top of page



At ThermaDura we only use laminated timber for our joinery. There are many advantages for the use of laminated timber for the manufacture of windows, doors and conservatories.


  • Laminated timber does not warp and twist and does not tend to crack

  • Laminated timber is structurally stronger than solid timber

  • It is a sustainable way to achieve the highest timber quality


For our windows and doors we use quarter or semi-quarter sawn timber. The timber is free of knots and defects and the moisture content is 10-12%.  This reduces movement in the timber and is another quality aspect of our joinery. The glue used in between the laminates is D4 exterior glue (marine grade).



All timber species we offer are durable by nature and are characterized with a high density. In other words we only use hard timbers for the structural part of our conservatories. The advantage of using high density timber is that it is resistant to mechanical wear and tear and that applied coatings last longer. The hardness of the timber also makes it more difficult  for organisms to penetrate the timber.

After squaring the timber we machine the faces in a state of the art hydro-planer which replaces the traditional sanding. This way we achieve a maximum durability of the applied water based finish.


Oak ThermaDura website.png
Larch ThermaDura website.png
Spruce ThermaDura website.png
EcoDura Thermadura website.png
Abodo ThermaDura website.png

Siberian Larch


American Oak



DesignLine only

ecoDura light

DesignLine only


DesignLine only

Siberian Larch


Siberian Larch grows in Siberia, Europe and North America (Canadian Larch). Larch is very rot resistance, and so it is especially valuable for weatherboards, decking, posts, poles, railroad sleepers, and mine props. The harsh climate of Siberia and north Canada results in a very hard and durable timber. The high density of the Siberian Larch of 0.64 g/cm3 is proof of this. The high density and tannin content make it difficult for the organisms that cause decay to penetrate our wood. Siberian Larch is durable without additional chemical treatment. Siberian Larch is the perfect timber for windows, doors and conservatories.

All our Siberian Larch scantlings are sustainable and FSC - certified.

Please click here to show a Siberian Larch project


At ThermaDura we offer to manufacture our conservatories, windows and doors in American Oak. This historically important timber is classified as class two durable (BS EN 350-2). Oak wood has a density of about 0.75 g/cm3. It is known for its great strength and hardness, and is very resistant to insect and fungal attack because of its high tannin content. It also has very pleasing grain markings, particularly when quarter sawn. American Oak is durable without chemical treatment. Oak is also a great timber for conservatories.

Please click here to show an American Oak project

Oak windows
Ecodura rgb.jpg

EcoDura is Thermowood at its best. Grown right here in New Zealand it is a beautiful timber for windows and doors. The colour of the timber is a light to medium brown.

TMT is thermally modified timber in it’s purest form and is perfect for any project where environmental responsibility is paramount.

The product is carefully and meticulously heated to high temperatures through state of the art computer controlled equipment. With just the application of heat and steam, the timber is modified at a celular level to create a naturally durable and beautiful timber.

Vulcan Screening image_edited_edited.png
Abodo_Brandmark_Horizontal_RGB (Earth).jpg

Abodo Vulcan is created from thermally modified New Zealand plantation timber and engineered with a vertical grain construction for superior weathering characteristics. The thermal modification process combined with lamination means Vulcan has enhanced stability, reduced resin content, is a beautiful homogenous brown colour, and is naturally durable so does not require any chemical preservatives. Abodo is FSC certified.

ThermaDura offers ABODO for the DesignLine timber- aluminium window and door range. The colour of the timber is a dark brown.

Please click here to show an ABODO project



ThermaDura offers European Spruce for the DesignLine Timber-Aluminium window and door range. Spruce is a light coloured timber with a low density which is used mainly for our PASSIVHAUS certified DesignLine 90 window range due to the good thermal properties.


Exterior joinery is exposed to harsh elements most of the time. Heavy rain, hail, and extreme heat conditions are common in New Zealand. When exteriors are exposed over time the difference between any old window and a quality window becomes apparent. Fairy tales are told:  people say that  “Timber windows are not suitable for the harsh climate in Central Otago” - we disagree.


Timber is a natural material unlike PVC and Aluminium. Timber windows and doors stay dimensionally stable in order to fulfil their task. We have benefitted from centuries of European design and skill in engineering joinery; we use that knowledge wisely. Unfortunately in our fast modern times the need to take the special characteristics of timber into account is often replaced by time saving work processes. At ThermaDura we are joiners with a passion for timber and we stick to the traditional skills without cutting corners.

Here are some key characteristics of quality windows and doors:


  • Solid triple tenon mortise and tenon corner joints

  • D4 marine glue used for laminations

  • 4 layer laminated timber for dimensional stability

  • The use of kiln dried timber (slow drying process), MC10-12%

  • Defect free timber

  • The use of semi quarter sawn or quarter sawn timber

Comparison ecoDura Abodo.jpg



Colour comparison TMT NZ Radiata Pine

bottom of page