Timber Deck Board Sizes 90mm vs 140mm Cost Per m2
By the Timber Decking Cost Guides Editorial Team — reviewed for accuracy. Last updated November 2026. This article is for informational purposes and reflects typical market pricing; verify current details with licensed contractors before starting any project.
The 90mm boards at $55-$90 per square metre against the 140mm at $80-$120 — a profile comparison where the coverage math and the fixing method price the difference.
This guide prices the board sizes: the per m2 coverage at the profiles, the fixing scope, and the look trade-offs at the honest comparison.
Timber Deck Board Sizes 90mm vs 140mm Cost Per m2 — At a Glance for AU
The board-size choice runs A$69–A$150 per square metre supplied — the profile width and the grade carrying the range. This is a realistic planning number for Australia in 2026, not a marketing low-ball.
| Line Item | Typical Range (AUD) | What Drives It |
|---|---|---|
| 90x19mm boards per square metre | A$69–A$110 | The standard profile at the coverage |
| 140x19mm boards per square metre | A$100–A$150 | The wide profile at the premium |
| Fixing difference per square metre | A$6.25–A$19 | The screws against the clips |
| Install labour difference | A$12–A$31 | The lineal count at the labour |
| Waste factor difference | A$3.75–A$10 | The offcut profile at the coverage |
Understanding Timber Deck Board Sizes 90mm vs 140mm Cost Per m2
The 90mm boards running $55-$90 per square metre supplied — the standard profile at the coverage math. The 140mm at $80-$120 — the wide board at the premium and the lower lineal count. The per-metre board count: 11 boards at the 90mm against 7 at the 140mm per square metre.
The fixing scope at the profiles: the 90mm at the top-screwed or the secret-fixed paths; the 140mm at the face-screws and the dual-row requirement at the wide span. The labour difference at the lineal count — the 90mm at the 40% more rows pricing the install honestly. The look trade-off: the 90mm at the traditional rhythm; the 140mm at the modern clean line.
What Moves the Price Up or Down
The price moves with the profile, the grade, the species, and the fixing method.
| Factor | Cost Impact | Detail |
|---|---|---|
| Profile width | +30-45% | The 140 against the 90 |
| Species band | +20-40% | The hardwood against the pine |
| Grade and length mix | +15-30% | The select against the standard |
| Fixing method | +5-15% | The clips against the screws |
| Waste factor | +5-10% | The offcut profile |
Board Profile Options
Two widths serve the deck — the 90mm, the 140mm trading.
| Option | Description | Best For | Cost Level |
|---|---|---|---|
| 90x19mm profile | The traditional rhythm at the coverage | The classic decks | $55-$90 per m2 |
| 140x19mm profile | The modern wide line | The contemporary decks | $80-$120 per m2 |
| Mixed feature borders | The 90 and the 140 at the design | The character builds | Either band plus the layout |
The 90mm serving the classic rhythm — the 140mm serving the contemporary line at the premium.
Three Realistic Project Scenarios
The classic 90mm build — A$6,880–A$10,940
A 25 square metre merbau deck at the standard profile.
- 90mm boards — A$1,720–A$2,810
- Frame and labour — A$5,160–A$8,120
Why this matters: The classic path serves the rhythm — the 25 m2 at the $7,100 total with the 11-row coverage.
The contemporary 140mm build — A$7,810–A$11,880
A 25 square metre wide-board deck.
- 140mm boards — A$2,500–A$3,750
- Frame and labour — A$5,310–A$8,120
Why this matters: The contemporary path serves the line — the 25 m2 at the $7,900 total with the 7-row coverage.
The feature-border mix — A$8,500–A$12,750
A 25 square metre deck at the 140 field and the 90 border.
- Mixed boards — A$2,880–A$4,310
- Frame and labour — A$5,620–A$8,440
Why this matters: The mixed path serves the character — the field and the border at the layout premium honestly.
The scenarios share the frame and the species — the profile coverage and the row count separating the totals.
Sample Budget Breakdown
The table below shows how a typical mid-range budget for timber deck board sizes 90mm vs 140mm cost per m2 distributes across materials, labor and compliance in Australia. Adjust the percentages to your own scope before using it as a savings target.
| Category | Estimated Amount | Explanation | Optimization Tip |
|---|---|---|---|
| Boards supplied | A$1,720–A$4,310 | The profile at the band | The single batch |
| Fixings and clips | A$160–A$470 | The profile fixing scope | The method matched to the width |
| Frame and licensed labour | A$5,160–A$8,440 | The install scope | The row count at the labour |
| Contingency | A$250–A$750 | The offcut profile | The waste factor honestly |
Every figure above is an indicative 2026 market range. Final quotes move with site conditions, contractor availability and the exact specification you lock in.
From Quote to Completion: the Typical Timeline
Most timber deck board sizes 90mm vs 140mm cost per m2 projects follow the same five-stage rhythm. Knowing the calendar before you sign prevents the two classic frustrations — feeling rushed into a deposit, and being surprised by a mid-project gap while materials arrive.
- Timber delivery and acclimatisation — 1-2 weeks
- Frame and board install — 1-2 weeks typical
- Final oil coat and handover — 2-4 weeks after install
- Design and quoting — 2-4 weeks
- Timber delivery and acclimatisation — 1-2 weeks
Smart Ways to Control the Budget
Cost control on timber deck board sizes 90mm vs 140mm cost per m2 is mostly about scope discipline and timing. These are the strategies that consistently deliver the largest savings:
Time the install for the shoulder season
The spring and autumn install windows at the standard rates — the summer rush pricing the 15-25% premium at the peak. The winter quoting serving the honest availability and the off-season rate cards.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- Requires the booking at the quiet season.
- Requires planning lead-time you may not have on urgent timelines
Match the fixing to the board width
The secret-fixed 90mm boards at the hidden fasteners pricing the clean surface; the top-screwed 140mm boards at the visible fixings serving the budget. The fixing method priced against the aesthetic priority honestly.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- The fixing decision before the board order.
- Requires planning lead-time you may not have on urgent timelines
Price the species by the lifespan, not the sticker
Merbau at $55-90 per square metre supplied against the treated pine at $25-40 — the 25-year hardwood lifespan against the 10-15 year pine cycle. The total ownership math pricing the honest comparison over the decades, not the build day.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- Requires the decades framing at the timber yard.
- Requires planning lead-time you may not have on urgent timelines
Buy boards in the one moisture-stabilised batch
The single-batch supply at the consistent moisture content pricing the even gaps — the mixed batches shrinking unevenly and producing the irregular spacing. The batch number recorded at the delivery docket.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- Takes the full-quantity order at the one delivery.
- Requires planning lead-time you may not have on urgent timelines
Permits, Rules and Safety
Both profiles at the same permit path — the structure at the review. The board width at the aesthetic scope, not the code.
- (‘Pool zone compliance check’, ‘$0-250’, ‘The pool-adjacent decks at the CPRC non-climbable zone review — the barrier code at the pool vicinity scope.’, ‘Applies at every deck within the pool zone.’)
- (‘Setback and boundary review’, ‘$0-150’, ‘The boundary clearances at the site plan — the attached structures at the easement and the setback rules.’, ‘The site plan checked at the quoting stage.’)
- (‘Deck permit’, ‘$100-400 typical in AU councils’, ‘The structural review at the footings, the frame, and the balustrade code — the over-1-metre heights and the pool zones always at the permit scope.’, ‘The unpermitted deck pricing the resale disclosure.’)
Maintenance and Long-Term Ownership Costs
The project price is only the first line of the budget. These recurring items are what owners in Australia actually spend money on after the crews leave:
| Task | Frequency | Typical Cost | Why It Matters |
|---|---|---|---|
| Deck oil | Every 12-18 months | $4-8/sq m | The timber hydrated at the oiling cycle — the neglect pricing the grey restoration at the multiple of the maintenance. |
| Fastener and joist check | Yearly | $0-150 | The screws and the hangers at the movement cycle — the structural issues caught at the walk. |
| Inspection walk | Yearly | $0-250 | The structure, the fasteners, and the gaps walked at the season — the issues caught at the early stage. |
| Deck wash | Yearly | $100-300 | The surface grime and the mildew at the gentle wash — the coating adhesion protected at the clean surface. |
The oiling cycle at the surface area — the profiles at the same square-metre maintenance. The 140mm at the wider movement checks at the seasons honestly.
Frequently Asked Questions
Is 140mm decking more expensive than 90mm?
The 140mm at $80-$120 per square metre against the 90mm at $55-$90 — the profile premium at the coverage and the lower row count honestly.
How many decking boards per square metre?
The 11 boards at the 90mm profile against the 7 at the 140mm — the 5mm gap at the spacing. The lineal count pricing the labour honestly.
Do wide decking boards warp more?
The wider boards at the greater movement potential — the end-matching and the fixing rows at the 140mm spec. The acclimatisation serving both profiles honestly.
Which board width looks better?
The 90mm at the traditional rhythm and the detail; the 140mm at the modern clean line. The aesthetic at the honest preference scope.
Does board width change the install cost?
The 90mm at the 40% more rows pricing the labour — the 140mm at the premium board and the lower count. The totals running closer than the sticker honestly.
Summary
Planning timber deck board sizes 90mm vs 140mm cost per m2 in Australia starts with an honest range — A$69–A$150 for the scenarios most households actually install — then works backwards through the profile that sets the coverage, the row count that prices the labour, and the look that carries the decision.
The 90mm serving the classic rhythm — the 140mm serving the contemporary line at the honest premium. Collect at least three itemised quotes, confirm the permit path before signing, and hold a 10–15% contingency for site surprises. Those three habits protect more budget than any product choice.
