Contemporary aluminium windows on a residential project

COR 70 Hidden Sash

Looks almost fixed. Opens when you need it.

A thermally broken aluminium window system designed around visual simplicity, with a slim 66 mm sightline and hidden-sash detailing that reduces the appearance of the opening elements.

Ask about COR 70 Explore the system

Sightline 66 mm

Frame / sash 70 mm

Glazing 26–40 mm

Maximum sash 160 kg

Hidden sash design

Keep the window quieter than the architecture.

COR 70 Hidden Sash is designed to reduce the visual distinction between fixed and opening glazing, keeping the elevation cleaner when the window is closed.

COR style aluminium hidden sash window in tilt position

Opening when required The hidden-sash appearance can still be combined with practical opening configurations including tilt & turn.

Reduce visual clutter

Less hardware competing for attention.

The system is designed around concealing or reducing the visual impact of components that would normally make an opening sash more obvious from the front.

Hidden sash appearance

The opening element is designed to read much more like fixed glazing when viewed from the front.

Concealed hinges

Compatible concealed hardware helps preserve cleaner aluminium lines around the sash.

ARCH invisible handle

The system can incorporate the discreet handle solution shown within the COR hidden-sash range.

Concealed drainage

COR 70 offers a drainage solution designed to reduce the visual impact of conventional face drainage.

The idea Make an opening window look as calm as a fixed pane.

That makes COR 70 particularly useful on elevations where window proportions, glass and surrounding architecture should remain the dominant visual elements.

ARCH Invisible Handle

Even the handle is designed to disappear.

COR 70 Hidden Sash can incorporate a handle integrated directly within the sash, reducing the visual impact of conventional window hardware when viewed from the front.

ARCH invisible handle integrated within COR 70 Hidden Sash aluminium window

Integrated within the sash Rotate to operate, then return the handle into the profile for a cleaner frontal appearance.

Hardware without the clutter

The handle becomes part of the window.

Rather than placing a conventional handle permanently across the face of the sash, the ARCH Invisible Handle is integrated into the profile itself.

Integrated into the sash

The handle sits within the sash rather than projecting permanently from the face of the window.

Cleaner frontal view

Returned into position, the handle becomes far less visually prominent when looking directly at the window.

Concealed hinges

The handle is intended to work alongside concealed hinges for a more consistently minimal appearance.

Built for Hidden Sash

The ARCH Invisible Handle is compatible with COR 70 Hidden Sash and COR 80 Hidden Sash systems.

System capability

Minimal appearance does not mean minimal capability.

Behind the hidden-sash aesthetic is a 70 mm thermally broken aluminium platform capable of substantial glazing, sash sizes and hardware loads.

Thermal performance Uw from 0.9

The Virtus brochure U-value chart lists COR 70 Hidden Sash from 0.9 W/m²K.

Standard sash 1300 × 2400 mm

Maximum stated dimensions for the standard solution.

HD side hung 1200 × 3500 mm

Maximum stated dimensions with the heavy-duty side-hung hardware configuration.

Maximum sash 160 kg

Final maximum size and weight depend on the selected typology.

System specification The frame stays visually restrained while the engineering sits behind it.

Sightline 66 mm

Frame / sash 70 mm

Polyamide strip 35 mm

Profile thickness 1.9 mm

Glazing 26–40 mm

Construction Thermally broken

Project fit

Best where clean window lines matter.

COR 70 is particularly suited to projects where opening windows are necessary but the elevation should still feel composed, minimal and consistent.

Contemporary homes

Useful where restrained aluminium detailing forms part of the wider architectural language.

Large glazed elevations

Hidden-sash windows can sit more quietly alongside fixed panes within larger window compositions.

Bedrooms & living spaces

Tilt & turn or side-hung operation provides practical ventilation without abandoning the cleaner aesthetic.

New build & renovation

The 70 mm platform can be incorporated into a broad range of residential window specifications.

Maximum sash dimensions and weights depend on the final configuration. Glazing, hardware, opening style and performance requirements should be confirmed against the individual project.