Rationel FORMA and FORMAPLUS Traditional Windows

Designed to complement or enhance the numerous British house styles, Rationel FORMA and FORMAPLUS are a more classically styled option, yet meeting modern tastes and trends for window replacements.  Sophisticated design, softer frame lines and always creating beautiful new windows, with matching doors, of the highest performance and quality. Rationel FORMA and FORMAPLUS are characterised by their unique detailing whether you choose them as fully glazed or with beautiful glazing bars.

Rationel FORMA is an all-timber window design, best suited when you want and love the warm and natural feel of real wood.  FORMAPLUS provides an external aluminium cladding design, with exactly the same overall styling and options, benefitting from easy maintenance on the outside, and an even longer lifespan of up to 80 years. There’s no better performing window than timber or alu-timber, delivering excellent insulation, acoustics, interior comfort, and above all, timeless style.

Rationel FORMA and FORMAPLUS to a bungalow
  • Premium quality timber and alu-timber design
  • U-Values as low as 0.79Wm2K
  • Meets 2022 Building Regulations with suitable glass
  • Double or triple glazed
  • Luxurious window furniture
  • Long lifespan

Whether you choose all-timber or aluminium clad, both Rationel FORMA and FORMAPLUS are exceptional in their overall design. The finest materials create a solid window, with high-specification glass, and premium hardware designed for low-maintenance and minimal care.

Security, weather protection and interior comfort all come as standard in a choice of fixed, top, or side hung windows, with matching patio doors, front doors and balcony doors. Multipoint locking, security glazing, durable yet beautiful window hardware and clever design promise you luxurious timber or alu-timber windows that are a long-term investment in your home.

Available in a comprehensive choice of designs, frame colours, glass and accessories, Rationel FORMA and FORMAPLUS are professionally installed by us and come with a quality guarantee.

Rationel FORMA and FORMAPLUS are designed to be enjoyed for generations and built for the future.  Made with sustainably sourced timber and premium aluminium, they’re built to performance, energy efficiency and sustainability, whilst enhancing a property with visually appealing, warm and luxurious windows and doors.

Customise Your products

A personalised touch

Glass options

Contemporary designs that enhance security and privacy.

Integral Blinds

An attractive addition delivering privacy and shading when you need it.


Peace of mind starts when you get in touch and lasts for years.

steve arundellsteve arundell
13:43 02 Nov 23
Chris and Andy listen to what we wanted and their team then delivered in spades.Great company well worth the effort to contact.
ArBa InstallationsArBa Installations
22:23 20 Dec 22
Posting from the view of an Installations company, C & A have always been a pleasure to deal with. Their process is very thorough and products are top quality. We use them for all our commercial doors and would highly recommend all their products and them as a company.
Paul DillonPaul Dillon
14:17 23 Nov 22
Great service. Top products. Thank you. C&A
Alfie TonerAlfie Toner
13:43 21 Nov 22
Great company to deal withQuick quotesPleasant staffGreat productsGreat customer supportDefinitely recommend
22:50 12 Jun 22
Couldn’t recommend this amazing company enough from start to finish the professionalism have been second to none. The quality of the work undertaken shows how much C&A take pride in there work. Thank You again
Gary WoodhatchGary Woodhatch
11:11 11 Mar 22
Have been dealing with Andy and Kim in the main at C&A windows for a few months now and the service overall has been great, quick quotes, lead-times inline with expectations and well presented and packaged goods. Great responsive aftersales assistance when called upon. Would recommend C&A for sure.
richard newellrichard newell
07:44 11 Mar 22
Always a pleasure to work with the people at c and a, very good communication throughout the process and most importantly the product is excellent.Highly recommended.

Send us an email

Send us an email if you have any questions.


call us

Need to know more about our products? Call us, and a member of our sales team will help you.

01787 477976

visit us

Book an appointment to visit our showroom.  
8am – 5pm Monday – Friday

Unit 1, Lancaster Way
Earls Colne Business Park, Earls Colne, Colchester CO6 2NS

We are looking for new staff to join our team.