How Long Does Woodworm Treatment Last?

Many people ask how long woodworm treatment lasts. There is no single answer, because it depends on the method, the timber, the beetle and whether the damp is fixed. This guide explains what to expect.

What affects how long it lasts

Five things matter most:

• The method. Spray protects the surface, while paste reaches deeper.
• The coverage. Untreated wood can still be attacked.
• Damp. Wet wood invites beetle back.
• The beetle. Some species are harder to clear.
• Ventilation. Dry, airy voids are safer.

Spray

A spray treatment leaves insecticide in the outer wood. Emerging beetles meet it and die, which stops new holes. Protection lasts while the product stays active, yet it does not last for ever.

Paste

Boron paste moves into the wood through moisture. It can protect thick timber for longer, as long as the wood is not washed out by repeated wetting.

What a guarantee means

Some firms offer a written guarantee. The terms differ, so read them. Check what it covers, how long it runs and what voids it. Ask who stands behind it if the firm stops trading.

We do not offer a guarantee ourselves, because the firm that treats the wood issues it. Our page on guarantees lists the questions to ask.

Why beetle sometimes returns

Beetle returns for three common reasons:

1. The damp was not fixed
2. Some timber was missed or hidden
3. New untreated wood, such as furniture, was brought in

The first reason is the biggest. Beetle prefers damp wood, so a leak undoes the work. For more, see the guide to how quickly woodworm spreads.

How to tell if treatment worked

Watch the wood for a season. Vacuum the dust and check for new dust or holes in summer. Old holes stay, but new ones should stop. Our guide to active versus historic woodworm explains the test.

How to make it last

Take these steps, since small habits keep the wood dry:

• Fix leaks and clear air bricks
• Keep floor and roof voids ventilated
• Seal bare wood with paint or varnish
• Inspect lofts and floors each spring
• Keep your quote and treatment records

If beetle returns

Contact the firm in writing and keep a copy. Ask for a visit and a written reply. If the damp is the cause, fix it first, because retreatment alone will not last.

Next steps

If you are unsure whether treatment is needed, request a survey. You can also read how to treat woodworm.

Local housing changes the risk. Read about woodworm treatment in Edinburgh and woodworm treatment in Cardiff to see what affects homes in each area.

To go deeper, read about the spray treatment and the boron paste treatment, because the right method depends on the beetle.