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Best Aluminium Bifold Doors for a Home Extension

Best Aluminium Bifold Doors for a Home Extension

Buying GuidePublished 16 June 2026By BDF Architectural

A rear extension and a set of bifold doors go hand in hand — the doors are what turn a new room into a bright, open space that connects to the garden. But a few decisions made early will determine how well they perform and look for years. Here is what to think about when choosing bifold doors for an extension.

Size and panel count

Most rear extensions suit a three or four panel bifold, opening up roughly 2.4m to 3.2m of wall. Decide early whether you want a traffic door — a single panel you can use day to day without folding the whole set back — as this affects the configuration and should be designed in from the start.

Glazing and thermal performance

For an extension you will spend a lot of time in, specify good glazing: double glazing as standard, with options for solar-control glass to reduce overheating on south-facing rooms, or acoustic glass if you are near a road. A thermally broken aluminium frame keeps the room comfortable year round and meets current Part L requirements.

Thresholds, colour and system

  • Threshold — a low or flush weathered threshold gives a near-level transition to the patio and is more accessible, while a standard threshold offers the highest weather resistance
  • Colour — anthracite grey (RAL 7016) is the most popular modern finish, but aluminium can be powder-coated in almost any RAL colour, including dual-colour inside and out
  • System — premium systems such as Schüco and Cortizo offer slimmer sightlines, strong security and long guarantees; the right one depends on your budget and the look you want

Finally, coordinate the doors with your builder early. The structural opening, lintel and floor level all need to suit the doors you choose, so it pays to confirm the specification before the brickwork goes up.

Planning an extension? Tell us your opening size and we will help you specify the ideal bifold doors and send a free quote — supply only or supply and fit.

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