Emplas | The window and door fabricator of choice

Aluminium Casement Window

A minimalistic and contemporary edge. The ALuk Optio 58bw ST steel replacement aluminium casement window.

The perfect aluminium casement window

Originally designed as a replacement for period steel-type windows, the AluK Optio 58BW ST steel replacement aluminium casement window offers an ultra-slim 46mm sash, creating a minimal sightline.

Despite its origin as a heritage replacement, this minimalist offer can also be designed to create a contemporary aesthetic, while maximising the glazed area.

We’re able to combine this with the ultimate in thermal performance achieving u-values of as low as 1.4W/m2 double-glazed.

AlUK Logo

Choose from three different options:

from Emplas are available in a choice of chamfered, sculptured or flush casement options.


A more ornate design replicating period steel window installations


A simple design with an angled fall away from the glass line


A cleaner and contemporary design, creating a minimalist contemporary appearance

Why choose the AluK Optio 58BW ST

Durable colour

Our aluminium window and door ranges use a special flash-anodising process.

Completed ahead of powder coating this creates a protective anodised layer of aluminium oxide providing a better substrate for powder coating but also preventing filiform corrosion.

It means that our window and door range is supplied in a marine grade finish as standard and guaranteed for 10-years. 

Standard Colour Options

Our standard colour ranges include a choice of white, anthracite grey, chocolate brown and deep black, plus dual colour anthracite grey-on-white and deep black-on-white. 

Special Colour Options

We can also offer you access to a range of textured finish options and supply any RAL colour on special order, giving your customers the flexibility to pick out the perfect shade to compliment their property.

24/7 online ordering

Want to find out more about our energy efficient window and door ranges?

AluK door and window manufacture and supply

We also supply the AluK F82 Luminia aluminium bi-folding door and the AluK BSC94 aluminium sliding patio door, plus a complete range of AluK aluminium windows.

Looking for a Lantern Roof supplier?

We’re a single source of supply for your glazed or flat roof extension with a range of bi-folding, sliding and French doors and windows.

Lantern Roofs

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