Traditional style

Designed to complement traditional British architecture, look no further than FORMA and FORMAPLUS. Beautifully styled, these designs bring the classic into the current day to create a finished look that’s simply transformational. It’s sheer sophistication, reimagined.

Both options work to bring a softer line to your windows, helping your project to blend more seamlessly into its surroundings. Available with or without glazing bars which particularly suits this style of windows.


Classic profile on the inside

Classic style glazing bars

Classic angled glazing bead

Rationel FORMA

This timber window range comes with angled glazing bead and ovolo moulded profile making it an ideal choice for country-style and traditional designs. With an extensive range of colour choices available, you’re sure to find one you’ll love.

Triple glazed

– Best performance: 0.78 W/m2 K U-value
– 42 dB Rw sound reduction

Double glazed

– Best performance: 1.27 W/m2 K U-value
– 40 dB Rw sound reduction

Key features

– Timber frame
– Minimum 40-year life expectancy
– Over 200 colours available


Made from timber, with external aluminium cladding, Rationel FORMAPLUS offers all the benefits of natural wood on the inside and easy maintenance on the outside.

Triple glazed

– Best performance: 0.79 W/m2 K U-value
– 42 dB Rw sound reduction

Double glazed

– Best performance: 1.29 W/m2 K U-value
– 40 dB Rw sound reduction

Key features

Aluminium-clad timber frame
– Low-maintenance
– Minimum 40-year life expectancy
– Over 200 colours available, with no extra charge for dual colour*

*When choosing from our standard colour range

Timber or aluminium clad timber windows?


Our timber windows consist of solid wood from the very innermost structure through to the external, resulting in excellent thermal and acoustic performance, combined with easy maintenance. It is available in either double or triple glazing, and has been designed to exhibit the very best in energy efficiency.

Rationel FORMA is a timber product.

*Illustration of material only – this colour combination can not be purchased.

Aluminium clad timber

Boasting all the benefits of all-timber windows using the same solid timber structure, the external aluminium cladding offers exceptional durability on the outside, with easy maintenance on the inside. The addition of aluminium cladding means a far increased life expectancy of your windows – by as much as 20+ years. What’s more, the extremely durable nature of this style ensures it will withstand even the harshest of weather conditions with ease.

Rationel FORMAPLUS is an aluminium clad timber product.


Make a statement or play it cool with your choice of colour. Our standard colours suit most architectural styles, while our special range is ideal for highlighting unique features. Our windows and doors are available in one standard colour all over. AURAPLUS and FORMAPLUS windows can also be ordered with a different colour inside to outside, with no additional cost*.

*When choosing from our standard colour range

RAL 9010
Pure white

RAL 9001

RAL 9003
Signal white

RAL 9002
Grey white

RAL 7035
Light grey

RAL 7044
Silk grey

RAL 7038
Agate grey

RAL 9007
Grey aluminium

RAL 7030
Stone grey

RAL 7037
Dusty grey

RAL 7001
Silver grey

RAL 7015
Slate grey

RAL 7012
Bastalt grey

RAL 7016
Anthracite grey

RAL 7013
Brown grey

RAL 1035
Pearl beige

RAL 7032
Pebble grey

RAL 7006
Beige grey

RAL 7022
Umbra grey

RAL 6003
Olive green

RAL 6009
Fir green

RAL 8017

RAL 8019
Grey brown

RAL 7024
Graphire grey

RAL 9004
Signal black

RAL 7021
Black grey

RAL 8022
Black brown

RAL 9005
Jet black

Granite colours (aluminium clad timber only)

G01 White

G10 light grey

G20 Medium grey

G30 Warm grey

G60 Dark grey

G80 Black

Obscure panes

Rationel OBSCURE panes are designed to restrict the view into private areas such as bathrooms. As the translucent patterns are located on the inside of the panes, they can still be cleaned like traditional glazing.



Listral D



Small Cathedral


All windows and doors from Rationel are delivered with energy glass with a warm edge spacer, which reduces cold bridges and the occurrence of dew and condensation on the windows. The space between the panes of glass is also filled with the environmentally friendly argon gas, which provides significantly better insulation and reduces heat loss. The inner glass pane has a thin, transparent metal coating, which reflects the heat back to the room and ensures maximum light incidence.

Frosted or patterned glass

Designed to reduce transparency, Rationel OBSCURE glass is the ideal choice for any room where both privacy and natural light are essential, such as a bathroom.

Acoustic control

If you live in a big city, near a busy road, or close to any source of noise, Rationel SOUND glass offers great acoustic control, helping absorb sound and improve the comfort of your home.

Solar control

Designed to minimise solar gain – free heat from the sun – Rationel SOLAR glass is the ideal choice for south or west facing windows or facades, to help ensure a comfortable temperature in every room.

Security glass

Difficult to break, Rationel SECURE glass features laminated panes designed to deter even the most persistent burglar. Rationel SECURE glass has been tested in accordance with several national and European safety standards, including Secured by Design. For maximum performance, specify alongside the full range of Rationel security features.

Coloured glass

Choose from a wide range of Rationel FACADE standard colours (plus additional shades on request) to add visual impact and special effects, or to create coloured panels across floor slabs, for example.

Minimise the risk of accidents

Toughened or laminated – or a combination of the two – extra-strong Rationel SAFETY glass is designed to break safely in order to minimise risk of injury, and has been tested and marked according to several national and European standards.