For more information call
01403 210204

Timber Treatment: How to treat indoor & outdoor wood

Timber is a versatile and visually appealing construction material. Despite its flexibility and resilience, timber is vulnerable to different types of degradation, from damp to woodworm infestation. Read on to find out how to treat indoor and outdoor wood with the correct type of timber treatment.

Check out standard timber treatment approaches for these common problems:

Call or submit an enquiry if you need help solving any timber treatment problems or would like to find a qualified surveyor.

Common timber damaging problems include but are not limited to:

  • Woodworm infestation
  • Bowed, kinked or otherwise warped timber
  • Wet and dry rot
  • Other biological growth like mould and fungus

The treatments required to fix or prevent timber damage vary depending on many variables:

  • Moisture levels
  • Environment
  • Wood-boring beetle presence
  • Fungal or mould infestation

Frequently Asked Questions

  • What is the best treatment for timber?
    To prevent timber damage, Liquid Wood Preservatives like Roxil Clear & Coloured Wood Protection Liquid provides robust waterproofing and biocidal protection.

  • What are the different treatments for timbers?

    • Consumer Liquid Wood Preservatives (Roxil Clear & Coloured Wood Protection Liquid)

    • Silicone-based Wood Cream (Roxil Wood Protection Cream)

    • Professional-grade Preservatives (ProBor Borate Professional Wood Preservative)

    • Decking Oils (Roxil Enhanced Decking Oil)

  • What is the best treatment for wood outside?
    Roxil Wood Protection Cream provides comprehensive waterproofing protection, making it perfect for exposed outdoor sheds, chairs and tables.

  • What can you put on wood to keep it from rotting outside?
    Soluguard Woodworm and Rot is a water-based formulation that protects timber from white and brown rot. It destroys all stages of the woodworm lifecycle. Wood preservers and silicone-based creams also prevent wood rot by waterproofing. Roxil Wood Preserver provides protection against wood-eating fungi.

Dry and warm – the fundamental elements of timber care

The best way to keep timber in good condition is to keep it in a dry and warm environment. Prior to further treatment, ensure that any timber structure, furniture or ornamental piece is in as dry and warm an environment as possible.

Biocidal timber treatments

Biocidal timber treatments are commonly applied to timber to prevent rot or mould problems from occurring. Increasing regulation on the use of biocides in outdoor environments means that modern silicone-based treatments can often provide a better solution to biological growth on timber.

Damp and wood rot

Damp environments put timber at risk of wood rot. Rot weakens wooden structures and causes significant damage. Rotten structural elements like floor joists, floorboards or structural timbers pose a serious threat to building occupants.

Dry rot on a wooden board

Preventative, not curative

Rotten timber cannot be cured. Even professional-use biocidal treatments are classified as preventative under the European Biocidal Products Regulation and will not ‘cure’ infested wood. Any rotten wood will need to be removed and replaced during the course of treatment. Once the timber is clear of rot, biocidal treatment prevents future infestation.

Indoor Environments

In indoor environments, it is essential to determine if you are dealing with wet rot or the more serious dry rot. All suspected rot infestations should also be investigated by a professional to prevent misdiagnosis.

Wet rot treatments

More about wet rot

Indoors, wet rot treatment involves:

  • Removing infested wood
  • Removing the causes of moisture
  • Ensuring the environment remains dry.

Removing the causes of moisture usually involves fixing a leak or solving an underlying rising, penetrating and condensation-causing damp problem.

Treating the surrounding timber with Soluguard Woodworm & Rot Treatment is a preventative action to be applied once the wet rot has been removed and its causes have been treated.

Probor Wood Preservative range

Dry rot treatment

Learn more about Dry rot

Dry rot should always be treated by a professional who has a deep understanding of the biology of dry rot and access to the appropriate treatment materials like the Probor Wood Preservative range, which is only available to professional users.


Dry rot can cause widespread structural damage. We recommend that a professional timber treatment company is called in to carry out a survey if dry rot is suspected. If you suspect dry rot, please contact our technical department on 01403 210204 or submit an enquiry and we will be happy to arrange for an experienced timber treatment company to contact you.

Outdoor Environments

As with interior timber, preventing wood rot is always the best course of action to protect exterior timber.

For wood in typically exposed environments, minimise the risks of rot with Roxil Wood Protection Cream. The colourless silicone-based coating soaks deeply into timber to protect it from moisture ingress for 10+ years without staining it. By keeping the wood dry, it will be more difficult for rot fungal spores to take root in the wood.

If the external timber structure is at high risk of rot infestation due to placement in a shaded or very moist area, a coat of Soluguard Woodworm & Rot Treatment can be applied to the timber by brush before carrying out the Roxil Wood Protection Cream application. Soluguard Woodworm & Rot Treatment is fully compatible for use as an undercoat to Roxil Wood Protection Cream.


How to treat woodworm

Unlike when treating rot, woodworm infestations can be treated both curatively and preventatively. A certified surveyor must diagnose any wood-boring beetle infestation. Due to the damage they can cause, certain types of woodworm must be treated by professionals

Most active infestations can be treated without the need to replace or remove the affected timber, although this depends on the condition of the affected timber.

It is also worth noting that woodworm holes may just be a sign of a previous infestation that is no longer active. For a more detailed look at the different types of woodworm, refer to our Woodworm Identification & Treatment guidebook.

Damage caused to wood by Deathwatch Beetles

Indoor Environments

Woodworm infestations indoors are almost exclusively done using biocidal liquids. Whether the infestation is currently active or there is just evidence of prior woodworm activity, Soluguard Woodworm Treatment is the best method of treatment. Its powerful formula kills any live beetle larvae and prevents future infestation for at least five years.

Outdoor Environments

In outdoor environments, woodworm is found in very damp environments. In the wild, woodworm larvae typically feed on damp rotten or dead wood on forest floors. Dry wood is undesirable to woodworm due to its hardness. Roxil Wood Protection Cream protects exterior timber from moisture ingress, drastically reducing the chances of a woodworm infestation.

If external timber has already been infested with woodworm and the infestation is still active (or suspected to still be active) then an application of Soluguard Woodworm & Rot Treatment should be carried out as an undercoat before the application of Roxil Wood Protection Cream. The Soluguard Woodworm & Rot Treatment will kill any woodworm already present in the wood and the Roxil Wood Protection Cream will help to keep the wood dry and further discourage future infestations.

Warping & Cracking

Wood expands as it gets wet. Timber expansion causes problems in wooden structures, resulting in warping and worse. Natural wetting and drying cycles from seasonal changes can result in serious issues like joint cracks and splits over time.

Garage with rustic warped wooden shingle gable end wall

Mould or rot spores get into splits and cracks in timber, bypassing biocidal surface treatments to cause rot.

Wood warping is common outdoors due to rain exposure. Warped wood inside a building is a sign of an unusually humid or damp environment. Efforts should always be made to isolate timber from any sources of dampness. Appropriate ventilation measures should be installed and heating facilities assessed.

Outdoor wooden structures are far more likely to be affected by warping due to exposure to the elements. Roxil Wood Protection Cream stops moisture ingress to improve dimensional stability, reducing the likelihood of warping, cracking or splitting.

Surface Mould & Algae Growth

Even well-maintained wooden surfaces get dirty over time. Surface condensation or pooling water quickly leads to indoor and outdoor surface mould and algae growth. This form of biological growth is largely an aesthetic consideration. To remove dirt, mould and algae use a biocidal cleaner.

Roxil 100 Wood & Patio Cleaner being spray applied to a wooden fence panel

For indoor wooden surfaces, Dryzone 100 Mould Remover removes all mould and dirt. On outdoor wooden surfaces, Roxil 100 Wood & Patio Cleaner is a liquid-based cleaner that leaves patios pristine. Both of these cleaners are biocidal, killing the mould and minimising regrowth.

Unlike competing wood cleaners, Dryzone 100 Mould Remover and Roxil 100 Wood & Patio Cleaner are non-destructive. For outdoor structures, Roxil Wood Protection Cream keeps wood surfaces dry to reduce mould growth significantly. Any surface growth remaining can be easily cleaned away using Roxil 100 or Dryzone 100 cleaners.

For more information call
01403 210204