Timber floor coverings: solid hardwood, engineered and bamboo

TL;DR

Solid hardwood, engineered timber and bamboo are the three timber-based floor covering options for Australian residential builds. Solid strip hardwood runs $150 to $250/m2 finished (supply, lay, sand and coat); engineered timber runs $110 to $200/m2 installed; bamboo is broadly similar to engineered. The system choice (nail-down, direct-stick, floating) is driven by substrate: solid 19 mm strip goes nail-down on joists or battens; engineered and bamboo can float, glue or (sometimes) nail. Every system needs a minimum 10 mm perimeter expansion joint with intermediate joints every 6 m across the grain. Concrete substrate must be below 5.5% moisture content before laying. Skip the acclimation step when site EMC differs from expected in-service conditions: acclimate to the finished environment, not the construction site.

What it is

Timber floor coverings are finish floor products manufactured from solid timber, engineered timber (a structural core bonded with a hardwood or bamboo face lamella), or bamboo (technically a grass but installed and graded as timber flooring). All three fit by tongue and groove or click-lock profiles.

Also known as: hardwood floors, strip flooring, parquet (short-length solid pieces), floating floors (when laid unattached to the substrate).

Category: Finish floor covering, second-fix trade.

Properties

Property	Solid hardwood	Engineered timber	Bamboo
Typical board thickness	19 mm (strip)	12 to 21 mm	14 to 20 mm
Typical board width	65 to 130 mm (strip)	90 to 220 mm	90 to 180 mm
Structural core	Full solid timber	HDF, multi-ply, or LVL	Strand-woven or laminated bamboo
Face lamella thickness	N/A (solid)	2 to 6 mm hardwood veneer	Full thickness bamboo
Grading standard	AS 2796 (hardwood)	No national AS; manufacturer grade	ATFA Bamboo Industry Standard
Installed moisture content (supply)	9 to 14% per AS 2796	Manufacturer specified, typically 6 to 12%	Manufacturer specified
Dimensional movement	High (full-section moves with MC change)	Low to moderate (cross-ply reduces width movement by up to 90%)	Moderate (strand-woven is more stable than laminated)
Re-sanding potential	Yes, multiple times	Limited (face lamella thickness determines number of sands)	Varies; thicker face allows one or two sands

Grades and variants

Solid hardwood (AS 2796)

Three grades under AS 2796. Grade differences relate only to the size and frequency of visible features (gum veins, knots, borer, discolouration). Moisture content, tolerances and machining requirements are identical across grades.

Grade	Character
Select	Minimal features; clean appearance
Medium Feature (Standard)	More gum veins, knots and colour variation
High Feature	Prominent character; rustic or colonial look

Common species: blackbutt, spotted gum, merbau, jarrah, tallowwood, Sydney blue gum, alpine ash.

Engineered timber

No single national Australian Standard covers engineered flooring. Products are graded by their manufacturer, typically using the same Select / Medium Feature / High Feature naming aligned to AS 2796 for the face species. Veneer thickness is the critical selection variable: thicker face lamella (4 mm or more) allows re-sanding; thin-face products (2 mm or under) are effectively single-life.

Bamboo

ATFA’s Bamboo Flooring Industry Standard provides the Australian installation reference. Two main constructions: laminated bamboo (strips glued horizontally or vertically) and strand-woven bamboo (fibres compressed under heat and pressure). Strand-woven is significantly harder and more stable. Bamboo is not covered by AS 2796 but is installed using the same floating and glue-down methods as engineered timber.

Where to use

Living areas, bedrooms, hallways, studies
Suspended timber sub-floors (joists and bearers)
Concrete slabs (with correct substrate prep and moisture management)
Over radiant-in-slab heating (engineered and bamboo only; solid strip is not suitable over hydronic slab heating)

Where NOT to use

Wet areas (bathrooms, laundries, en suites): timber swells with sustained moisture, will cup and gap
High-humidity rooms without climate control: the floor will move beyond acceptable tolerances
Ground-contact or below-slab situations
Solid hardwood over in-slab hydronic heating: engineered or bamboo only; solid strip movement at elevated slab temperatures exceeds acceptable limits

Installation methods

The method is chosen based on substrate type, product specification, and acoustic requirements. Mixing methods on the same product without manufacturer approval is a defect risk.

Method	Best for	Substrate
Secret nail (nail-down)	Solid 19 mm strip; some engineered	Timber joists, plywood, battens
Direct-stick (glue-down)	Solid and engineered wide boards; parquet	Flat, dry concrete; plywood
Floating (click or glued T&G)	Engineered; bamboo; laminate	Concrete, particle board, existing floors
Batten system	Solid strip over concrete	Concrete (battens pinned over 200 µm poly membrane)

Nail-down (secret nail)

Standard method for 19 mm solid strip on joists or plywood substrate. Boards are secret-nailed through the tongue at 300 to 450 mm centres using a flooring nailer (cleat nailer or stapler). Boards 85 mm wide or less may be secret-nailed only. Boards 86 to 130 mm wide may be secret-nailed or face-nailed; wider boards require top (face) nailing in addition to secret fixing to manage cupping.

Where solid strip runs over concrete, install 45 x 45 mm battens at 450 mm centres over a 200 µm polyethylene membrane (lapped 200 mm, taped at joints, turned 75 mm up walls). Batten direction runs 90 degrees to the flooring direction (verified 2026-05-10, WoodSolutions, Forest and Wood Products Australia).

Direct-stick (glue-down)

Used for solid and engineered boards directly bonded to concrete or plywood substrate. Requires a polyurethane or MS polymer flooring adhesive; standard construction adhesive is not appropriate. Full bed of adhesive with the correct trowel notch size (follow adhesive manufacturer’s instructions). The slab must be clean, dust-free and structurally sound. A moisture vapour barrier (MVB) coating is applied to the slab before adhesive where slab moisture exceeds the adhesive manufacturer’s limit (verified 2026-05-10, WoodSolutions).

See adhesives-construction for adhesive product selection.

Floating

Boards interlock by click-lock or glued tongue and groove over a foam or foam-foil underlay. No fixings into the substrate. The floor “floats” as one assembly. A 200 µm polyethylene moisture barrier sheet goes under the underlay on concrete slabs (verified 2026-05-10, WoodSolutions). Floating is not suitable for all solid hardwood products; check manufacturer’s installation instructions.

Substrate preparation

Flatness

Concrete subfloors must comply with AS 3600, permitting a maximum deviation of +/- 3 mm over a 3 m radius. Deviations beyond this require grinding, self-levelling compound, or backer packing before flooring goes down. High spots create cupping and squeaking; low spots allow board movement that cracks adhesive bonds in direct-stick installations.

For suspended timber subfloors: sheets and boards must be firm, flat and free of movement. Fix squeaks before laying.

Moisture (concrete slab)

Concrete subfloors must be below 5.5% moisture content (by impedance meter) before any timber flooring is installed without a moisture vapour barrier system. Where moisture exceeds this threshold, use a 200 µm polyethylene membrane (floating and batten) or an applied moisture vapour barrier coating (direct-stick). Moisture in the slab is the single most common cause of timber flooring failure in Australia (verified 2026-05-10, WoodSolutions).

Acclimation

Acclimation is the process of bringing the flooring’s moisture content to match the expected in-service equilibrium. Acclimate to the finished, conditioned environment, not to the construction site. On an active construction site with open windows and no HVAC operating, the site EMC may be significantly higher than the dwelling’s long-term in-service EMC. Laying to site conditions and then switching on the air conditioning can cause the floor to shrink beyond acceptable limits. Store product on-site for the period and conditions recommended by the manufacturer (verified 2026-05-10, ATFA).

Expansion gaps

Movement in timber flooring is the key design constraint. All timber-based products expand and contract with changes in ambient humidity.

Perimeter expansion gap: minimum 10 mm between the edge of the flooring and every fixed structure (walls, door frames, columns, hearths). Larger rooms need larger gaps (verified 2026-05-10, WoodSolutions).
Intermediate expansion joints: provide an expansion joint equivalent to 10 mm for every 6 m of floor width across the grain. In rooms wider than 6 m across the board direction, a break joint in the floor is required (verified 2026-05-10, WoodSolutions).
Doorways: expansion gaps at doorways are covered by a threshold strip or feature timber. Do not allow flooring to lock against the door stop without an adequate gap.
Skirting coverage: the skirting board covers the perimeter gap. See skirting and architrave installation for the sequence. The skirting is fixed to the wall, not the floor.

Tolerances and acceptance

Floor levelness (NSW Guide to Standards and Tolerances 2017): Floor surface within 10 mm of level over the entire room; within 5 mm over any 3 m length, measured within the first 24 months (verified 2026-05-10, NSW Fair Trading Guide to Standards and Tolerances 2017).

Board-to-board lippage: Per current HIA Guide to Materials and Workmanship. Verified numerical tolerance pending HIA member access. [HIA-115]

Board-to-board gap width: Per current HIA Guide to Materials and Workmanship. Normal seasonal movement causes gaps to open and close; gaps that open in dry conditions and close in humid conditions are not defects. A permanent gap that does not close under normal seasonal conditions may be a defect. Verified gap width tolerance pending HIA member access. [HIA-116]

Squeaking floors (NSW and VIC Guides): Isolated squeaks in 10% or fewer of boards are typically within tolerance for the first 24 months; widespread or persistent squeaking is a workmanship defect. Causes include inadequate secret nailing, nailing through the substrate into voids, or boards not making full contact with the substrate (verified 2026-05-10, NSW Guide to Standards and Tolerances 2017).

Cupping and crowning: Cupping (edges higher than the board centre) and crowning (centre higher) are moisture-related defects. Boards that cup during construction and then flatten once the building is conditioned are not defects if they return to within tolerance. Boards that remain cupped in the finished, conditioned building are a workmanship or specification defect.

Sanding and coating (solid hardwood)

Solid hardwood and some engineered products are sanded and coated in place after installation. The sanding and finishing process is covered by AS 4786.2 (Timber flooring: sanding and finishing) (verified 2026-05-10, Standards Australia, AS 4786.2).

Typical process:

Rough sand: 36 to 40 grit to level any board-to-board lippage and remove machine marks
Medium sand: 60 to 80 grit
Fine sand: 100 to 120 grit for final surface preparation
Edging and detail: belt or hand sanding at walls, thresholds and tight areas
Coating: two to three coats of polyurethane (water-based or solvent-based), oil, or hard-wax oil system per manufacturer’s instructions. Full cure before foot traffic (typically 24 to 72 hours per coat for water-based; longer for solvent)

Pre-finished engineered and bamboo products arrive coated from the factory. No site sanding or coating is required. Edge joints are vulnerable on pre-finished floating floors; do not allow construction traffic on pre-finished floating floors without protection sheets.

Working with other trades

Plasterer / renderer: wet trades must be complete and dry before timber flooring is installed. Residual moisture from renders and screeds can drive slab MC above the 5.5% threshold.
Painter: in nail-down floors, flooring typically goes in before final paint coat to allow scribing of skirting. In floating floors, the floor may go in after final coat; confirm sequence with the builder.
Cabinetmaker: kitchen and bathroom cabinets that sit directly on the floor (as opposed to being on a plinth) can lock the floating floor and prevent movement. Clarify whether cabinets sit on the floor or the floor runs under the cabinet plinth before ordering.
Skirting chippy: skirting is always fixed after the floor is laid. Skirting covers the perimeter expansion gap and sits against the top of the flooring. See skirting and architrave installation.
Concretor / slab finisher: slab flatness tolerance of ±3 mm over 3 m must be achieved before pour if direct-stick or batten method is specified. Shotblasting or grinding after cure is possible but adds cost and programme time.

Health and safety

Sanding dust: hardwood dust is a respiratory hazard. Use dust extraction connected to the sanding machine; wear P2 respirator during sanding and edging. Bag and remove all sanding waste; do not blow out with compressed air.
Coating fumes: solvent-based polyurethane emits VOCs. Ventilate the space during and after application. Flammable during application; no ignition sources.
Manual handling: flooring packs are heavy. Stage delivery to minimise carry distances; use mechanical handling aids.
Knee injuries: floor laying is sustained kneeling work. Knee pads and regular posture breaks reduce cumulative strain.

Suppliers

Major timber flooring suppliers and distributors in Australia include Boral Timber, Laminam, Preference Floors (engineered), Hurford Wholesale, and specialty importers. ATFA’s Find a Member directory lists accredited installers and suppliers nationally.

What can go wrong

Cupping and crowning: excess moisture from the slab, from incomplete building seal, or from inadequate ventilation during construction. Resolve the moisture source before laying.
Gapping: insufficient acclimation; floor laid in a high-humidity construction environment and then subjected to air conditioning. Gaps that are permanent and wide are a defect.
Squeaking: inadequate nailing (spacing too wide, wrong nail length); battens not fixed adequately to substrate; boards bridging hollow spots in the subfloor.
Delamination (engineered boards): moisture penetration into the core causing face veneer to separate from the structural core. Usually a substrate moisture management failure.
Sanding through the face (engineered): over-sanding a thin-face product burns through the wear layer. Confirm face thickness before committing to a sanding programme.
Coating adhesion failure: oily species (merbau, teak) require specific primers before coating. Standard polyurethane applied directly to oily timber will peel.
Expansion buckling: insufficient perimeter or intermediate expansion gaps. Floor lifts and buckles in summer/high-humidity conditions. No remedy without pulling up and relaying.

References

Australian Timber Flooring Association (ATFA): atfa.com.au (verified 2026-05-10)
ATFA Floor Choices , Acclimatisation of timber flooring: floorchoices.com.au/information-sheets/acclimatisation-of-timber-flooring/ (verified 2026-05-10)
ATFA Floor Choices , Hardwood flooring grades (AS 2796): floorchoices.com.au/information-sheets/hardwood-flooring-grades/ (verified 2026-05-10)
ATFA Floor Choices , Timber flooring systems: floorchoices.com.au/information-sheets/timber-flooring-systems/ (verified 2026-05-10)
WoodSolutions , Flooring (Forest and Wood Products Australia): woodsolutions.com.au/applications-products/interior/flooring (verified 2026-05-10)
NSW Guide to Standards and Tolerances 2017 (NSW Fair Trading): fairtrading.nsw.gov.au (verified 2026-05-10)
Standards Australia , AS 2796: Timber – Hardwood – Sawn and milled products: standards.org.au (verified 2026-05-10)
Standards Australia , AS 4786.2: Timber flooring – Sanding and finishing: standards.org.au (verified 2026-05-10)