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S Series Sliding Sash Window
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Vrogum Solborg Airtight Sliding Sash Window

Our Danish Solborg sliding sash window is an innovative airtight sliding sash window (class 4 airtightness) with “tilt to clean” function allowing the lower sash to be cleaned from the insider of the room. This custom-made window combines Scandinavian design and quality with timeless and traditional regency looks and have been installed in many properties in conservation zones and Spa towns.

Slow-grown pine from Northern Scandinavia is the main material – all from sustainable forestry and a high-percentage of heartwood. A three-stage finishing process of primer, base coat and (most importantly) water-based final paint application ensures that the timber can breathe freely and avoid moisture being trapped within. The paint used on this product is also non oil-based therefore does not yellow or oxidise like traditional paints often used in joinery.

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Full Details

Traditionally, sliding sash windows have characteristically low energy efficiency, which deteriorates with age. Vrogum’s Solborg, however, changes this. Featuring ground-breaking hardware, the Solborg has some of the best water and air-tightness on the market – just as effective as a casement window. By using super low argon gas as standard, our double glazed sliding sash window has a U value of 1.2 W/m^2k and 39 dB sound reduction – meeting low energy requirements for 2020.

This patented airtight sliding sash window is often selected to significantly upgrade the energy efficiency of houses with traditional box sash windows. The unique lever mechanism on each sash pushes the whole sliding sash against a compression rubber seal and does not rely on brush seals (these are common in most sliding sashes and very quickly lose stated airtightness with use).

Upon opening the window, the sashes are separated away from each other – thus avoiding wear on the weather strip. On closing, the sash presses against the weather strip, creating a tight seal.

Designed to be hassle-free to operate: the bottom sash can be tilted inwards, allowing for easy and safe window cleaning. In addition, trickle vents and a lockable handle on the lower frame are configuration options.

The high density of the slow-grown Nordic pine provides the Solborg with a high durability class. And the application of microporous water-based paints further improves the durability. The paint allows the timber substrate to breathe freely and minimises the chance of paint bubbling over time.

Both spring-balanced sashes use a multi-point locking system, have the option of a key-lockable handle and glass units are inserted from the inside. So, security-wise, this is far above what you would expect from a traditional sliding sash. You can also utilise a secure “night-vent” open position where the window can be locked open, leaving a 20mm gap.

The product uniquely delivers airtightness, energy efficiency and a timber window with a long life expectancy. As with all timber windows, these do require periodic inspection and maintenance.

If you need to maintain the traditional look of a property by using sliding sash windows, but don’t want to lose the vastly better airtightness of a casement, give us a call on 01608 684 607 to ask for your free, no obligation quotation.

MaintenanceLow maintenance
Best Ug-Value1.2 W/m^2k
Finishes Any RAL Colour
GlazingDouble glazing,
Frosted, Super Low E, Security, Sun and noise protecting
Click here for more information
Performance and
Airtightness to class 4 standards at 600 Pa
Watertightness to class 8A standards
Wind Load to class C3 standards
Maximum SizesWidth: 1498mm Height: 2998mm
for single sliding sash window
Manufactured inDenmark
Opening Configurations


Sliding Sash Configuration


RAL Colour options in the standard range for Vrogum Solbourg

RAL3003 – Ruby red

RAL6005 – Moss green

RAL5009 – Azure blue

RAL5024 – Pastel blue

RAL7040 – Window grey

RAL1013 – Oyster white

Where you see a next to a colour, clicking on it will take you to a page of our client galleries that use that RAL Colour.
Some colours are subject to additional lead time from Vrogum.
Colours shown should not be used in place of an official RAL colour sample. We cannot guarantee colour-accuracy when viewed on-screen or printed out.

Profile Drawings