoroughly and allow to dry.

Drying Time Before Sealing

Before applying any sealer:

• Ensure the teak has been washed properly (either soapy water for light cleaning or two-part cleaner for deeper restoration).
• Allow 48–72 hours drying time after cleaning before applying Semco Teak Sealer.
• The wood must be completely dry before sealing.

Sealing damp wood can trap moisture and affect the finish.

Step 2: Applying Semco Teak Sealer

Once your teak is clean, dry, and back to a natural straw colour, you’re ready to apply Semco Teak Sealer.

Preparation

• Stir the tin thoroughly before starting.
• Continue stirring during application to ensure an even finish.

Proper mixing is essential for colour consistency.

Application Method

For best results:

• Use a foam brush or cloth, not a traditional paintbrush.
• This gives you better control.
• Helps avoid unsightly brush marks.
• Allows you to seal only the areas you want treated.

First Coat

• Apply evenly.
• The first coat will absorb quickly.
• Allow a couple of hours drying time.

Second Coat

• Apply on the same day for best results.
• Wipe off any excess as you go.
• Allow sufficient drying time before use.