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When to use low pressure timber treatment

You might know that your timber should be pressure treated to protect it from deterioration, but do you know when to opt for low pressure treatment? And do you actually know what the term means? Let us help if we may.

Defining low pressure timber treatment

If you are looking to use your timber indoors, you may well be considering low pressure timber treatment. The term defines a water based treatment that pushes preservative chemicals into the timber, to protect it against insects and wood destroying fungi. This process is generally used on construction grade timber that is to be used for CLS framing, joinery, floors and ceilings. All of these applications are indoors and so no external, environmental factors are at play.

Key advantages

Low pressure timber treatment such as TreatWright LP (the WJ Group brand of treatment) enjoys a low uptake of water, allowing the timber to return to its optimum dimensions and moisture content more swiftly after treatment. The resulting colour is very natural (compared to high pressure timber treatment) – initially identified by a yellow tracer dye to aid identification, fading after 6-8 weeks.

Know your Use Class

The industry Use Class system can also help you to know when you should specify low pressure timber treatment. Ranging from 1 to 4, each level is determined by a specific type of application for the timber and we would recommend low pressure treatment for timber if Use Class 1 or 2 was an accurate reflection of end use:

Use Class 1

Suitable for internal timbers that will remain dry. For example upper floor joists and truss rafters

Use Class 2

Suitable for internal timbers that are exposed to a slight risk of wetting. For example tile battens and CLS framing

Higher Use Classes are suitable for external timbers only. In these applications, low pressure treatment of timber would not be appropriate to protect it sufficiently for a suitable length of time.

Happy to help

Should you have any specific queries about the treatment of timber; whether low pressure, high pressure or fire retardant, we’d be happy to help and advise you. Please just get in touch by calling 01482 338950 or emailing .(JavaScript must be enabled to view this email address)


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