A grade letter tells you nothing about termites

Termite damage is the failure people notice last. Water damage announces itself — a swollen edge, a lifting laminate. Insects work from the inside, quietly, often for years, and the first sign is usually a shelf that gives way under a load it carried yesterday.

The good news is that this is a solved problem. The catch is that the solution is invisible, which means you have to ask about it rather than look for it.

The key point: grade tells you nothing about this

A board's grade — MR, BWR, BWP, Marine — is a statement about the glue and how it behaves in water. It says nothing whatsoever about whether the timber inside resists borers, termites or fungal decay.

This surprises people, and it is worth stating plainly: a Marine-grade board is not automatically termite-proof. Water resistance and pest resistance are two separate properties, achieved by two separate means.

So "which grade resists termites?" is the wrong question. The right one is: "how was this board treated, and does the treatment penetrate?"

What attacks plywood

Powder-post beetles and borers. These lay eggs in timber; the larvae tunnel through it, feeding on starch in the wood. The tell-tale sign is fine powder — frass — collecting below small round exit holes. They favour sapwood, which is exactly the material used in core veneers.

Termites. Colony insects that consume cellulose. Subterranean species reach furniture from the ground, often via mud tubes along a wall, and can enter through a single point of contact between furniture and floor or masonry.

Fungal decay. Not an insect, but it belongs in the same conversation because the same conditions favour it and the same preservatives address it. Fungi need sustained moisture — which is why decay and water problems arrive together.

All three are more active in warm, humid conditions, which describes most of India for much of the year.

Penetrating treatment vs surface coating

This is the distinction that decides whether treatment works.

Surface coating. A preservative applied to the outside of a finished board — sprayed or brushed on.

Why it disappoints:

• It wears away with handling, sanding and finishing.
• Every cut exposes untreated core. The moment a carpenter rips a sheet, the new edge has no protection at all — and a board gets cut many times in a normal job.
• It cannot reach the interior, which is where borers do their damage.

Penetrating treatment. The board is immersed in a preservative bath so the chemical goes into the board rather than sitting on it.

Why it works:

• The protection is distributed through the board, not just at the surface.
• Cut edges remain protected, because the interior was treated too.
• It does not wear off with handling or finishing.

Lennor boards are dipped in an ACC preservative bath as a dedicated station on the production line — a stage in manufacturing rather than a finishing touch applied at the end.

What ACC treatment is. ACC stands for acid copper chromate, a waterborne wood preservative. Copper is the primary fungicide and insecticide; chromium fixes the compound into the wood so it resists leaching out when the board gets wet.

That fixing property is the practically important part: a preservative that washes out over a few damp seasons offers protection that expires. One that binds into the timber does not.

Preservative treatment for timber and plywood in India is covered by Indian Standards, and specific retention levels, chemical concentrations and compliance details for a given product should be confirmed with the manufacturer rather than assumed — for Lennor's specifications, contact us.

What to ask a supplier

Since you cannot see treatment, ask. Five questions:

1. "Is this board treated against borers and termites?" A surprising number of economy boards are not.
2. "What preservative, and at what stage of manufacturing?" A named chemical and a production stage is a real answer. "It's treated" is not.
3. "Does the treatment penetrate, or is it applied to the surface?" The single most useful question here.
4. "Will cut edges still be protected?" This follows from question 3, and it is worth asking explicitly because it is where surface treatment fails.
5. "Is treatment applied to all grades, or only the premium ones?" Some manufacturers treat only their higher grades. Since MR grade goes into bedrooms — where borer damage hides behind stored clothes for years — this matters.

What you can still do on site

Treatment is the foundation, not the whole answer. Four site practices meaningfully reduce risk:

Seal cut edges. Primarily a moisture measure, but a sealed edge is also a less attractive entry point.

Break ground contact. Subterranean termites reach furniture through contact with floors and walls. Raise carcasses on a plinth, and leave an air gap behind furniture on exterior walls.

Control moisture. Damp timber is more attractive to both insects and fungi. Ventilation, edge sealing and keeping furniture off wet floors all help.

Inspect occasionally. Look behind and beneath built-in furniture once a year for fine powder, small round holes or mud tubes. Caught early, an infestation is a treatable nuisance; caught late, it is a rebuild.

Signs of an existing problem

• Fine, flour-like powder collecting below furniture or on shelves.
• Small round exit holes, roughly 1–2 mm across.
• Mud tubes running up a wall or along a skirting toward furniture.
• A hollow sound when a panel is tapped.
• A shelf or panel that gives way under a normal load.

If you find these, treat the infestation as a pest-control problem first. Replacing the board without addressing the source repeats the outcome.

A note on buying claims. "Termite-proof" is a strong word, and it is used loosely. No timber product is permanently immune under every condition — what good treatment provides is durable, distributed resistance that does not wash out or wear off.

Be sceptical of:

• "Termite-proof" with no named treatment. Ask what and how.
• Treatment described only for the premium range. Ask about the grade you are buying.
• A grade letter offered as evidence of pest resistance. They are unrelated properties.

What Lennor does

Every board, in every grade, passes through an ACC preservative dip as one of the sixteen stations on the line in Hassan — not only the premium grades. The treatment penetrates rather than coating the surface, so cut edges made on site remain protected.

Because the stage sits within the production line rather than at the end of it, it applies to boards, block boards and flush doors alike. Architects and bulk buyers are welcome to see the treatment stage on a line visit.

Questions we get asked

Which plywood grade is termite-resistant? None inherently. Grade describes the glue's water resistance. Pest resistance comes from preservative treatment, which is a separate process applied independently of grade.

What is ACC-treated plywood? Plywood immersed in an acid copper chromate preservative bath so the chemical penetrates the board. The copper provides insecticidal and fungicidal action; the chromium fixes it into the wood so it resists leaching.

Is marine plywood termite-proof? Not automatically. Marine grade describes an undiluted phenolic bond and a dense core. Ask separately about preservative treatment.

Does termite treatment wear off? A surface coating does — with handling, sanding and cutting. A penetrating treatment fixed into the timber does not, which is why the method matters more than the fact of treatment.

How can I tell if plywood is treated? You cannot tell by looking. Ask what preservative was used, at what stage, and whether it penetrates. Vague answers are themselves informative.

Can I treat plywood myself after buying it? Surface-applied products exist and offer limited protection, but they cannot reach the interior and will not protect cuts made afterwards. Factory treatment applied before the board is finished is far more effective.

Do termites attack plywood as readily as solid wood? Both are cellulose and both are vulnerable if untreated. Core veneers often use sapwood, which insects prefer — which is exactly why treatment during manufacture matters.

Talk to us

Ask us what our boards are treated with and at what stage — or come and watch the treatment station on the line.

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