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Case Study – French Doors & Windows

Aluminium is an excellent replacement for traditional steel french doors and windows.

The brief

Our customer had built a new garage extension and came to us because they wanted a specific look. They wanted slimline aluminium for a steel look but without the steel door price tag! They also wanted improved thermal values and less maintenance. The customer had employed an architect so we could use the architectural plans to work out the size of the apertures. We were supplied with the building plans for the property.

We visited the property before any work started, so that we could ensure what we were supplying would deliver the look and feel the customer was aiming for. It was important that we blended the look in with the rest of the property, as this was a single-storey extension and they can sometimes look out of place.

Our approach

We met on site with our clients to discuss their plans.

We advised the customers to choose black aluminium frames with bespoke nickel chrome Art Deco handles (also available in brass). The extension was built with two openings ready for our doors to be fitted and they look fantastic!

Product focus

The minimalist Alitherm Heritage range in aluminium was perfect for this project. The thermal values of aluminium are much better than steel and also require less maintenance as well as being around half the price. Our range of ultra-slim aluminium French doors give the same look of traditional steel French doors.

heritage aluminium french doors windows HD

The result

The result is an extension to the existing property that looks like it was always part of the house. The customer has achieved their desired look and has created the space they wanted. Everything blends together perfectly and the husband even has his own snooker room.





The Smart Alitherm installation is a standard residential casement-style system designed to replace old, draughty, poorly insulated windows. This is also great for new build projects where slim sightlines, minimal maintenance, and low U values, to comply with modern building regulations, are essential.


The amazing features of these products include:

  • Available in 20 colours at no extra cost— subject to quantity ordered
  • Polyester power-coated, making them virtually maintenance-free
  • Can be fitted into original timber sub-frames or directly to brick or stone
  • 200 RAL alternative colours available at a minimal surcharge
  • A range of bespoke ironmongery available
  • A range of external aluminium or hardwood cills


Our range of ultra-slim aluminium French doors are perfect for replicating the Art Deco style, while also lending themselves to a more contemporary style. Manufactured in the UK, using the highest quality materials, our aluminium French doors comprise of double polyamide thermal break sections which dramatically minimise any chance of condensation. Aluminium French doors and windows offer an excellent and cost-effective alternative for replacing draughty, old steel windows. We use slim sightlines and thermal break technology as well as the latest Low-E Planitherm double-glazed units, which are argon gas-filled, and include Swiss warm-edge spacers for added insulation.

Our Google Reviews

  • Delighted with the new windows that we just had fitted. They are top quality and look amazing. They were very professionally fitted, with great attention to detail. I thoroughly recommend them.

    Scott MacDonald Avatar Scott MacDonald
    November 27, 2020
  • We recently had a new front door and windows fitted. Very efficient service from start to finish with everyone extremely helpful. The fitter was very careful especially bearing in mind it was raining on the day of fitting. Would definitely recommend.

    Chris Shortman Avatar Chris Shortman
    February 23, 2021
  • One year ago we had our windows and doors installed. We are very happy with the product so far. What made me write a review one year later is their amazing customer service. Our door needed adjustment and I asked someone to look at it and fix it. They send an engineer the next day, who came on time and managed to fix it. Very pleased. As it is quite rare these days, companies cut corners and dont look after their clients.

    Lucy Niz Avatar Lucy Niz
    October 4, 2020
  • The Window Sanctuary supplied and installed a window in the current house we are restoring. We were extremely happy with the service and quality of the window. Would definitely recommend this company for your period windows.

    sheldon partridge Avatar sheldon partridge
    August 20, 2021
  • The team at The Window Sanctuary have been a delight to work with. They have given us really personal customer service, ensuring that every final detail works for us and our build and have listened to what is important to us (happy to be flex when we change our minds!). Quick to respond and offering a really consultative approach, alongside good value for high quality products, I would strongly recommend their service. I was really specific in what I wanted for bifold doors, wanting time achieve that much coveted Crittall appearance and they’ve made this work for us with a good quality option that doesn’t break the bank. What a find!

    Abigail Barclay Avatar Abigail Barclay
    January 20, 2021