# Acclimatising oak flooring

> How to acclimatise oak flooring in Australia and NZ: equilibrium moisture content (EMC), ATFA figures, the ±2% rule, climate examples and a step-by-step method.

- URL: https://timbo.com.au/guides/acclimatising-oak-flooring
- 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

- Acclimatisation means bringing timber flooring close to the moisture content it will reach in service before it is laid.
- ATFA gives an equilibrium moisture content (EMC) of about 11% at 25°C and 60% relative humidity, rising to about 16% at 80% RH.
- Australian interiors typically sit at about 8–14% EMC, depending on climate, season and heating or cooling.
- Install timber within about ±2% of its expected in-service EMC.
- Acclimatisation is a moisture target, not a fixed number of days – measure the boards and the site.

## What is acclimatisation?

**Acclimatisation is the process of bringing timber flooring to – or close to – the moisture content it will settle at in the finished building, before it is installed.** The target is the in-service **equilibrium moisture content (EMC)**: the moisture level at which timber stops gaining or losing water to the surrounding air.

Get it right and the floor stays tight and flat. Get it wrong and boards shrink (gaps) or swell (cupping, peaking or lifting) after installation – problems that are hard to fix once parquet is glued and finished.

## The ±2% rule

**Install timber flooring within about ±2% of the EMC it will reach in service** ([WoodSolutions](https://www.woodsolutions.com.au/timber-wiki/moisture-guide)). For example, if a home is expected to sit at around 10% EMC, boards between roughly 8% and 12% are within the target; outside that, the risk of movement problems climbs.

That makes acclimatisation a **moisture target, not a number of days**. Some timber arrives close to the target and needs little time; other timber needs longer, especially when the site and the supply chain have very different conditions.

## EMC: what the numbers say

**Timber's EMC rises as relative humidity rises – ATFA gives about 11% EMC at 25°C and 60% RH, and about 16% at 80% RH.** Typical Australian interiors sit between about 8% and 14%.

| Condition | EMC (approx.) | Source |
| --- | --- | --- |
| 25°C, 60% relative humidity | ~11% | [ATFA](https://www.floorchoices.com.au/information-sheets/acclimatisation-of-timber-flooring/) |
| 80% relative humidity | ~16% | [ATFA](https://www.floorchoices.com.au/information-sheets/acclimatisation-of-timber-flooring/) |
| Typical Australian interiors | ~8–14% | [WoodSolutions](https://www.woodsolutions.com.au/timber-wiki/moisture-guide) |
| Australian-made boards at supply (average) | ~10–12% MC | [ATFA specification](https://www.atfa.com.au/wp-content/uploads/2023/01/ATFA-Specification-for-Solid-Timber-Flooring-FINAL-Oct-18-.pdf) |

For local EMC targets, NATSPEC's technical note on moisture content in timber floors is a useful reference for specifiers ([NATSPEC DES 002](https://www.natspec.com.au/images/TECHnotes/NTN-DES-002-Moisture-content-in-timber-floors.pdf)).

## Climate examples

**Humid, coastal and tropical climates push the in-service EMC toward the upper end of the range; dry inland climates and heavily heated or air-conditioned homes push it toward the lower end.** The table shows the direction of travel – your installer's measurements set the actual target.

| Situation | Likely in-service EMC | What it means for acclimatisation |
| --- | --- | --- |
| Humid coastal or subtropical (e.g. Brisbane, Gold Coast, Auckland) | Toward the upper end of the range | Drier boards may take up moisture – check before laying |
| Temperate (e.g. Melbourne, Adelaide, Wellington) | Mid-range, with seasonal swing | Install for the average, not a dry spell or a wet week |
| Dry inland or alpine (e.g. Canberra in winter, Queenstown) | Toward the lower end, especially with heating | Wetter boards may shrink – allow time and measure |
| Air-conditioned apartment | Lower than outdoor air suggests | Run the HVAC as normal during acclimatisation |
| New build with wet trades or a damp slab | Temporarily high | Don't acclimatise until the building has dried |

Seasonal swings matter too: a floor laid at the end of a humid summer will see drier air in winter, and vice versa.

## How to acclimatise oak flooring: step by step

**Prepare the site first, then measure the timber and the site, and lay only when they're within about ±2%.**

1. **Finish wet trades.** Plastering, painting, tiling and screeding add moisture. Wait until they're done and dry.
2. **Close in and condition the building.** Windows and doors in, and heating or cooling running as it will in normal use.
3. **Test the subfloor.** Slab moisture has its own limits, set by the adhesive maker – see [installing parquet over a concrete slab](https://timbo.com.au/guides/installing-parquet-over-concrete-slab).
4. **Deliver and store correctly.** Store boxes flat, off the slab, away from external doors and direct sun, in the rooms where they'll be laid.
5. **Follow the supplier's instructions on opening packs.** Some products should stay sealed until laying; others are opened and spread out. Ask Timbo for the instructions for your batch.
6. **Measure board moisture content** on a sample of boards from several boxes with a meter set for oak – see [moisture content in timber flooring](https://timbo.com.au/guides/moisture-content-timber-flooring).
7. **Measure or estimate the in-service EMC** from indoor temperature and humidity readings over several days.
8. **Lay when within about ±2%.** Record readings and dates in the job file.

**Talk to the Timbo team:** Questions about specifications, stock or partnering? We reply during business hours, Monday to Friday. → https://timbo.com.au/pages/contact-us

## Storage on site

**How parquet is stored on site matters as much as how long it's there.**

| Do | Don't |
| --- | --- |
| Store boxes flat on bearers, off the slab | Stack directly on a new slab |
| Keep them in the rooms where they'll be laid | Leave them in a garage, shipping container or outdoors |
| Keep away from external doors, windows and direct sun | Store next to heaters or air-conditioning outlets |
| Keep wrapping intact until the instructions say to open | Open boxes while plastering or painting is under way |
| Protect from other trades' traffic and spills | Use boxes as a workbench |

When delivery is booked, make sure the site is ready to receive the timber – see [delivery and lead times](https://timbo.com.au/partners/delivery-and-lead-times) for how Timbo handles freight.

## Acclimatisation checklist for installers

- Site enclosed, wet trades finished, HVAC running as normal
- Slab tested and within the adhesive maker's limit – in NZ, see the [NZ slab guide](https://timbo.com.au/guides/timber-flooring-over-slab-nz)
- Board moisture readings recorded from several boxes
- Indoor temperature and humidity recorded over several days
- Boards within about ±2% of the expected in-service EMC
- Batch number recorded and boxes blended during laying

## Acclimatising solid oak parquet

**Solid oak parquet blocks are short, so each block moves less in absolute terms than a long board – but there are hundreds of joints per room, and a whole glued floor still moves as a unit.** That's why moisture control and correct [expansion allowances](https://timbo.com.au/guides/expansion-gaps-solid-parquet) matter just as much for parquet as for boards.

Timbo does not publish a dispatch moisture content figure on this website. Measure the blocks on arrival and compare with site conditions; your Timbo partner or Timbo can advise on the batch.

## Underfloor heating and acclimatisation

**With underfloor heating, the heating system is commissioned and run before installation so the slab is dry and the timber acclimatises to heated conditions.** Follow the heating system's and adhesive maker's protocol. See [underfloor heating and oak flooring](https://timbo.com.au/guides/underfloor-heating-oak-flooring).

## Sources

- [ATFA (floorchoices.com.au) – Acclimatisation of timber flooring](https://www.floorchoices.com.au/information-sheets/acclimatisation-of-timber-flooring/)
- [WoodSolutions – Moisture guide](https://www.woodsolutions.com.au/timber-wiki/moisture-guide)
- [ATFA – Specification for solid timber flooring](https://www.atfa.com.au/wp-content/uploads/2023/01/ATFA-Specification-for-Solid-Timber-Flooring-FINAL-Oct-18-.pdf)
- [NATSPEC TECHnote DES 002 – Moisture content in timber floors](https://www.natspec.com.au/images/TECHnotes/NTN-DES-002-Moisture-content-in-timber-floors.pdf)

## Frequently asked questions

### How many days should oak flooring acclimatise before installation?

There is no universal number of days. Acclimatisation is complete when the boards are within about ±2% of the moisture content they'll reach in service. Some timber arrives already close and needs little time; some needs longer. Measure, and follow the manufacturer's and adhesive maker's instructions.

### Should I open the boxes to acclimatise parquet?

Only when the site is ready. Opening boxes in a building with wet plaster, a damp slab or no climate control lets the timber pick up moisture it will later lose. Follow the supplier's instructions – some products are meant to stay sealed until laying.

### What is equilibrium moisture content?

Equilibrium moisture content (EMC) is the moisture content timber settles at when it has stopped gaining or losing moisture to the surrounding air. It depends mainly on relative humidity and, to a lesser extent, temperature.

### Does air-conditioning affect acclimatisation?

Yes. Air-conditioning and heating lower indoor humidity, so timber in a conditioned home usually settles at a lower EMC than outdoor air would suggest. Acclimatise with the home running as it will be lived in.

### What happens if oak flooring isn't acclimatised?

Boards laid too wet shrink as they dry, opening gaps between blocks. Boards laid too dry take up moisture and swell, which can cause cupping, peaking or lifting. Both problems are much harder to fix after the floor is glued and finished.

## Related pages

- [Moisture content in timber flooring](https://timbo.com.au/guides/moisture-content-timber-flooring) – Moisture content in timber flooring explained: MC vs EMC, the 8–14% Australian interior range, the ±2% rule, and how to measure oak and slab moisture.
- [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.
- [Expansion gaps for solid parquet](https://timbo.com.au/guides/expansion-gaps-solid-parquet) – Expansion gaps for solid oak parquet: why glued floors still need them, where to leave them, what sets their size and the signs a floor is too tight.