A well-protected Merbau deck not only looks great but also stands up to the elements, preventing damage from UV rays, moisture, and general wear. Topcoating your deck with a quality decking oil or stain enhances the natural beauty of Merbau timber while extending its lifespan. Here’s how to properly topcoat your Merbau deck and keep it looking its best.
Safety tip: Always wear the appropriate safety equipment (safety glasses, gloves, ear muffs and a mask, for example) and always follow the instructions for the product or equipment.
STEPS
1. Prepare the deck
On a clear day with no rain expected, clear the deck of all outdoor furniture, planters, barbeques, and other obstructions. Give it a thorough sweep to remove dust, leaves, and debris. Focus on the areas between the boards, and in the corners as these areas tend to trap more buildup.
2. Clean the deck
If your deck has any dirt, grease, or mould, clean it using a timber deck cleaner and a stiff-bristled brush. Rinse it thoroughly with a garden hose or pressure washer on a low setting, and allow it to dry completely—this can take 24 to 48 hours depending on the weather.
If your Merbau deck has a rough or weathered surface, give it a light sand using fine-grit sandpaper (80-120 grit). This helps smooth out imperfections and allows the topcoat to absorb more evenly. After sanding, sweep or vacuum the dust off to ensure a clean surface for application.
3. Choose the right topcoat
Once you're ready to begin, tape off any areas where you want to avoid applying the topcoat, such as edges near walls or pillars. Next, choose a high-quality decking oil or stain suitable for hardwoods like Merbau. Look for a UV-resistant, water-repellent product that nourishes the timber while providing a durable finish. If you're unsure, opt for a natural oil-based product, as it penetrates deeply without forming a surface film. Before application, stir the decking oil or stain thoroughly to ensure an even consistency. If using a tinted product, test it on a small, inconspicuous area to confirm the colour meets your expectations.
4. Apply the topcoat
Then, using a high-quality decking brush or lambswool applicator, apply the first coat of topcoat evenly along the length of the boards. Work in sections to avoid lap marks, and make sure the product penetrates the timber without pooling. If using an oil-based topcoat, wipe off any excess after 10-15 minutes to prevent sticky spots.
5. Brush the edges
Once you've applied the topcoat to the top surface of the deck, use a brush to carefully coat the edges. This ensures a clean, even finish, especially in areas where a roller or applicator may have missed. Brushing the edges also helps prevent drips and buildup, giving your deck a professional, polished look.
6. Apply the second coat
Let the first coat dry according to the manufacturer’s instructions, usually between 4 to 24 hours, depending on the product and weather conditions. Avoid walking on the deck during this time to prevent dust and debris from settling into the finish.
Once the first coat is dry, apply a second coat using the same technique. This additional layer enhances durability and ensures a consistent, well-protected finish. For best results, follow the grain of the timber and avoid over-application.
7. Let the deck cure
After applying the final coat, allow the deck to cure fully before placing furniture back or walking on it. This can take anywhere from 24 to 72 hours, depending on humidity and temperature. During this time, keep the deck free from water and heavy foot traffic to ensure a flawless finish.
8. Ongoing maintenance
To keep your topcoat in peak condition, regularly sweep your deck to prevent dirt and debris from accumulating. Clean spills immediately to avoid staining, and reapply a fresh coat of oil or stain every 6 to 12 months, depending on exposure to the elements. Avoid using harsh chemicals or high-pressure washing, as they can strip the protective finish. By following these steps, you’ll keep your Merbau deck looking rich, resilient, and ready to take on whatever the outdoors throws at it.
