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Extruded Aluminum
. . . NOT aluminum clad

There are a lot of wood windows that take advantage of the durability of aluminum by using it to clad the exterior of their basically “wood” window.

Because the OpenUp® windows have a hybrid framing system that uses extruded aluminum on the outside and Accoya® wood on the inside, they sometimes get wrongly classified as just another “aluminum clad” window.  Nothing could be farther from the truth.

A Google search of clad windows returned this definition, “aluminum clad windows are wood windows or doors with a protective exterior layer of aluminum ‘wrapped’ around the sash and frame.” This layer is generally a very thin single layer of aluminum, often as thin as 1/32″.  The window is structurally still a wood window and the aluminum is just a protective layer to help prevent wood decay and paint failure.

Another issue with cladding is that the extrusion is open between the aluminum and the wood.  This area can collect moisture from both leakage and condensation.  This moisture leads to deterioriation of the wood and rotting in many cases.

When compared with one of the best aluminum “clad” wood windows the strength of the aluminum material of the OpenUp® windows was found to be over 30 times stronger in the windload resistance (horizontal) direction.

Why Accoya®?

bridge constructed with Accoya wood
modern home with Accoya wood cladding

The world’s leading high tech wood is Accoya®, and it makes aluminum doors and windows super insulated.

At 2Fold® our goal is to create the strongest products with the very best views. Consequently, our frames are the thinnest available. We combine the strength of aluminum with the unparalleled performance of Accoya® wood. This is what makes our products the best insulating.

Accoya® is PEFC and FSC certified and 100% non-toxic. Scientists have tested it thoroughly for dimensional stability, durability, and paint retention. Also, it is more reliable than even the best tropical hardwoods.

In fact, Accoya® is a benchmark in the industry because it is so reliable. Accoya® is replacing scarce hardwoods for green-friendly buildings.


Many companies are more environmentally conscious than they once were. As a result, they are looking for more sustainable options when it comes to high tech wood. Accoya® grows very fast. It grows in responsibly managed forests. So, scarce tropical hardwoods, treated woods, and less sustainable materials are replaced with Accoya®.