Hi @wayneo,
Thank you for your question about building a ramp off your deck.
Ramp building follows much the same principles as building a deck in that you need posts, bearers, joists and a decking material; the main difference is that you are doing it on a gradient. The tricky thing about ramps is designing them, so they comply with the relevant Australian and New Zealand Standards and the National Construction Code, and for this reason, I'd suggest you seriously consider having a suitably licenced carpenter or builder assist with this work to ensure everything is built to code. The construction itself isn't hugely difficult; it's the compliance side that is tricky, and ensuring you are in line with the relevant codes is important for the safety of yourself and any other users of the ramp.
I'd suggest you start by having a read through Part 11.2 Stairway and ramp construction | NCC, as it will dictate much of the design considerations you would need for your ramp.
One of the main things to note is that the NCC requires a ramp to be no more than a 1:8 gradient, meaning for every metre of vertical change, the ramp must run eight metres horizontally. To build a ramp to achieve this, it would need to be a minimum of 11.2 metres long.
To achieve this length, a landing and change of direction is pretty much essential. The rules for landings can be seen in the NCC Part 11.2.5.
It is also a requirement that the ramp has a suitable slip rating for the gradient. For a ramp, this means the sloped section needs a P5 slip rating and the landings need a P4 slip rating. This can be achieved using a coating such as this Dy-Mark 1L Clear TreadRite.
The other thing to consider is the requirement for a balustrade, barrier or handrail. The rules for this can be in the NCC Part 11.3 Barriers and handrails | NCC.
I'd be happy to interpret and advise further if you have further questions.
Jacob
