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Post Date:
2025.10.27
When designing or renovating a solid wood staircase, many homeowners naturally focus on visible details such as the choice of wood species, finishes, or handrail designs. Yet one technical factor that often goes unnoticed plays a critical role in both performance and appearance: stair tread thickness, also known as the thickness of the stepboard. Whether you choose 26mm, 30mm, 35mm, or 42mm, the thickness of your wood stair treads directly affects durability, stability, and the overall look and feel of your staircase.
This article will guide you through the differences between common stepboard sizes, why they matter, and how to select the right option for your home—whether you’re building a traditional staircase on concrete or a sleek modern floating staircase on steel.
What Is a Stepboard?
The stepboard, or stair tread, is the flat horizontal surface that you step on as you move up and down the staircase. It bears the greatest load of the structure, supporting body weight day after day. In a solid wood staircase, the stepboard is more than a functional surface—it is also an expression of craftsmanship. Each plank displays the natural beauty of the timber grain, adding warmth, elegance, and a sense of permanence to the home.
Because of this dual role, both practical and aesthetic, stair tread thickness cannot be ignored. A stepboard that is too thin may lack the strength to last for long, while one that is overly thick may drive up costs or overwhelm the balance of your staircase design.
The Slim and Cost-Friendly 26mm Stepboard
At the entry level, many homeowners consider the 25–26mm stepboard, which is roughly one inch thick. This option is slim, budget-conscious, and suitable for homes where cost efficiency and space savings are priorities. When made from dimensionally stable heavy hardwoods such as Merbau, even a 26mm Merbau stepboard can withstand daily household use with ease.
However, thinner stair treads do come with trade-offs. They may not feel as substantial underfoot as thicker boards. If produced from a less stable wood species, a 26mm board may also be more vulnerable to warping or long-term movement. For these reasons, this thickness is often chosen for secondary staircases or homes where affordability is more important than grandeur.
3The Practical 30–35mm Stepboard – Ideal for Concrete Slabs
For staircases built on a concrete slab base, the most common choice falls between 30mm and 35mm. This range has become the sweet spot for modern residential staircases. Because the concrete provides solid structural support beneath the treads, the wood does not need to carry the entire load on its own.
A 30mm Merbau staircase or a 35mm teak staircase offers a reassuringly solid feel underfoot while showcasing the richness of natural hardwood grain. At this thickness, the boards are also robust enough to be sanded and refinished multiple times throughout their lifespan, allowing the staircase to look fresh for decades. The balance of strength, elegance, and cost-effectiveness makes 30–35mm the preferred size for most solid wood staircases on concrete structures.
The Premium 40–45mm Stepboard – Best for Steel Plate or Floating Staircases
When the staircase is constructed on a steel plate structure or designed as a floating staircase, the stepboard must handle more stress on its own. In these cases, a thickness of 40mm to 45mm is strongly recommended. Unlike concrete, steel does not distribute weight evenly, which means the wood tread must absorb greater impact and resist flexing or vibration.
Thicker hardwood stepboards in the 40–45mm range provide exceptional stability. Walking on them feels secure and substantial, reducing any sense of bounce. Visually, the extra thickness creates a striking impression: bold treads that immediately convey luxury and permanence. In modern architectural homes, floating staircases with 42mm Teak or Merbau stepboards often become the centerpiece of the interior.
For cantilevered staircases or steel-frame designs, this thickness is not just a preference—it is a structural necessity to ensure safety and durability.
5Balancing Aesthetics, Structure, and Budget
So, should you choose 26mm, 30–35mm, or 40mm and beyond? The answer lies in balancing your aesthetic goals, staircase structure, and budget. For homeowners seeking a cost-effective solution, 26mm boards in stable hardwoods may be enough.
For most concrete slab staircases, 30–35mm offers the best combination of strength, style, and practicality. For architectural steel or floating staircases, 40–45mm delivers the stability and grandeur required.
The Role of Wood Species and Installation
Stepboard thickness alone does not determine performance—the choice of wood is equally important. Dense tropical hardwoods such as Teak and Merbau offer excellent strength even at slimmer sizes, while species like White Oak or Walnut are often chosen for their timeless aesthetics, whether in light, modern tones or rich, cozy shades. Pairing the right species with the right thickness ensures both durability and beauty.
Of course, even the best material can fail without proper installation. A carefully installed 30mm stepboard on concrete may outlast a poorly fitted 42mm stepboard on steel. The supporting structure must be designed to carry the load, and the wood should always be properly acclimatized to its environment to minimize the risk of warping or movement.
Conclusion – Choosing the Right Stepboard
Stepboard thickness is more than a technical detail—it shapes how your staircase looks, feels, and performs for generations. From the slim practicality of 26mm, to the balanced reliability of 30–35mm on concrete, to the bold presence of 42mm on steel or floating staircases, each size has its place.
By considering your staircase structure—concrete or steel—and pairing it with the right hardwood species, you can create a solid wood staircase that is safe, durable, and timeless.
At Hengwood, we craft stepboards in a variety of sizes and wood species, ensuring that whether you seek elegance, strength, or architectural grandeur, your staircase will always reflect the character of your home.
It is solid. It is warm. It is love. It is Hengwood.
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