# Timber flooring in bushfire-prone areas (AS 3959)

> Does AS 3959 restrict timber floorboards in bushfire-prone areas? What BAL rules cover, why internal floors over a slab are usually unaffected, what to check.

- URL: https://timbo.com.au/guides/timber-flooring-bushfire-areas
- Publisher: Timbo (https://timbo.com.au) – trade supplier of European oak floorboards to partners in Australia and New Zealand
- Last updated: 2026-10-14
- Contact (email only): partnerships@timbo.com.au

## Key facts

- AS 3959 is the Australian Standard for construction of buildings in bushfire-prone areas, referenced by the NCC.
- Requirements scale with the site's Bushfire Attack Level (BAL), from BAL-LOW to BAL-FZ.
- The standard targets elements exposed to embers and radiant heat, such as elevated subfloors and decks, not internal floors over a slab.
- Internal oak flooring on a concrete slab is generally unaffected, but the certifier has the final say.
- Suspended timber floors on open subfloors need more care at higher BALs.

## Short answer

**For most projects, AS 3959 does not stop you installing an internal oak floor.** The standard sets construction requirements for buildings in designated bushfire-prone areas, and it focuses on the parts of a house exposed to embers, radiant heat and flame – walls, roofs, windows, vents, decks and **elevated subfloors**. An internal floor of [solid European oak floorboards](https://timbo.com.au/floorboards/european-oak-floorboards) or parquet glued to a concrete slab sits inside the building envelope and is generally outside its scope ([WoodSolutions](https://www.woodsolutions.com.au/system/files/Designinginbushfireareas.pdf)).

The exception is **suspended timber floors over an open subfloor**, where the underside of the floor may be exposed. That's where the designer and certifier need to check the detail.

## What AS 3959 covers

**AS 3959 – Construction of buildings in bushfire-prone areas – is referenced by the National Construction Code (NCC) for houses and certain other residential buildings in designated bushfire-prone areas.** It sets deemed-to-satisfy construction requirements that become stricter as the site's Bushfire Attack Level rises ([WoodSolutions](https://www.woodsolutions.com.au/system/files/Designinginbushfireareas.pdf)).

| Bushfire Attack Level | Main exposure | What it generally means for flooring |
| --- | --- | --- |
| BAL-LOW | Very low risk | No specific construction requirements |
| BAL-12.5 | Ember attack | Attention to gaps and exposed subfloor details |
| BAL-19 | Ember attack and increasing radiant heat | Subfloor and deck details tighten |
| BAL-29 | Higher radiant heat | Stricter requirements for exposed timber elements |
| BAL-40 | High radiant heat, possible flame contact | Many exposed timber elements restricted |
| BAL-FZ | Flame zone | Most stringent; specialist design |

This table is a general orientation only. The actual requirements are in the current edition of AS 3959 and any state variations, and your certifier applies them. Some states add their own planning rules – for example, NSW projects also follow *Planning for Bushfire Protection*.

## Internal floors over a concrete slab

**An internal oak floor on a slab-on-ground is generally unaffected by AS 3959, because there is no exposed subfloor and the flooring is not part of the building's external envelope.** This is the most common situation for Timbo's 18mm solid oak herringbone and chevron parquet, which is usually glued directly to a flat, dry slab.

For these jobs the usual technical issues still apply – slab moisture, flatness, adhesive and acclimatisation. See [installing parquet over a concrete slab](https://timbo.com.au/guides/installing-parquet-over-concrete-slab) and [adhesives and moisture barriers](https://timbo.com.au/guides/adhesives-and-moisture-barriers).

## Suspended timber floors and elevated subfloors

**Where the floor is raised on stumps, piers or a framed subfloor, AS 3959 may set requirements for the subfloor supports, framing and the flooring itself, depending on the BAL and whether the subfloor is enclosed.** Enclosing the subfloor with compliant materials is a common way designers manage this.

| Floor type | Typical AS 3959 relevance | Who to ask |
| --- | --- | --- |
| Parquet glued to slab-on-ground | Generally not affected | Certifier to confirm |
| Floorboards on joists, enclosed subfloor | Usually managed by the enclosure | Designer / certifier |
| Floorboards on joists, open subfloor | Can be affected at higher BALs | Designer / certifier |
| Timber deck or external landing | Directly regulated | Designer / certifier |
| Upper-storey internal floor | Generally not affected | Certifier to confirm |

If you're a builder working on a raised-floor home in a bushfire-prone area, raise the flooring question early. See our page for [builders](https://timbo.com.au/partners/builders).

## Commercial buildings are a separate question

**Commercial and multi-residential projects have separate NCC fire hazard requirements for floor linings, which are unrelated to bushfire rules.** European oak parquet supplied with a Declaration of Performance under EN 14342 typically reports a reaction-to-fire class; untreated solid parquet is typically D_fl-s1 ([dataholz](https://www.dataholz.eu/en/building-materials/wood-flooring-and-parquet.htm)). Whether that evidence satisfies the NCC requirement for the building class is a question for the certifier or fire engineer. See [commercial oak flooring](https://timbo.com.au/floorboards/commercial-oak-flooring).

## Checklist for flooring businesses

**Before quoting oak flooring in a bushfire-prone area, confirm the BAL, the floor construction and the certifier's position in writing.**

1. Ask the builder or owner whether the site is in a designated bushfire-prone area and what BAL applies.
2. Confirm the floor type – slab, enclosed subfloor or open subfloor.
3. For internal floors over a slab, note on the quote that AS 3959 requirements were confirmed as not applicable by the certifier (or attach their advice).
4. For raised floors, follow the designer's subfloor detail – don't change materials or enclosures without approval.
5. Keep product information on file. Ask Timbo for the documentation available for your order.

Architects and designers can add these points to the flooring section of a specification – see our [specification guide](https://timbo.com.au/guides/specifying-oak-flooring-architects).

## Why this matters for selling oak

**Clients in bushfire-prone areas sometimes assume timber floors are not allowed, and lose interest in a product that is perfectly suitable.** A clear, accurate answer – internal floors over slab are generally unaffected, confirm with the certifier – keeps the sale on track without overstating anything. For the wider product decision, see the [floorboards buying guide](https://timbo.com.au/guides/floorboards-buying-guide-australia).

## Talking to homeowners about it

**Keep the message simple: the bushfire rules are about the outside of the house, and the certifier confirms the details.** Homeowners rebuilding or renovating in bushfire-prone areas often have a long list of approvals to manage, and flooring is rarely the hard part. Useful points to make:

- The BAL for the site is already set in the approval documents – the flooring business doesn't decide it.
- Oak glued to a slab, or laid over an enclosed subfloor built to the approved design, is the common, straightforward case.
- Anything unusual – an open subfloor, a timber floor continuing out to a deck, an exposed landing – goes back to the designer.
- Product choice (species, grade, pattern) is otherwise the same as anywhere else: see [oak flooring grades](https://timbo.com.au/guides/oak-flooring-grades).

Homeowners looking for a supplier and installer can [find a Timbo partner](https://timbo.com.au/partners/find-a-partner).

**Become a Timbo partner:** Wholesale pricing, free samples and marketing support for flooring businesses in Australia and New Zealand. → https://timbo.com.au/pages/be-our-business-partner

## Sources

- WoodSolutions – Designing and building in bushfire-prone areas: [woodsolutions.com.au](https://www.woodsolutions.com.au/system/files/Designinginbushfireareas.pdf)
- dataholz – Wood flooring and parquet (reaction to fire of untreated solid parquet): [dataholz.eu](https://www.dataholz.eu/en/building-materials/wood-flooring-and-parquet.htm)
- Standards Australia – AS 3959 Construction of buildings in bushfire-prone areas: [standards.org.au](https://www.standards.org.au)

## Frequently asked questions

### Can I install oak floorboards in a bushfire-prone area?

Usually yes. AS 3959 regulates exposed elements like elevated subfloors and flooring exposed to radiant heat, not internal floors over a slab ([WoodSolutions](https://www.woodsolutions.com.au/system/files/Designinginbushfireareas.pdf)). Confirm the BAL and requirements with the certifier.

### What is a BAL rating?

BAL (Bushfire Attack Level) measures how severely a building could be exposed to ember attack, radiant heat and flame. The levels are BAL-LOW, BAL-12.5, BAL-19, BAL-29, BAL-40 and BAL-FZ (Flame Zone). The higher the BAL, the stricter the construction requirements.

### Does a herringbone floor glued to a slab need a fire rating for AS 3959?

Generally not. A slab-on-ground floor has no exposed subfloor, and the oak sits inside the building envelope. Commercial buildings have separate NCC fire hazard rules for floor linings – see our commercial page.

### What about a raised timber floor on stumps?

This is where AS 3959 can apply. Depending on the BAL, the subfloor may need to be enclosed or the supports and flooring may need to meet specific requirements. Your designer and certifier set the detail.

### Does AS 3959 apply in New Zealand?

No. AS 3959 is an Australian Standard. New Zealand has its own building code framework, so check with the local building consent authority for NZ projects.

### Who decides the BAL for a site?

A BAL assessment is done for the site as part of the planning or building approval, typically by a qualified bushfire consultant or the relevant authority. The flooring business works from the approved plans.

## Related pages

- [Installing parquet over a concrete slab](https://timbo.com.au/guides/installing-parquet-over-concrete-slab) – How to install solid oak parquet over a concrete slab in Australia: flatness (~3mm/3m), moisture testing, barriers and adhesives, setout, gluing and finishing.
- [Specifying oak flooring – a checklist for architects and designers](https://timbo.com.au/guides/specifying-oak-flooring-architects) – A spec checklist for European oak flooring: species, grade, size, construction, EN 14342 DoP, fire class, slip, acoustics, moisture, substrate and finish.
- [Commercial oak flooring for hospitality, retail and offices](https://timbo.com.au/floorboards/commercial-oak-flooring) – Solid European oak parquet for commercial interiors: hospitality, retail and offices. Finishes, fire reaction class, slip resistance and maintenance planning.