Fibre Reinforced Facade Encyclopedia: Testing and standards
Rise in storeys is the National Construction Code’s count of the storeys of a building, calculated under a specific rule that excludes certain storeys, and read with the building class to determine the type of construction. It is not the number of floors, not the number of levels shown on the lift button panel, and not the effective height; each of those is a different measure and they routinely disagree with one another on the same building.
A building with a basement carpark, a ground floor, five levels of apartments and a rooftop plant room has eight floor plates, but a rise in storeys of six. The basement and the plant storey drop out, and the difference is enough to move the building between construction types.
At a glance
| Property | Typical value | Note |
|---|---|---|
| Code reference | NCC 2022 Volume One Part C2, calculation of rise in storeys | Check the edition adopted in your jurisdiction |
| What it feeds | Type of construction, with the building class | Table of type of construction required |
| Measured at | The greatest number of storeys at any part of the external walls | Assessed at any cross section through the building |
| Basement exclusion | A storey partly below finished ground level with its ceiling not more than 1 m above that level | Not counted |
| Rooftop plant exclusion | A top storey containing only plant, lift equipment, water tanks or similar service units | Not counted |
| Roof space | Storeys within the roof space above the counted storeys | Counted |
| Sloping sites | Counted at the point giving the greatest number | A fall across the site can add a storey |
| Not the same as | Effective height, number of floors, number of levels | Effective height is a distance in metres |
How the count is made
The rise in storeys is the sum of the greatest number of storeys at any part of the external walls of the building, plus any storeys within the roof space above those storeys. The phrase at any part of the external walls is doing the work: the assessment is made at whichever cross section produces the highest count, not at the front elevation and not on average.
From that count, two categories of storey are excluded. The first is a storey situated partly below the finished ground level where the underside of its ceiling is not more than one metre above that finished ground level, which is the Code’s way of describing a basement without using the word. The second is a storey at the top of the building that contains only heating, ventilating, lift or other equipment, water tanks or similar service units. A rooftop plant enclosure does not push a building into a more onerous construction type, but a rooftop storey that also contains a residents lounge or a plant room plus any occupiable space is no longer only plant, and it counts.
The Code’s definition of storey itself removes some spaces from consideration before the count even begins. A space containing only a lift shaft, a stairway, a meter room, a sanitary compartment or accommodation for a hot water service is not a storey.
Why sloping sites are the usual trap
On a site that falls, the same floor plate can be a basement at the high end and a fully exposed ground floor at the low end. Because the count is taken at the cross section giving the greatest number of storeys, the low end governs. A lower ground floor that the design team has been calling a basement for six months frequently turns out to be a counted storey, and the building moves from Type B to Type A construction with everything that follows: higher fire resistance levels, non-combustible external walls, and a different cladding strategy.
Rise in storeys, effective height and number of floors
Effective height is the vertical distance in metres between the floor of the lowest storey providing direct egress to a road or open space and the floor of the topmost storey, excluding a topmost storey containing only plant. It is a distance, not a count, and it drives different provisions: sprinkler protection, fire control centres, lift requirements and smoke hazard management thresholds, notably at 25 m.
Number of floors is not an NCC term at all. It is what the client and the marketing material use. A specifier reading a brief that says a six storey residential building should confirm whether that means six floor plates, a rise in storeys of six, or an effective height that happens to suit a six storey building, because the answer changes which fire provisions apply.
The two NCC measures can move independently. Excluding the basement reduces the rise in storeys but not necessarily the effective height, because the lowest storey providing direct egress may still be the basement on a falling site.
What the number decides
Read with the building class, the rise in storeys produces the type of construction from the NCC table: for Class 2, 3 and 9 buildings, a rise of three or more gives Type A; a rise of two gives Type B; a rise of one gives Type C. For Class 5, 6, 7 and 8 buildings the thresholds are one storey higher: four or more gives Type A, three gives Type B, one or two gives Type C. A rise of four or more is Type A for every class covered by Volume One.
Type A and Type B construction carry the NCC requirement that external walls and their attachments be non-combustible, which is where the rise in storeys reaches the facade. A building that lands on Type C can use a combustible cladding within the Deemed-to-Satisfy provisions; a building that lands on Type A cannot, and needs either a non-combustible material such as GRC or a performance solution supported by full-scale testing to AS 5113.
Standards and references
- NCC 2022 Volume One Part C2 Fire resistance, calculation of rise in storeys and type of construction required (check the edition adopted in your jurisdiction)
- NCC 2022 Volume One Schedule 1 definitions of storey, rise in storeys and effective height
- NCC 2022 Volume One Part A6 Building classification
- NCC 2022 Volume One Specification 5 Fire-resisting construction
- AS 5113 Classification of external walls of buildings based on reaction to fire performance
Related terms
Questions specifiers ask
Is rise in storeys the same as the number of floors?
No. It is a defined NCC count that excludes basements meeting the one metre rule and a top storey containing only plant or service equipment, and it is taken at the cross section giving the greatest number.
Does a basement count?
Not where the storey is partly below the finished ground level and the underside of its ceiling is not more than one metre above that level. On a sloping site the same storey may be counted at the low end.
Does a rooftop plant room count?
No, provided it contains only heating, ventilating, lift or other equipment, water tanks or similar service units. Add any occupiable space and it becomes a counted storey.
What is the difference between rise in storeys and effective height?
Rise in storeys is a count that sets the type of construction. Effective height is a distance in metres from the lowest storey providing direct egress to the floor of the topmost storey, and it triggers sprinkler, lift and smoke management provisions.
At what rise in storeys must external walls be non-combustible?
When the building is Type A or Type B construction. For Class 2, 3 and 9 buildings that is a rise of two or more; for Class 5, 6, 7 and 8 buildings it is a rise of three or more.
Once the construction type is settled, ShapeShift can confirm which ShapeShell system carries the tested evidence your facade needs. See ShapeShell fire test data
Reviewed by Richard Halvorsen, General Manager, ShapeShift Technologies. Last updated September 2026.