Timber Treatment & Services

Arnold Laver can offer a range of industrially applied preservative and fire retardant timber pre-treatments for timbers being used either indoors or outdoors.

Preservative Treatments – TANALISED™ Timber & VACSOL™ Aqua Treated Timber

Preservative pressure treatments will significantly extend the service life of construction and landscaping timbers by providing an effective long term protection against all forms of wood decay and insect attack.


Carried out in our own industrial treatment vessels by trained operators, our treatments utilise the very latest TANALITH™ E and VACSOL™ Aqua wood preservatives within proven high pressure (TANALITH™ E) and low pressure (VACSOL™ Aqua) impregnation processes.


The High Pressure Treatment Process

Find out more about a typical high pressure treatment:




The resulting TANALISED™ timbers and VACSOL™ Aqua treated timbers can be used with real confidence in a wide range of end uses and timbers are treated to suit the relevant Use Classes shown below.


TANALISED™ timbers can be used throughout Use Classes 1-4. VACSOL™ Aqua treated timbers can be used for Use Classes 1, 2 and 3 coated. For Use Class 3 coated an appropriate and well maintained surface coating must be used on the VACSOL™ Aqua treated timbers to maintain the integrity of the preservative protection.

Use Classes

The eventual end use of preservative treated timber is classified into one of the five main categories shown in the table below. These Use Classes, defined in BS EN 335-1, are based on the potential threat to the timber from decay or insect attack in its eventual application.


For instance, internal building timbers in Classes 1 and 2 will be under less threat than timbers used externally in ground contact – Use Class 4. Therefore, Use Class 4 timbers will require a higher degree of protection. Next generation TANALISED™ pressure treated timber can be used with total confidence in Use Classes 1 – 4.


Always ask your supplier which Use Class the timber is treated to, particularly for ground contact applications.

Use Classes – BS EN 335-1


  • UC 1 – Internal, dry (eg. Upper floor joists)
  • UC 2 – Internal, risk of wetting (eg. Tile battens)
  • UC 3 coated – Outdoors, coated, above ground (eg. Soffits/Cladding)
  • UC 3 uncoated – Outdoors, uncoated, above ground (eg. Cladding/Fence rails)
  • UC 4 – Direct soil or fresh water contact (eg. Fence posts)

Fire Retardant Treatments – DRICON™ & Sentrin FRX Exterior

Arnold Laver can offer a choice of tried, tested and proven fire retardant treatments for timber and board products wherever a fire protection is required by Building Regulations.

DRICON™ is a Wood Protection Association (WPA) approved humidity resistant treatment that is suitable for interior timbers and board products and exterior timbers that will have a weather protecting coating applied. DRICON™ is the only BBA certified fire retardant treatment for timber.


Sentrin FRX fire retardant treated timber has been pressure impregnated with a leach resistant (Type LR), exterior grade fire retardant formulation. It has been processed under ISO9001 controlled factory conditions to provide confidence in performance and long lasting protection without further maintenance, even in fully weather exposed situations.


Both treatments can be supplied to meet either Euroclass B or Euroclass C ratings in accordance with BS EN 13501-1 within the Construction Products Directive.


Both treatments are carried out in ISO 9001 Quality and ISO 14001 Environmental accredited facilities.



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