Why "normal" timber windows & doors don't last

Unfortunately "normal" Australian timber windows are made from low durability timbers such as common hardwoods and Western Red Cedar. They rely on the paint coating for durability.

We only use the highest performing Class 1 durable (the highest grade) timbers to give the best long term performance; timber windows and doors that don't rot.


Why coatings on "normal" timber windows & doors don't last

Unfortunately "normal" Australian timber windows are made with tight "joints", so coatings cannot penetrate. With weathering, these joints trap water and distort, then the coating cracks and eventually the window or door fails.

Site painting also misses a lot of the nooks and crannies of the window joinery, so leaves the timber unprotected.

We produce all joinery with rounded joints to ensure they are draining. 

All our windows and doors are fully spray painted or stained in our workshop before glazing, to ensure that the joinery is completely protected. We paint with 4 coats - sealer primer, undercoat and two topcoats.


Why "normal" windows & doors don't seal

A "normal" Australian window typically has only one point of locking, so any distortions in the sash/frame allow leakage.

Many Australian standard windows rely on brush seals, which have no compression sealing capability.

The result is poor acoustic performance with excessive air infiltration.

That's OK when the window or door is open, but not when you want it closed!

We only use the highest performing segmented compression seals  to give the best performance.

We only use mulitpoint locking systems for enhanced security and performance.


Why "normal" double glazing doesn't work

A typical single glazed window has a U-value of 6.5 W/m2K; which is an R-value 0.15 m2K/W.

A "normal" Australian double glazed unit is two pieces of glass with a 6 - 12 mm air gap.

A "normal" Australian double glazed window has a U-value of 3.5 W/m2K; which is an R-value of 0.3 m2K/W.

Now lets look at a "normal" Australian building and the typical heat losses and gains:


Building Heat FlowsSource: SEAV

Typical R-values in Australian buildings:

Roof: R-value of 4 m2K/W

Walls: R-value of 2 m2K/W

Floor: R-value of 1 m2K/W

Easy to see that all the energy - goes right in/out the windows & doors!

So given all the heat losses through windows in Winter, we should target:

Windows: R-value of say 1 m2K/W; so that's a U-value of 1 W/m2K.

In Summer we clearly need to significantly reduce the heat gain, so we need high performance insulated glass units with low-emissivity coatings (high in reflectivity), ideally on two or more surfaces; with low Solar Heat Gain Coefficient (SHGC).

We only use the highest performing low-e double and triple glazed insulated glass units to give the best performance. Insulated glass units are a minimum of 24mm deep for double glazed; 36mm for triple glazed to 44mm.

As every orientation of a building is different, we specify different glass to optimise the performance.