Blackbutt Stub Riser

25x25mm Timber Stub Riser / Legalizer

Complete your staircase with our precision-machined 25x25mm solid timber stub riser, expertly crafted to enhance safety and compliance in open-style stairs.

Dimensions & Profile:

• Dimensions: 25mm x 25mm (square profile for sturdy, compact fitting)
• Edges: Clean, square-cut for a flush installation and professional finish

This stub riser, also known as a legalizer, is designed for attachment to the underside of our 40mm open treads for steel mono and open housed stair systems. It closes the gap between treads, reducing the maximum allowable opening (up to 125mm per Australian standards) to prevent hazards passing through, ensuring child-safe and code-compliant stairs.

Perfect for both new builds and renovations, the 25x25mm construction provides reliable gap reduction and a subtle, integrated look that complements contemporary, coastal, or traditional designs.

These are installed by gluing and nailing them on to the underside of the tread. We recommend sitting them 20mm back from the front of the tread and 20mm away from the stringers on open housed stairs.

Key Benefits:

• Easy underside attachment to minimize gaps and improve safety
• Smooth, sanded surfaces ready for your choice of stain, oil, or clear finish
• Naturally beautiful grain and tones that add warmth and character

Available in both 1m and 1.5m lengths to suit your project. All products are delivered raw, pre-finished sanded to 100 grit.

Blackbutt, a premium Australian native hardwood (Eucalyptus pilularis), boasts a clean, uniform appearance with pale golden-brown to straw tones and a straight, even grain—occasionally accented by subtle gum veins for added rustic charm. Exceptionally durable and fire-resistant, with high density and strength, Blackbutt excels in high-traffic areas and is ideal for stair components that demand longevity and low maintenance. Its neutral palette complements contemporary and coastal  interiors, while its natural toughness makes it suitable for treads, stringers, risers, and handrails that stand up to everyday family use.