A decking on the beach with Solarlux bi-folding doors behind

Megaline Bi-Folding Door

With a maximum panel height of 4.5 metres or a panel width of up to 1.5 metres, the Solarlux Megaline bi-folding door can be used to create incredibly large glass surfaces – without compromising on convenience.

Megaline “Pushes The Limits” – A New Market Innovation

The aluminium Solarlux Megaline bi-folding door with excellent thermal insulation is designed for use wherever extra-tall or wide panels are required. It is predestined for use in commercial premises, such as restaurants, shops and public buildings, as well as unique private homes that aim to impress with its special structural features.

With a building depth of 84 mm, a maximum panel height of 4.5 m (or a panel width of up to 1.5 m), it can be used to create incredibly large glass surfaces without compromising on ease of use or movement. At the heart of the bi-folding door: the bionicTURTLE®, a multi-functional break profile that combines a range of technical details. This innovation helps keep the profiles slim – even when using large and heavy panels, it also houses the locking mechanism and guarantees perfect insulation.

The specially shaped stainless steel running tracks allow for the use of unguided carriages, and can be used with a selection of floor tracks, including accessible variants in accordance with DIN 18040. Depending on the height of the system, multiple sets of system hinges can be installed above one another. This guarantees a high degree of stability for the panels – which can weight up to 150 kg each – even at high wind loads. For extremely structurally demanding locations, additional structural profiles can also be added in the panel joint areas.

Other aluminium Solarlux bi-folding door alternatives include the Ecoline and Highline.

Technology at a glance



Air Permeability


Water Tightness

Up to 7A

Thermal Transmission Coefficient

Uw > 0.9 W/m²K



System Description

Megaline Bi-folding Door Profile System

  • Modular aluminium profile system with excellent heat insulation and building depth of 84 mm
  • Bottom-running; minimal load support required in case of falls
  • Edged profiling
  • Sight line of 132.5 mm in the panel butt joint, further structural profiles can be added in the panel butt joint areas depending on structural requirements (e.g. extreme wind loads).  This results in a sight line of 129 mm in the panel butt joint
  • Single-piece, multi-functional, fibreglass-reinforced polyamide bionicTURTLE® break profile
  • Loose shear bond built into thermal break to compensate for thermal loads
  • Mitred panels connected by corner connections that are glued and pressed together on the inside to create a sturdy joint
  • Controlled drainage
  • Built-in running tracks and guide rails
  • Separate levels for runners and locks
  • Floor track (accessible and suitable for living spaces) available
  • Built-in, concealed cable routing

Sealing System

  • The seal encompasses two all-round sealing levels with constant gap sizes and even seal pressure between the panels
  • Sealing levels not interrupted by fittings
  • Sheathed foam seals with optimum sliding properties
  • With optional convection chamber interruption seals for improved thermal transmittance
  • Up to three sealing levels available

Design Variants

  • Panels fold either inwards or outwards, to either left or right
  • Floor track designs without rebates in compliance with German standard DIN 18040 on “Accessible construction”
  • Floor tracks available as minimal floor tracks without height offset


  • No upstream running tracks or guide rails
  • Fittings with one-hand operation in profiles
  • With optional built-in TwinX concealed panel centring mechanism for high wind loads
  • System hinges also suitable for heavy panel weights
  • System adjustment mechanism built into sub-frame rebate, outside the sealing level
  • The specially shaped stainless steel running track with tapered track roller allows for the use of unguided carriages
  • Stainless steel ball bearing runner mechanism: low-noise, extremely durable stainless steel track roller and bearing surface
  • Easy-running, low-wear carriage fitted with double-row deep-groove ball bearings and built-in anti-prying guard
  • Sliding lock or optional lockable panels for controlled ventilation
  • High-quality, stainless-steel Solarlux designer handles
  • Lock-in-place, one-hand operation thanks to special gears with 24 mm latch bolt
  • Passdoor available with latch-key-activated, multi-point lock and profile cylinder
  • Secure hinge pins
  • Lock monitoring system with reed contacts and concealed cable routing
  • Optional load-transferring installation plates with centring grooves and sealing cushions for mounting the sub-frame profiles and floor track
  • Additional mounting screw covers in frame rebate


  • Sustainable manufacturing
  • Certified disposal in accordance with DIN EN ISO 14001:2009


  • In-house production control
  • Tested in accordance with DIN EN 1090, design class EXC 1 & EXC 2
  • Certified in accordance with DIN ISO 9001

Find out more about the Megaline bi-folding door on the Solarlux website here.

Solarlux World Of Colours

Solarlux products are available in any RAL colour. The stand colour palette includes around 30 RAL colours in both matt and gloss finishes at no extra cost.

RAL 1015

RAL 3011

RAL 5003

RAL 5008

RAL 5014

RAL 6005

RAL 6009

RAL 7004

RAL 7006

RAL 7015

RAL 7016

RAL 7021

RAL 7024

RAL 7035

RAL 7038

RAL 7039

RAL 7040

RAL 8017

RAL 8019

RAL 8022

RAL 8077

RAL 9001

RAL 9003

RAL 9004

RAL 9005

RAL 9006

RAL 9007

RAL 9010

RAL 9011

RAL 9016

What Our Clients Say

See All Testimonials

Kevin, Dorchester

Had VELFAC windows and doors fitted recently on a project by Composite Windows UK. Great company to deal with. Very helpful in the ordering process and the fitters were a pleasure to deal with. No hesitation in using and them again.

Chandra, Hove

I have had Velfac windows and external doors for 12 years. One window was not fitted properly by the developer (not Westcott) and had been leaking and needed replacing. The window was on a 4th floor flat and access difficult. Westcott were recommended by Dovista and Westcott worked timely from survey to order and then to sync with scaffolders dates to install. The guys had difficulty getting the frame up to 4th floor but they stripped it down and hoisted it up to the 4th floor. The job was professionally completed in a day. I am very pleased with the result and would recommend Westcott. Particular thanks to the boys who were all courteous and professional- Adam, Gavin, Matt and Andy. The office staff were always prompt with replies too. Thank you all.

Andrew, Pagham

We were recommended to use Rationel windows and Solarlux bifolds by an architect friend and Composite Windows are the local supplier. Very good service, great windows – well worth the money.

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