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1. Is the timber you use for the windows and doors treated with chemicals?

A: No, we only use naturally durable timber species like Siberian Larch, ecoDura, Abodo or American Oak. The high tannin content makes the timber durable. ecoDura timber is naturally treated.


2. Why are timber windows and doors beneficial for a healthy room climate?

A: Wood is hygroscopic. This means timber can absorb  moisture in a situation of high humidity in a dwelling and it can also give this moisture back when the inside climate is dry. This is called 'timber breathes". At ThermaDura we only use waterbased finish products that allow the timber to breathe to contribute to a healthy room climate. We do not use Polyurethane finishes for this reason. 


3. Do you offer Passive House windows and doors?

A: We offer timber and timber- aluminium windows and doors with triple glazing up to 65mm thickness, suitable for passive houses. Due to our efficient production process we can produce this extremely efficient joinery at a competitive price right here in Mosgiel, New Zealand.


4. Are your timber and doors suitable for the harsh weather conditions in Central Otago?

A: All our timber is multilayer laminated to reduce movement in the timber to the absolute minimum. Also, all the timber we use is kiln dried so the moisture content is well adapted to the dry climate in regions like Central Otago. Our wooden windows and doors are 3d adjustable with an allen key. ThermaDura windows  and doors are made for extreme temperature and humidity changes in a small timeframe - perfect for Central Otago conditions.


5. Why are European style windows and doors more chunky than ordinary sash windows?

A: There are multiple reasons for this, but a major reason is to prevent any warping and twisting of the joinery and for increased thermal efficiency. The outside of the timber window frame is affected by the climate on the outside and the inside of the window frame by the humidity on the inside. As on the inside a house is warm an dry and from the outside it can be wet and the moisture content can be high at times, it is important to have a timber core in the middle that is not affected by temporary climate changes. To have an unaffected core, the thickness of the timber frame needs to be increased.

At ThermaDura we use 78mm, 90mm and 102mm window and door frames compared to the 40mm thickness  of ordinary NZ style timber windows and doors.

6. I like the natural look of timber and do not want to use a woodstain on my windows and doors. Do you have a solution for me?

A: The difference between e.g. a weatherboard and a window is the function. A weatherboard has no technical function and for this reason a bit of movement is not as important. With wooden windows and doors this is a different story. The windows and doors in a dwelling need to function for many years to come and for this the European regulations are very strict on which product is certified to be used for exterior joinery.

As we are the specialists we see it as our duty to customers to ensure they have a lot of joy with their wooden windows and doors. For this we adhere to the strict European standard and use only approved products.


For a natural clear option on the outside and inside we use a product which has proven its durability in New Zealand conditions: The Adler Ligno+ system.


At the moment there is no clear framework in New Zealand which which specifies the products that can be used for timber windows and doors. At ThermaDura we voluntarily adhere to the German standard which defines clearly which finish products is tested to be used for wooden windows and doors.


7. I do not like the Aluminium extrusion at the bottom of the tilt & turn windows. Is there another option?

A: Yes, we can use a timber bead instead of the Aluminium extrusion. There is a shorter maintenance intervall with a timber bead.


8. Are your wooden windows and doors thermally broken?

A: Timber acts as a thermal break and this makes timber the most suitable material for windows an doors. The frame of an Aluminium window with a thermal break is not as efficient as the frame of a timber window. Compare the U-values of the different manufacturers.


9. Do you use treated timber?

A: At ThermaDura we do not use chemically treated timber as we prefer to use naturally durable timber for ecological and health reasons.


10. European-style windows normally opens inwards. Do you also build outward opening doors?

A: we manufacture outward opening single doors, French doors and bifold doors in our NatureLine- range. 


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