Composite Decking Bullnose Edge Installation: Step-by-Step Guide
A bullnose edge board is the finishing detail that transforms a good decking installation into a great one. Designed with a rounded front edge, the bullnose profile creates a smooth, safe and attractive transition at decking perimeters, step edges and raised platforms.
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Thu, 28 Jul 2026
This decking bullnose edge installation guide covers how to install bullnose boards for a neat, durable finish.
What Is a Bullnose Edge Board?
A bullnose decking board features a gently curved front edge, used to cap off exposed edges of a deck.
It’s commonly installed:
Along the outer edge of raised decking areas.
On steps and stairs.
Bullnose boards provide a smooth, rounded edge that protects edges and creates a visually continuous border for modern deck designs. Composite bullnose boards are particularly popular for their consistent colour, low maintenance and fade resistance.
How to Install Composite Decking Bullnose Edging
This guide is for use with EnviroBuild Frontier composite decking.
Bullnose boards are solid boards with a rounded edge. This can frame a decking area or work as a finishing touch needing a rounded edge board. The bullnose board has increased strength due to the solid internal structure and can be used as a step.
Ensure to keep a 6mm expansion gap between edge board butt joints.
The bullnose must be installed before laying down the decking.
There are two methods for installing bullnose boards:
Parallel to the decking
Perpendicular to the decking
Parallel bullnose board decking installation
Step 1
Where fixing the bullnose boards around a corner, mitre the ends at 45° angles.
Step 2
Secure starter fasteners onto the outer joist at 400mm intervals.
Step 3
Line up the bullnose board and lay the underside groove directly on top of the starter fasteners.
Step 4
Push the board forward to lock the board.
Step 5
Secure the remaining side of the bullnose board with hidden fasteners.
Perpendicular bullnose board decking installation
Step 1
A full joist width must be used under each deck board end, thus where the bullnose board runs perpendicular to the main deck, you must have a double joist structure.
Step 2
Secure starter fasteners onto the outer joist at 400mm intervals.
Step 3
With the bullnose board in place, screw through the hidden fastener groove at a 45º angle, securing it to the joist.
Pre-drill pilot holes in the deck boards 2mm wider than the screw shank.
Do not over drive screws into the deck boards to avoid the material splitting.
Common Mistakes to Avoid
Over-tightening screws, causing stress on boards.
Insufficient support under overhanging edges.
Forgetting expansion gaps between boards.
Avoiding these issues ensures your bullnose edges remain durable, safe and beautifully finished.
A Safe, Stylish and Long-Lasting Deck Finish
Installing a bullnose edge board is a simple yet transformative detail that elevates your decking project. With precise measurement, clean cutting and proper fixing, you’ll achieve a visually cohesive edge that enhances both the performance and design of your outdoor space.
Whether used for steps, borders or raised platforms, composite bullnose edges offer a premium architectural finish built to last for decades.
EnviroBuild offers a full range of composite decking boards, bullnose trims, and fascia accessories, engineered for fast installation and lasting performance.
