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Bi-Fold doors – open up your world.

The jewel in the crown of the Alumina range – our bi-folding door system enables a full wall of your home or property to be opened up to the outside.

Ideal for commercial or heavy duty applications, Alumina sliding bi-fold doors offer added strength and security.

Spanning up to 7 panes wide, Alumina bi-folding doors can be supplied with almost any powder coated RAL finish, or foiled with a realistic factory fitted woodgrain foil.

A true aluminium bi-fold system, Alumina doors are available with 28mm double or 36/40mm triple glazing, offering U-values as low as 1.3W/m²K.

Why choose Alumina bi-fold doors?

With sash sizes from 0.6m to 1.2m and up to 2.5m high, Alumina bi-folding doors are ideal for heavy duty or commercial applications,

Built with Liniar’s ModLok™ technology and thermal patented polyamide lock, Alumina bi-folding doors can achieve a U-value as low as 1.3W/m²K.

Alumina bi-folds can also be fully foiled to perfectly match the Liniar range of windows and doors, or powder coated in any RAL colour of your choice. Even better – by matching windows and doors this offers a single point of guarantee for the homeowner.

Colour options

Alumina bi-folding doors are supplied as standard in plain white, black or grey powder coated finishes. Your fully aluminium doors can also be personalised by choosing almost any RAL colour.

Alumina can also be ordered with a wide range of different colour precision fitted foils, ensuring a perfect match to Liniar PVCu windows.

Click here to see the full colour range.


Threshold options

All Alumina doors are available with a choice of five threshold options – including the rebated aluminium frame to the 23.5m high low threshold and the Part M compliant threshold with tray.

A full size Alumina door has also been weather tested with a thermally broken threshold, achieving incredible results – beating the minimum requirements for both air and water tightness by more than double the most severe pressures within BS 6375.

Click here to view all threshold options.

Alumina is brought to you by the same team of experts as the innovative, energy efficient, PVCu Liniar window system.

The Liniar design team has now developed three bi-folding door systems from scratch, giving consumers the ultimate in choice and flexibility when it comes to selecting the best bi-fold to fabricate, to install and to use every day.

Standard bi-fold

The very first bespoke designed uPVC bi-fold to be designed and launched in the UK, Liniar’s Standard bi-fold features thermally efficient profiles, slim fixings with hidden hinges for additional security and is available up to 4 panes wide – all in a wide choice of colours, finishes and threshold options. Bottom rolling, the Liniar Standard bi-fold doesn’t require additional strengthening of existing lintels as all the weight is on the bottom of the doors. With U-values as low as 1.3 W/m²K, the Standard bi-fold is a cost-effective and secure bi-folding door system.

ModLok™ bi-fold

Launched in 2014, the patented ModLok bi-fold system offers a high-security locking mechanism with combined reinforcement, and offers the highest thermal efficiency of any Liniar uPVC bi-fold, at just 1.0 W/m²K. Its beautifully sleek appearance and detailed design features make it a popular choice for both modern and traditional dwellings, and it can span up to 7 panes wide in a variety of opening configurations. With PAS 24 and Secured by Design accreditation, the ModLok bi-fold has been cyclic tested by robot to more than 12 times British Standards.

The ModLok bi-fold system also won a coveted Queen’s Award for Enterprise in the Innovation category in 2017, in recognition for its patented exoskeletal structure. This prevents the contraction and expansion of uPVC, making ModLok bi-folds suitable for high traffic entrances up to 7 panes wide.

Alumina bi-fold

The very latest development from the Liniar team, Alumina is a ‘true’ aluminium bi-folding door system that encompasses the highest degree of energy efficiency combined with an optional ‘warm touch’ foiled exterior. Ideal for large scale and commercial applications, each pane of an Alumina door can span up to 1.2 metres wide and 2.5 metres high, and up to 7 panes across. With PAS 24 and Secured by Design accreditation granted at the first attempt, the Alumina bi-fold also offers the ultimate in security.

Use our handy comparison table to choose the most suitable bi-fold system for your intended application:

Standard ModLok Alumina


Max no. of Panes 4 7 7
No. of Door Styles 6 16 16
Max Width (Sash) 0.8m 1.0m 1.2m
Max Width (Outer Frame) 4m 6m 6m
Max Width (O.Frame, Foiled) 4m 4m 6m
Max Height (Sash) 2.15m 2.15m 2.5m
Part M Threshold
Thermally Broken Alum. Threshold  ☓  ✓  ✓


Double Glazing 1.3 1.3 1.5
Triple Glazing 1.0 1.3


Foiled Finishes
Powder Coated




Std. Manufacturing Machinery
Supplied Bar Length Bar Length Fabricated


Perfectly matched

Choose Liniar Flush Sash PVCu windows for a seamless match between your windows, flush door and aluminium bi-fold.


Fully guaranteed

Homeowners can register their Alumina Flush door online to take advantage of our guarantee.


Sash size

Ideal for commercial and self-builders, the sash in an Alumina flush door can span as large as 1.2m wide and 2.5m high.


PVCu accessories and add ons

Choosing a foiled finish means installers can benefit from utilising the full range of Liniar PVCu beads and add ons.


Glazing options

Choose from 28mm double glazing or 36mm or 40mm triple glazed options.


Combined thermal lock

Suitable for high traffic entrances or commercial applications, the Alumina flush door is built with Liniars ModLok™ technology.