Yellow Balau (Bangkirai) Decking Boards Dual Ribbed 25x145mm

The dual ribbed version of our Yellow Balau hardwood decking boards — ribbed on both faces with two different rib patterns, fully reversible. The same premium Bangkirai tropical hardwood as our smooth 21x145mm board, with the addition of a ribbed profile on both faces that channels water away from the surface and improves grip underfoot in wet conditions.

At 25x145mm, these boards are one of the most widely specified hardwood decking sizes in the UK — a face width that covers ground quickly, reduces board runs per square metre, and creates a bold, open deck aesthetic. The dual ribbed profile makes this board particularly well suited to any outdoor area where wet-weather grip is a priority: poolside decking, waterfront terraces, steps, exposed coastal decks, and commercial hospitality spaces.

Product Specifications

What Is a Dual Ribbed Decking Board?

A dual ribbed board is machined with a ribbed profile on both faces — each face carrying a different rib pattern. The board is fully reversible: install either face upwards depending on the texture and grip level you prefer. Both faces provide improved anti-slip performance compared to a smooth board, with the ribs channelling surface water away from underfoot contact points.

This makes dual ribbed Bangkirai decking the practical choice for any deck where wet-weather performance matters. Poolside areas, waterfront decking, exposed coastal terraces, steps, and commercial spaces with high footfall in all weathers are all well served by a ribbed profile. For projects where a clean, minimal appearance is the priority, our smooth Yellow Balau board is the alternative.

Yellow Balau (Bangkirai) — The Timber

Yellow Balau and Bangkirai are the same species — Shorea laevifolia from the Dipterocarpaceae family, native to the forests of Malaysia and Indonesia. Yellow Balau is the UK and Malaysian trade name; Bangkirai is the Indonesian and Dutch equivalent. Both are among the most popular tropical hardwood decking timbers sold in the UK, chosen for their combination of natural durability, hardness, and warm golden-brown appearance.

With a density of approximately 980 kg/m³ and a Janka hardness of around 1,600 lbf, Yellow Balau is one of the hardest and densest decking timbers available. This hardness translates directly into resistance to surface wear, denting, and the daily impact of heavy foot traffic — qualities that make it particularly suited to commercial decking applications alongside residential gardens and patios.

Its natural oil content gives it inherent resistance to rot, fungal decay, and insect attack, achieving a natural durability class of 1–2 without chemical preservative treatment. Historically used in marine construction, bridge building, and harbour works — environments far more demanding than UK garden decking — Yellow Balau hardwood decking is built to last decades in outdoor conditions.

Durability and Lifespan

Yellow Balau hardwood decking has an expected service life of 25 years or more in above-ground outdoor conditions. With regular oiling and maintenance, lifespans of 40 years and beyond are regularly achieved. Its resistance to the repeated wet-dry cycles of the UK climate is well established, and its interlocking grain structure keeps boards flat and stable where less dense softwood timbers would warp or cup over time.

The ribbed profile on this dual ribbed board also helps water drain from the deck surface rather than pooling, which further supports long-term performance by reducing the time the board surface spends saturated after rain.

Installation

These ribbed hardwood decking boards are face fixed. Pre-drilling pilot holes is essential — Yellow Balau is extremely dense and will split boards and shear screw heads without pilot holes. Use stainless steel A2 or A4 screws throughout; standard zinc-plated fixings corrode prematurely in contact with the natural tannins in Bangkirai and will stain the board surface. Leave a 5–6 mm gap between boards for drainage and seasonal movement.

Acclimate boards on site for a minimum of 48–72 hours before installation. Install on a well-ventilated subframe with joists at maximum 400mm centres for residential use, reducing to 300mm for commercial or high-traffic decks. Seal all cut ends immediately after cutting with a hardwood end-grain sealer or decking oil.

We stock stainless steel screws and hardwood decking oils suitable for Yellow Balau and Bangkirai decking.

Finishing and Maintenance

No treatment is required to maintain the structural performance of Yellow Balau decking. Left untreated, the boards will weather from golden-brown to silver-grey over approximately 12–18 months — a natural process that does not affect durability. To retain the warm original colour, apply a UV-stable penetrating hardwood decking oil before installation and reapply annually or as the surface demands. The ribbed face accepts oil treatment well and is straightforward to maintain with a brush or roller.

Keep the deck free of leaf debris and organic matter between ribs, which can retain moisture and encourage surface mould if left over winter. A stiff brush and warm water is sufficient for routine cleaning — avoid pressure washers on hardwood decking. We stock Remmers and Koopmans hardwood decking oils and stains suitable for tropical hardwoods.

Smooth or Dual Ribbed — Which Should I Choose?

Both boards are the same 25x145mm Yellow Balau hardwood with identical durability, lifespan, and fixing method. The choice comes down to surface finish and intended use:

The smooth board gives a flat, refined deck surface — well suited to contemporary garden designs, raised terraces, and projects where a minimal, architectural appearance is the priority.

This dual ribbed board provides improved grip and anti-slip performance on both faces — the better choice for poolside decking, steps, coastal and waterfront locations, and any exposed deck that will regularly be wet or where slip resistance is a practical requirement.

Frequently Asked Questions