Stairs

Guide to Internal Stair Requirements
What every builder, installer and homeowner should know before working with stairs

When it comes to timber flooring, stairs can be one of the trickiest parts of the job. They’re not just another surface to cover – they’re a safety feature governed by strict building rules. The National Construction Code (NCC) outlines stair dimensions, slope requirements, and safety measures that must be met, while additional standards address slip resistance to help prevent accidents.

But here’s the catch:

• Even small changes in floor coverings can throw stair measurements out of tolerance.
• Requirements differ depending on whether the stairs serve habitable or non-habitable rooms.
• Since 2014, slip resistance standards apply to domestic stairs – and not all finishes on the market comply.

Many contractors and homeowners are surprised to learn that something as simple as replacing carpet with a timber overlay can cause compliance issues. If that happens, who’s responsible — the builder or the flooring contractor? The answer isn’t always straightforward.

That’s why this guide was created. Inside, you’ll find:

• The core NCC requirements for internal stairs
• Key terminology explained with supporting diagrams
• The tolerances allowed for riser and going dimensions
• What the slip resistance rules really mean in practice
• Practical tips to avoid disputes or non-compliance