Trade supply aluminium bifold doors

With excellent design, impressive aesthetics and built to last, our aluminium bifold doors create open-plan living and a sense of space. Closed, the ultra-slim profiles allow the maximum amount of glass, light and impressive views. Open, they connect inside and outside spaces, fully opening up to the patio or garden and with a standard or flush threshold option.

Ideal as a modern replacement for dated patio doors and also designed to enhance any new build extension, we custom-make our bifolding doors for homeowners arranging their own installation, the glazing trade, builders or property developers. An excellent addition to any home and also suitable for commercial buildings including offices, cafés, restaurants and bars.

Premium Quality Bifold Doors

Expertly manufactured in our modern factory, our trade supply aluminium bifold doors deliver on quality, performance, and are also some of the slimmest on the market.

Latest Generation Bifolds

Insulated profiles, attractive colour finishes, and stylish hardware, with superb build quality, fit and finish.

Bespoke Bifold Doors

Made to measure to your precise sizes, configuration, colour and accessories.

Smart Design

Suitable for replacement doors or new build openings, ready to fit and glaze.

Alunet BF73 bifold doors in a modern room setting

Alunet BF73 bifold doors

With superb engineering and overall design, Alunet BF73 bifold doors provide all the best possible features required from a quality bifold. Slim sightlines, premium aluminium frame profiles, robust build quality and high specifications create an affordable bifold door without compromising features. 23 DOORS are specialist manufacturers of Alunet BF73 bifold doors, carefully crafted, delivered on time and with impressive features for a fast and easy fit and glaze.

One of the slimmest on the market

With an impressive slim door mullion sightline of just 120mm and 107mm frame to sash, Alunet BF73 bifold doors are unbelievably slim, promising genuine customer appeal and an excellent solution for residential or commercial customers. Slimmer than the leading bifold door brands, the BF73 model promises less aluminium bulk, usually a feature of patio sliding doors, larger glass sizes, more light and better, unobtrusive views. 

Alunet BF73 bifold doors partially open with wood floor and patio views

Stylish bifold doors

With a choice of frame profiles, including a flat or curved sash option, Alunet BF73 bifolds come as modern doors with a flatline profile or a softer overall appearance, ideal for character properties. A choice of cills, ancillary profiles, extension pieces and add-on sections ensures the doors can integrate within any new or existing opening.

Secure and Energy Efficient

Alunet BF73 bifold doors can achieve U-Values down to 1.4 W/m2K, with extensive sealing and weather protection. Premium door hardware with multi-pointAlunet BF73 bifold doors locking and security cylinder provides protection, and tested to PAS24:2016 and Document Q for new build homes.

Alunet BF73 bifold doors grey colour, closed outside view with integral blinds.
cross section drawing of Alunet BF73 bifold doors

Key Features

  • Thin 120mm mullions.
  • Panels up to 1.2m wide and 3.0m high.
  • Secure, insulated and weather-resistant.

Product Colours

We supply our bi-folds in black, white and anthracite grey as standard, but we can offer any bespoke colour option on request.



Anthracite Grey

RAL Colours

Better bifolds by design

One of the newest doors on the market, Alunet BF73 bifold doors, are designed by Alunet Systems, a leading systems company in the UK. The extruded aluminium profiles are created to the latest performance standards, with a professionally applied powder-coated finish. The renowned Debar brand of hardware provides a smooth slide-and-fold action, operates and secures the intermediate panels and ensures your new bifold doors are functional, reliable, long-lasting and low-maintenance.

23 DOORS – trade supply bifold doors expertise

Manufactured by us with precision and care, our trade supply bifold doors service is efficient and reliable, with our doors provided at impressive prices and lead times. Your door leaves are provided fully fabricated, with the outer frame in easy-to-assemble kit form. Glazing beads, cills, and add-on extension pieces are provided cut to size. Accompanying your bifold doors is easy to identify component kits and full installation instructions. Alunet BF73 bifold doors also come with an adjustable frame jamb, making final adjustments a breeze.

The benefits of modern aluminium

Slimmer than PVCu or timber, with less thermal expansion and optimum reliability. Aluminium bifolds are trusted for their strength, smooth operation, virtually unlimited colour choice and impressive design. The insulated profiles work with high-specification safety glass creating energy-efficient doors and helping save money on energy bills.

Virtually unlimited designs

When you choose Alunet BF73 bifold doors, you benefit from a fully flexible product. Doors can open in or out, with panels sliding in one direction or split to stack on each side. Numerous configurations include fixed or open corner designs of up to 7 panels each side, with built-in French or single doors. Even better, designed with a traffic door, you can use the doors just like a regular access door without having to fold all the panels back.

Create standard or oversized bifold doors

With door panels up to an impressive 1.2m wide and 3.0m high, Alunet BF73 bifold doors work in virtually any design, from a standard door opening up to architect designed project maximising the use of glass and slimline aluminium.

Matching single or double doors

Creating a complete home solution, we can also manufacture single or double doors for other door openings on a project. Created with the same slim bifold profiles, you benefit from matching aluminium doors from the profile design right up to the door hardware. And they come in larger sizes than other residential door systems, removing the need for additional toplights or side panels.

Frequently Asked Questions

23 DOORS are expert bifold manufacturers and can answer any of your questions relating to buying, choosing or understanding this popular, functional and stylish patio door. Contact us for expert help and advice.

How can I tell when bifold doors are high quality?

Premium aluminium profiles, a durable and high-quality colour finish, excellent components and a smooth sliding and folding action.  These are the best ways of identifying a quality bifold door.  

What is the advantage of a bifold door?

There are certain features you only get with a bifold, which is why they remain a popular product. Bifolds are the only doors that can open up your entire opening.  At the same time, only a bifold gives you the functionality of hinged doors with the benefit of folding fully open when configured with a traffic door.  Bifold doors also come with external key access, which is hard to get with sliding doors, letting you use your bifolds to get into a property.  Finally, bifold doors come made as single or double doors, giving you matching exterior doors throughout your property and are available at bigger door sizes than regular hinged doors. 

Which bifold doors are best?

The best bifolding doors are those that offer a combination of the best features. Slim sightlines are desirable, as the closed doors give you more glass, less visible aluminium, more light and better views.  Thermally enhanced profiles make the best bifold doors very energy-efficient. Above all, ensure your bifold doors are well-made and expertly fitted and you’ll get long-lasting, reliable, functional and secure doors. 

Why should I choose Alunet BF73 bifold doors?

Alunet BF73 bifold doors deliver some of the best features and highest specifications you can get in a bifold at a fantastic price. First of all, they are one of the slimmest bifold doors on the market, with a 107mm mullion sightline. Next is their impressive size capability, with door leaves up to 1200mm wide and up to 3000mm high. They create matching single or double doors and even front doors, and you can customise them with the on-trend steel look. They even come with features that make fitting them a breeze compared to other bifold doors. 

What are the different types of bifold doors?

The different types of bifold doors depend on the size of your opening.  Bifold doors start from two panels all the way up to seven or more.  They can open in or out, they can all slide to one side or split to both sides.  They are available with a low threshold connecting inside floors to outside decking or slabs. Bifold doors also come in the industrial, heritage or steel look, as fixed or open corner designs and can even work inside the home as stylish room dividers. 

Why are bifold doors no longer popular?

Bifold doors remain incredibly popular with features and functionality you can’t get with sliding or traditional hinged doors.  They are reliable, secure, and energy-efficient.  Chosen right, they are also slimmer than French doors. Even better, bifolds can be better than other doors in smaller houses because they fully open, connecting the room to the outside space and making the room and home feel larger, brighter and more spacious. 

What are the problems with bifold doors?

There is no problem with modern bifold doors when properly made and, importantly, correctly fitted. It is bad manufacturing and installation that causes problems with bifold doors, not the product itself.  Assuming you choose a quality bifold from a reliable manufacturer and installer, these doors will serve you very well for many years. 

Do bifold doors make a room cold?

No. All doors intended for the outside of a property come with thermally insulated aluminium profiles.  These insulated profiles work with high-specification safety glass and create a door with excellent insulation and low U-Values, helping lower your energy bills. 

Design Online

Our online door designer lets you create your own bi-fold door in your choice of style and colour and request a quote direct.

Design Online