Boron Gel & Paste Treatment
Boron paste and gel soak into thick, damp or hidden timber that a surface spray cannot reach.
- Moves into wood through moisture
- Suits joist ends and thick beams
- Lower toxicity to people than many insecticides
What boron & paste does
Boron is a mineral salt that kills wood-boring insects and many fungi. A paste or gel holds it against the timber, and it then spreads into the wood through moisture. For that reason it works best on thick or damp sections.
Boron is a good partner to spray. Spray covers the surface, while boron reaches deeper. A surveyor will often use both on a badly hit joist.
How a boron treatment runs
The steps are simple, but the timing matters because boron needs moisture to travel.
- 1
Expose the wood
The team clears the area and cuts back loose or rotten wood. Bare timber lets the paste make contact.
- 2
Apply paste or gel
A thick coat goes on the surface, often with extra at joist ends. Holes may be drilled so the product can reach the core.
- 3
Let it spread
Moisture carries boron into the timber over days or weeks. Dry timber slows the spread, so the surveyor will explain what to expect.
What to weigh up
Every method has trade-offs. Weigh them against your own timber, because no method suits every case.
Reaches deeper
Boron moves through damp wood. It can protect the heart of a thick section.
Good on joist ends
Ends set into walls are damp and hard to spray. Paste sits on them for longer.
Also acts on fungus
Boron helps against some rots as well. That is useful where beetle and damp occur together.
Limits to know
It spreads slowly in dry wood, and it can wash out if the timber stays wet. Fix the damp as well.
When this method is the right choice
Use this list to check the fit. A mismatch wastes money, since each method has limits.
- Thick joists, beams and wall plates
- Joist ends set into damp masonry
- Hidden or hard-to-reach timber where spray does not penetrate
Help in your area
This applies across the UK, but housing differs by city. For local detail, read about woodworm treatment in London and woodworm treatment in Manchester, because older streets hold more old timber.
Boron & Paste: your questions
Is boron safe?
Boron has low toxicity to people compared with many insecticides. Still, follow the product label and the specialist's written advice. Keep children and pets away until the area is dry.
Does boron work on dry timber?
It works best where the wood holds some moisture. In dry timber it spreads slowly, so a surveyor may combine it with spray.
Can I buy boron myself?
Yes, shops sell boron products for small jobs. For structural timber, read DIY vs professional treatment first.
Does boron cure damp?
No. It protects the wood but it does not stop leaks. See dry rot and damp treatment for the cause.
Helpful next steps
Not sure which method you need?
Request a survey, because the right method depends on the beetle and the timber. A local specialist will call you to arrange a visit.