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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

  • Great customer service. Good quality product. We needed a door adjustment and they have sent someone the next day.

    Lucy NNN Avatar Lucy NNN
    March 3, 2021
  • Really enjoyed dealing with the Window Sanctuary. The office team are very friendly and courteous and the installation team were good fun and very thorough. The finishing touches were beyond my expectations. We're delighted with our new windows and the enhanced view they provide.

    Tim Glynne-Jones Avatar Tim Glynne-Jones
    March 9, 2022
  • 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
  • We had a few quotes for 2 x black aluminium windows and French aluminium doors with fixed side panels. The Window Sanctuary were the most competitively priced and were quick to respond to our quote request and follow up questions. The timeline they gave for delivery and installation was accurate and the installers did a great job. We are really happy with our high quality and stylish looking doors and windows! Makes such a difference to our house.

    Anna Clarke Avatar Anna Clarke
    September 30, 2022
  • The team did a great job installing new sash windows in our flat: the wood grain effect on their PVC looks great, they took away our old windows and worked swiftly, on time and on budget to get the new ones fitted. I can definitely recommend them! Thanks!

    Claire C Avatar Claire C
    February 24, 2020