Tunnicliffe Timber specialise in treated timber profiles especially for the Joinery Industry. They produce untreated, chemical preservative treated and thermally modified timber products. Tunnicliffe's wood treatments include Tunnicliffe Thermally Modifed Timber (TMT) and Tanalith® Ecowood (TanE) chemical treatment options.
The addition or Accoya and Finger Jointed/ Laminated Taun as species options come with the agreement with ITI Timspec.
Tan®E
Tunncliffe Timber uses Tanalith® Ecowood (TanE) for it is chemical preservative treated joinery products which meets Hazard Classification H3.2 (above ground) according to NZS 3640:2003. This product is part of Lonza's Tanalith® preservative product family, which is a range of metal-based water borne preservatives for demanding outdoor, agricultural, and utility wood products. The family of Tanalith preservatives provide robust protection against decay and insects in most outdoor situations. Read more here
TMT Thermally Modified Timber
Thermally Modified Timber (TMT) is a durable timber product, free of any chemical. The timber used is thermally modified NZ Radiata pine, which when thermally modified, is comparable with naturally durable timbers such as Cypress Macrocarpa, Western Red Cedar and Redwood. Apart from increased durability properties, the other main feature is added stability due to the reduction of equilibrium moisture content (EMC). TMT Radiata pine will display approximate half the amount of dimensional change when compared with non-modified Radiata pine under the same conditions.
The technology can be seen as revolutionary for our New Zealand Radiata pine resource as the timber will be able to enter areas of application which were previously the domain of imported timbers.
Tunnicliffe's TMT is a truly sustainable and environmentally friendly, long lasting product of the future for New Zealand and beyond.
The Process
New Zealand grown Radiata pine is very suitable for the heat treatment process. The timber is modified in a special chamber where it is exposed to temperatures over 200 degrees Celsius in a computer-controlled process. Steam is added to prevent the timber from combusting but also influences the chemical changes taking place in the timber.
The process permanently changes the chemical and physical properties of the timber. In other words, the wood structure is re-formed or “modified”. These changes are mainly caused by thermal degrading of hemicelluloses (a sugar compound in the timber). It increases the biological durability, stability and the thermal insulation properties.
Durability
In principle the durability is increased since the edibles (sugar compounds), on which fungi live on, have been taken out by burning-off. But there are several other changes occurring during the modification process that also contribute to the increased durability such as a lower level of moisture.
To date, in accelerated above-ground tests TMT is more durable than H3.1 treated radiata pine and macrocarpa heartwood but not as durable as H3.2 treated Radiata pine. Macrocarpa heartwood and H3.1 treated timber are included in Table 2A sections 2A1-2A3 for weatherboards, fascia, barge and coverboards, plus 2A5-6 for exterior joinery and timber reveals for aluminium windows under NZS 3602:2003 “Timber and Wood based Products for Use in Building” section 111 “Requirements for wood-based building components with a 15-year durability”. Therefore, Tunnicliffe TMT should be an acceptable substitute in low-moderate decay hazard situations.
Dimensional Stability
The equilibrium moisture content (EMC) is reduced, which increases the dimensional stability of the timber as there is less swelling and shrinkage caused by moisture uptake / release.
Appearance
The timber darkens, right through, towards an attractive chocolate brown colour. The higher the maximum temperature treated to, the darker the timber looks.
Modification Level
The level of modification depends on the end-use application. The three factors to be considered are durability, stability, and strength. The modification process is not suitable for structural timber such as framing, beams and trusses. A compromise is needed between maximum durability and strength.
(Displays Moulding options)