The FD85® represents the completion of three-year project and the third product Dutemänn has brought to market with its aluminium extruder partner Alumil.

The FD85® project had three main design briefs, the product had to have market leading U-values, Innovation it had to move the bi-fold market forward and it had to meet all industry security standards.

The FD85® is a feature packed Bi-folding door system that is aimed at the more discerning home owner, architect or builder. These end users will be able to specify FD85® though our nationwide network of approved partners. Whether the end client wants great U-Values, great security or great innovation the FD85® has it all.

There has been great industry interest in the Quad-bolt™ system which is standard on and exclusive to the FD85®. Quad-bolt™ is one of the design features that both Alumil and Dutemänn are most proud of, this innovation will give end clients everywhere the added security they crave.

Initial field trials suggest that FD85® will be the “fitters friend” with its easy fit outer frames along with hinge and lock adjustment. The outer frame has been designed with corner setting blocks for quick, efficient and trouble free installation. Once the frame is in place it is a simple matter of installing the panels and glazing.


The FD85® is packed with security features including the Quad-bolt™ system that have helped us attain PAS24:2016. Every FD85® bifolding door will leave our factory built to this exacting security standard, meaning that our clients will comply with part Q of building regulations for new build dwellings.


The FD85® has excellent overall u-values more a-kin to a hybrid system. At the “test standard size* using a standard ‘off the shelf’ double glazed unit the door returns a U-value of under 1.5(W/m²K). This achieved by designing thermal efficiency into every aspect of the door. (*Test size as outlined in Approved document L1B x 2.0mtr, door consists of 2 panel)


The FD85® has undoubtedly moved the market on, it has numerous design features including:

  • The 105mm mullion among the slimmest doors available
  • The FD85® has the ability to make panels up to 1.35mtrs wide allowing the client to specify a three panel bifolding door with a maximum overall width of 4.050 mtr!