In-Ground Paste
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Timber Protection

In-Ground Paste

A high-strength preservative paste for timber in ground contact — posts, poles and stumps at the groundline, the zone that rots first.

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300 g, 3.3 kg and 18 kg Schedule 5 — CAUTION APVMA 60903

↓ Safety Data Sheet

Protects against: Decay at the groundline — field-tested for over 10 years
Use on: Posts, poles and stumps in ground contact; cuts and boltholes
Format: Copper paste. Trowel, brush, cartridge or pump.
Colour: Turns treated timber dark brown to black

Not sure it's the right product? Compare preservatives or call 03 9532 0679.

Directions for use

Preparing the timber, then applying — as per the approved label

Structural or load-bearing timber? Veranda posts, bearers, joists, rafters: get a qualified professional to decide whether it can be treated or needs replacing. Preservative stops decay spreading; it can't restore lost strength.

Before you apply

Expose the groundlineFor an existing post, dig around the base to expose the band just above and below the soil line — that's the zone that needs treating.
Remove soil & decayed woodClear soil and debris off the timber, and scrape back any soft, decayed surface to sound wood before applying. For ground contact, remove all non-pressure-treated sapwood.

Supplementary, not a substituteIn-Ground Paste protects the groundline zone — it doesn't turn untreated timber into in-ground-rated timber. For new posts, start with correctly treated timber.

Applying the paste

Always read the label before use.

Trowel or brush on the groundlineApply by trowel, heavy brush, cartridge or mechanical pump. For pole groundline treatment, apply an even coat at least 6 mm thick — from roughly 450 mm below ground to 1100 mm above ground. End grain and pile tops: up to 6 mm; timber joints: up to 3 mm before joining.
Bandage over the pasteFor groundline work, wrap a wax- or plastic-coated paper (or light plastic) bandage around the pole over the paste. This maximises absorption into the pole and significantly enhances performance.
Let it skin and absorbOn exposure to air the emulsion darkens and forms a skin within hours; the oil keeps absorbing along the grain. Treated timber turns dark brown to black. Absorption may take up to two weeks out of ground contact.

Application rate

Groundline coat thickness and band.

Where	Thickness
Pole groundline — 450 mm below to 1100 mm above ground	≥ 6 mm
End grain and pile tops	up to 6 mm
Timber joints, before joining	up to 3 mm

Ready to use — stir before applying. Clean up with warm water and detergent.

CAUTION · As per the approved label

Safety & hazards

Signal word, restraints and first aid — from the approved label

As per the approved label. Always read the label before use.

Schedule 5 — CAUTION

May irritate eyes and skin.

Wear oil-resistant gloves. Excessive contact can cause dryness and mild skin irritation. Use eye protection when working overhead or with pressurised application. Wash hands with soap and water after use.

First aid

If poisoning occurs, contact a Doctor or Poisons Information Centre (13 11 26). If swallowed, do NOT induce vomiting — rinse mouth and give a glass of water.

Full safety directions and first aid are on the product label and the Safety Data Sheet.

Handling & environment

Preschem handling guidance — general advice, not label text. The approved label and the Safety Data Sheet take precedence.

Flammability

Combustible (flash point 180 °C). Avoid heat, sparks and open flame.

Environment

Avoid contaminating waterways and sewers — the product forms an oil pollution hazard.

Staining

Will stain clothing and animal hair (e.g. wool).

Where it goes

At and below the groundline, and on cut surfaces

Wherever timber meets the soil, or where a cut or bolthole exposes untreated wood to moisture. Apply to the groundline zone — roughly the band from just above the soil to just below it.

Fence & verandah postsAt the groundline, where the post enters the soil and stays wet.

Poles & stumpsThe soil-line band on poles and house stumps — the zone that fails first.

Cut tops of posts & pilesWhere a post or pile has been cut to length, exposing untreated end grain.

Boltholes & fixing pointsDrilled holes and joints in in-ground timber that expose untreated wood.

Retaining-wall postsThe in-ground portion of landscape and retaining timber.

Near plants & animalsThe label allows use on timber in contact with plants or animals.

Built to stay put at the groundline

Why it works

In-Ground Paste carries the highest copper load in the range, in a paraffin base that clings to the timber surface rather than draining away — so the protection stays where you put it, at the wet soil-line where decay is worst.

Highest copper load

A concentrated copper naphthenate paste — far stronger than the brush-on preservatives, because the groundline is the hardest-working zone on any post.

Clings where it's put

The paraffin base means it stays on the surface as a reservoir and keeps protecting for over a decade in ground contact, rather than being washed away by soil moisture.

Made for ground contact

The one product in the range for timber that meets the soil — where every above-ground preservative stops.

Technical data

Specifications

Active constituents

Copper naphthenate 10–30%, in a paraffin oil base (30–60%), with ammonium hydroxide (<1%) and water — a water-based emulsion paste. The highest copper load in the range.

Rate, coverage & reapplication

Groundline coat at least 6 mm thick, ~450 mm below to ~1100 mm above ground. Field-tested to protect against decay in ground contact for over 10 years. Re-inspect at 5 years; re-apply at least every 10 years in most cases.

Pack sizes

300 g, 3.3 kg and 18 kg.

Poison schedule

Schedule 5 — CAUTION. May irritate eyes and skin.

APVMA registration

APVMA 60903. Distributed by Thomson White Australia.

Storage & shelf life

Store in the closed container in a secure place, out of reach of children. Avoid exposing containers to heat or strong sunlight — temperatures above 40 °C can break down the emulsion.

Common questions

How long does it last?

It's been field-tested to protect against decay in ground contact for over 10 years. Re-inspect at about five years, and re-apply at least every ten in most situations.

What's the bandage for?

Wrapping a wax- or plastic-coated paper bandage around the pole over the paste holds the treatment against the timber, which maximises absorption into the pole and significantly enhances performance. It's specific to groundline work and worth doing.

Can I use it on new posts?

Yes, but it's a supplementary treatment — it protects the groundline zone, it doesn't turn untreated timber into in-ground-rated timber. Start with correctly treated timber and use the paste to protect the zone that works hardest.

How do I clean up?

Warm water and detergent — it's a water-based emulsion, so it doesn't need turps like the oil-carried brush-on preservatives.

You might also need

Heavy Oil Preservative

For the above-ground part of the same post — heavy-duty copper protection for weather-exposed timber.

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Australian made in Cheltenham, Victoria since 1988 — founded by two CSIRO timber scientists. The whole story →