Deck Tannin Leach Staining Fix Cost New Merbau
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 tannin-leach fixes running $5-$25 per square metre — the wash scope and the stained-surface removal deciding the honest band at the new merbau.
This guide prices the leach scope: the pre-install wash, the stain removal from the pavers, and the prevention at the first-coat timing.
Deck Tannin Leach Staining Fix Cost New Merbau — At a Glance for AU
The tannin-leach fix runs A$6.25–A$31 per square metre at the deck scope — the wash and the stained surfaces 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 |
|---|---|---|
| Pre-install tannin wash | A$3.75–A$10 | The boards at the leach reduction |
| Oxalic acid treatment | A$2.5–A$7.5 | The stain removal at the surfaces |
| Paver and concrete stain removal | A$6.25–A$19 | The hard surfaces at the leach marks |
| First-coat early oiling | A$2.5–A$6.25 | The sealing at the leach prevention |
| Runoff management scope | A$1.25–A$5.0 | The water paths at the protection |
Understanding Deck Tannin Leach Staining Fix Cost New Merbau
The pre-install wash running $3-$8 per square metre — the tannin reduction at the board prep. The oxalic treatments at $2-$6 serving the stained surfaces. The paver removals at $5-$15 at the hard-surface marks honestly.
The leach mechanism: the merbau tannins water-soluble at the first wet seasons — the dark staining at the pavers and the walls below. The first-coat timing at the prevention — the early oiling sealing the boards before the rain. The runoff management at the water paths protecting the surfaces honestly.
What Moves the Price Up or Down
The price moves with the leach scope, the stained surfaces, the wash depth, and the prevention timing.
| Factor | Cost Impact | Detail |
|---|---|---|
| Leach severity | +30-50% | The fresh batches at the tannins |
| Stained surface type | +20-40% | The pavers against the walls |
| Wash scope | +15-30% | The boards at the pre-install |
| Runoff complexity | +10-20% | The water paths at the site |
| Prevention timing | +10-15% | The first coat at the early window |
Tannin Leach Fix Options
Two stages serve the leach — the wash, the removal trading.
| Option | Description | Best For | Cost Level |
|---|---|---|---|
| Pre-install wash path | The boards at the tannin reduction | The new builds | $3-$8 per m2 |
| Post-stain removal path | The oxalic and the paver scope | The stained surfaces | $5-$25 per m2 combined |
| Prevention path | The early first coat and the runoff | Either stage | $2-$9 per m2 in prevention |
The wash serving the new builds — the removal serving the stained at the honest scope.
Three Realistic Project Scenarios
The new-build prevention — A$190–A$490
A 30 m2 deck at the pre-install wash and the early coat.
- Wash and early oil — A$190–A$490
Why this matters: The prevention path at the new build — the 30 m2 at the $270 total with the leach reduced honestly.
The paver stain removal — A$120–A$380
A 20 m2 paved area at the leach marks.
- Oxalic and cleaning — A$120–A$380
Why this matters: The removal path at the pavers — the 20 m2 at the $200 total with the oxalic scope.
The full combined fix — A$440–A$940
The 30 m2 deck and the paver scope together.
- Deck scope — A$190–A$490
- Paver scope — A$250–A$450
Why this matters: The combined path at the full — the deck and the surfaces at the $550 total honestly.
The scenarios share the leach mechanism — the stage and the surface scope separating the totals.
Sample Budget Breakdown
The table below shows how a typical mid-range budget for deck tannin leach staining fix cost new merbau 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 |
|---|---|---|---|
| Tannin wash and prep | A$110–A$300 | The boards at the reduction | The new builds at the scope |
| Stain removal scope | A$120–A$380 | The surfaces at the marks | The oxalic at the product |
| First-coat prevention | A$75–A$190 | The early oil at the sealing | The timing at the window |
| Runoff management | A$38–A$150 | The water at the paths | The surfaces protected 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 deck tannin leach staining fix cost new merbau 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.
- Coating application — 1-2 days
- Cure and furniture return — 2-3 days
- Inspection and quote — 1 week
- Clean and prep — 1-2 days
- Coating application — 1-2 days
Smart Ways to Control the Budget
Cost control on deck tannin leach staining fix cost new merbau is mostly about scope discipline and timing. These are the strategies that consistently deliver the largest savings:
Bundle the rail and the deck at the same crew
The handrail sanding and reoiling at the $15-30 per lineal metre — the same crew, the same day, the single callout. The separate visits pricing the mobilisation twice honestly.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- The bundled scope at the one booking.
- Requires planning lead-time you may not have on urgent timelines
Oil before the grey, not after
The 12-18 month oiling cycle at the $4-8 per square metre keeping the timber hydrated — the grey weathering pricing the full $25-45 restoration instead of the maintenance coat. The calendar at the maintenance plan, not the damage stage.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- Requires the seasonal discipline at the reminder.
- Requires planning lead-time you may not have on urgent timelines
Price the prep before the coating
The clean, the sand, and the tannin treatment at the $8-15 per square metre before the first oil coat — the coating over the grime and the old stain pricing the peeling failure. The preparation quoted as its own scope.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- The prep line itemised before the coating quote.
- Requires planning lead-time you may not have on urgent timelines
Test the oil on an offcut first
The $60-120 test tin at the hidden board or the offcut — the merbau tannins and the prior coatings shifting the colour from the chart. The sample approved before the 20-litre commitment.
Advantages:
- Directly reduces the controllable parts of the quote
- No impact on quality or compliance when scoped correctly
Disadvantages:
- Takes the patience at the colour decision.
- Requires planning lead-time you may not have on urgent timelines
Permits, Rules and Safety
No permit at the leach scope — the chemical and the coating outside the triggers. The runoff and the disposal at the honest handling.
- (‘No permit at the maintenance scope’, ‘$0’, ‘The like-for-like coating, the board swaps, and the sanding running outside the permit triggers — the structural changes always at the review scope.’, ‘The coating and the board replacement exempt at the structural-unchanged condition.’)
- (‘Balustrade upgrade trigger’, ‘$0-500’, ‘The balustrade code at the 1-metre height line — the replacement rails meeting the current standard even at the repair scope.’, ‘The height verified at the repair quote.’)
- (‘No permit at the maintenance scope’, ‘$0’, ‘The like-for-like coating, the board swaps, and the sanding running outside the permit triggers — the structural changes always at the review scope.’, ‘The coating and the board replacement exempt at the structural-unchanged condition.’)
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 |
|---|---|---|---|
| Mould treatment | As needed | $50-200 | The shaded and the damp sections at the mould scope — the ventilation issue fixed at the cause, not the symptom. |
| Coating inspection | 6-12 months | $0 | The water-beading test at the surface — the coating failure caught at the early stage, before the greying. |
| Gap cleaning | Quarterly | $0-100 | The debris cleared from the board gaps — the drainage and the airflow preserved at the routine. |
| Reoil cycle | 12-18 months | $4-8/sq m | The maintenance coat at the scheduled window — the full restoration avoided at the honest calendar. |
The leach at the first 12-18 months declining with the seasons — the first coats at the sealing. The staining at the surfaces managed at the annual scope honestly.
Frequently Asked Questions
Why is my new merbau deck staining the pavers?
The water-soluble tannins at the first wet seasons — the dark marks at the surfaces below. The pre-wash and the early coat at the honest prevention.
How do I remove tannin stains from pavers?
The oxalic acid and the dedicated cleaners at $5-$15 per square metre — the dwell and the rinse at the honest method. The sealed pavers at the easier path.
Can I stop merbau from leaching tannins?
The pre-install wash at the reduction; the first coat at the sealing — the full prevention at the honest limits. The leach declining at the seasons.
How long does merbau tannin leaching last?
The first 12-18 months at the declining rate — the heaviest at the first wet season. The early coats at the reduction honestly.
Will tannin stains go away on their own?
The weathering at the partial fade — the full removal at the chemical scope. The sealed surfaces at the easier turnaround honestly.
Summary
Planning deck tannin leach staining fix cost new merbau in Australia starts with an honest range — A$6.25–A$31 for the scenarios most households actually install — then works backwards through the stage that sets the scope, the surfaces that price the removal, and the timing that carries the prevention.
The wash serving the new builds — the removal serving the stained at the honest fix. 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.
