When building in New Zealand, most floating stair designs will fall under either a main private stairway or secondary private stairway.
A main private stairway consists of a private stairway with the sole purpose of providing access to and from frequently used spaces such as living areas, kitchens and garages. All exterior private stairways are also categorised under this section.
A secondary private stairway is a private staircase that isn’t used as frequently as a main staircase. These secondary stairwells provide access to another floor containing only bedrooms, bathrooms, or similar accommodation.
Today we’ll be going over the regulations that are associated with floating staircases across New Zealand, providing the important figures that need to be abided by to create a safe floating staircase.
D1 Access routes
The objective of the D1 Access routes clause of the New Zealand Building Code is to safeguard people from injury during movement into, within and out of buildings.
The tread guidelines within the D1 Access routes states that there should be no larger gap than 100mm between treads. This guideline standard can be achieved by either a solid 80-90mm thick tread or an L shape tread. The nosing or overhang of tread must be between 15mm and 25mm.
Following the building code stated in D1, open risers shouldn’t be used for accessible stairways in commercial buildings. But they are allowed in residential properties for private stairways (both main and secondary stairways) if specific criteria are met.
For main private stairways the tread must be at least 280mm deep and the risers must be no more than 190mm high. While secondary private stairway will require the tread to be at least 250mm deep and the riser must be no more than 200mm high.
Whilst this is the outlined requirements to follow New Zealand D1 Access routes regulation, at Ackworth House we recommend a tread depth of 290-300mm and a riser height of 175-185mm. This way you can create a comfortable and airy staircase that’s easy to walk up and down and doesn’t look too small in your selected space.
The B1 clause of the building code looks at the structure of all building components. Because floating stairs are a structural part of your building it means they must comply with the outline codes in B1 building guide. This means that a certain level of care needs to be followed in both the designing and engineering of your staircase to ensure that its load bearing and fixing details are up to standard, this can be achieved through the use of a certified structural engineer.
The structural engineer will be able to provide a signed Producer Statement for Design (PS1) which will need to be submitted to your local council with the building’s consent form. A PS1 is crucial to the progression of your build, giving evidence that the design complies with the building code stated in B1.
Ackworth House has a range of floating stair designs that have been designed and engineered to comply with Building Code Clause B1 Structure. This means we can provide you with a site specific PS1 very quickly and easily.
But it doesn’t stop there, we also manufacture and install all components of floating stairs for you too. Contact the team at Ackworth House to start your staircase journey today!