High & Low Pressure Treatment

High and Low Pressure Treatment

Preserving the quality.

In order to preserve the end use of our timber, we have been at the forefront of preservative applications since 1976.

Preservative treatment is critical for ensuring timber has added durability and is suitable for its desired end use.

The technical standard BS8417 groups the uses, or applications, of timber into various ‘Use Classes’. These are as follows:

  • Use Class 2 – this covers timber for interior uses in a dry environment, above ground or DPC and covered. Examples include: Tiling battens, framing and roof timbers, internal joists and sole plates

  • Use Class 3 – this is for exterior applications above ground, with small letter ‘u’ indicating uncoated wood, and small letter ‘c’ indicating coated wood e.g. on a painted timber window. Examples include: Deck boards, cladding (including battens), fence rails and boards and fascias

  • Use Class 4 – this is for wood used on or in the ground and for external structural support, whether or not it sits on other materials like an under-deck weed-suppressing membrane. Examples include: Fencing, fence posts, agricultural timbers, retaining walls, playground equipment, deck posts, joists and sub structures

Timber Treatment Provided by JDT

All preservatives applied are developed and distributed by Osmose Timber Technologies and are all water-based solutions. 

Low Pressure Treatment

Accommodating up to approximately 38m3 of timber per individual preservation cycle, Tank number 1 applies Osmose Protim E415 a water based preservative which is used in a low pressure process; for use in construction projects that require protection and longevity e.g. roof timbers, timber framing, internal & external joinery and other internal & external timber projects, that are above dpc/ground level.  The type of treatment can be used for Use Class 2 & Use Class 3 timber.

High Pressure Treatment

Tank 2 holds approximately 20m3 of timber per individual preservation cycle, and applies Osmose Celcure AC500 water-based preservative which is used in a high pressure process; for use in timber above dpc and also in ground contact. The type of treatment can be used for Use Class 3 & Use Class 4 timber.

Both tanks and subsequent plants, are equipped with a software package; that ensures the correct amount of preservative is applied with vacuum and pressure processes accurately maintained throughout. We have also worked with Osmose to source a permethrin free treatment preservative. The resulting preservative B610 is applied in a low-pressure process within a small treatment vessel in our Elm Park site for all our permethrin free preservative requests.     

We also offer our customers an older style preservative Osmose Protim E415 which is also water based. 

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