air 800 folding doors

Who makes the slimmest bifolding doors?

The aluminium bifolding door offers a host of benefits in the home, but what are the slimmest bifolding doors available at the door mullions? With more bifolding door systems available than ever before, if you are a homeowner looking for a quality bifolding door, there is a tremendous amount of choice. One area you may be considering is the appearance and aesthetics at the door mullion.  For the trade, this article helps you compare the majority of the UK systems, useful to compare against the products you do sell.

Who makes the slimmest bifolding doors?

One of the promoted features of the bifolding door is the ‘door sightline’. The door sightline is the visible aluminium you see on a closed set of bifolding doors.  This is where the door panels meet or referred to as the door mullion.  

Here is our table illustrating the sightline of virtually every major aluminium bifolding door system available today. See how they compare in order of slimness at the door mullion and the sightline dimension you can expect to see.

Schuco ASFD7590mm
Smart Systems Visofold 600094mm
Solarlux Ecoline and Highline99mm
Solarlux SL80105mm
Dutemann FD85 (Alumil SF85)105mm
Express Bifolds XP Vision (Alumil SF85)105mm
Origin OB-49 Bifolding Door110mm
Greenways Ultra Slim Bifolding Door110mm
Schuco ASS 80FD112mm
Sunflex SF75115mm
Schuco ASS 70 FD120mm
Comar FSDX Folding Sliding Door120mm
Cortizo Bifolding Door120mm
DeWall Bifolding door by Debar120mm
StudioGlide by Eurocell (DeWall product)120mm
Alutech BF73 Bifolding Door120mm
Unifold by Arkay Windows120mm
Deceuninck Decalu88 folding doors120mm
Air 800 Bifolding Door122mm
AluK Luminia F82 Bifold Door122mm
Reynaers CF 77 SL122mm
Senior Architectural Alifold Doors123mm
Senior Architectural PUReFold Doors123mm
Sunparadise Supertherm 80 Bifolding Door124mm
Sunparadise Thermo 60 Bifolding Door124mm
Stayfix Architectural Vision Fold Doors125mm
Folding Sliding Door Company FD72130mm
Velfac 860 Bifolding Door130mm
Reynaers CF68131mm
SAPA Crown Folding Door with slim sash131mm
Smart Systems Visofold 1000132mm
Exlabesa Xlafold Bifolding Door135mm
Centor C1 Bifolding Door136mm
Sheerline Prestige Bifold Door138mm
AluK Optio BSF70 Folding Sliding Door140mm
Sieger Bifolding Door140mm
Smart Systems Visofold 2000141mm
Metal Technology Bifolding Door143mm
Technal Ambial Bifolding Door143mm
Reynaers CF77144mm
Panoramic Slide and Turn Door145mm
Kawneer AA3720 Bifolding Door145mm
Stellar Aluminium Systems Bifolding Door146mm
Kestrel Folding Sliding Door150mm
Metal Technology System 26 HI+ Bifolding Door153mm
Origin OB-72 Bifolding Door154mm
Smart Systems Visofold 3000154mm
Alumina by Liniar156mm
Warmcore Bifolding Doors156mm
Solarlux SL70157mm
SAPA Crown Folding Door standard sash165mm
Aluprof MB System Bifolding Door166mm
Smart Systems Visofold 4000185mm

How do we arrive at our list of the slimmest bifolding doors?

The data for fifty folding sliding door systems comes from the system company websites or their technical and fabrication manuals.  The above sightlines indicate the typical dimension where two intermediate panels meet. Sizes with some systems increase when a folding panel meets the traffic door if one is specified.  We excluded frameless and slide and fold doors operating on an individual moving and folding panel basis as well. Also excluded are systems that do not meet current Building Regulations.

However, there are two bifolding door systems even thinner than the Visofold 6000 bifolding door, top of the list above. We did not include these two in the list above because these are structurally glazed bifolding doors, made around the glass. The above systems are dry-glazed.

solarlux slimmest bifolding doors

The Sieger Lux Bifolding Door.

Our research shows the overall slimmest bifolding door on the market in the UK right now, to be the Sieger Lux product. This boasts impressive 30mm wide door sash profiles with integrated locking systems. As a result, these give an overall mullion dimension of 74mm.

Unlike the doors above, the Sieger Lux bifolding door comes structurally bonded and allowing the glass to take the weight of the product, reducing the aluminium sightlines as a result.  Studying the section drawings of this product reveals thermally insulated aluminium profiles, bonded to 28mm double glazed or 32mm triple glazed units.

Square edges, slimline door components, 3-point locking system, open corner option and traffic doors are just some of the standard features you get. Minimal aluminium frames combined with high specification glass units also provide U-Values of 1.6Wm2K depending on the glass used.  As well as this, you get the expected large bifold panel sizes of up to 1.2m wide and 3m high. This is one outstanding door for aesthetics and design and well worth checking out.

The System 48 bi folding door by Fineline Aluminium.

Even thinner than the Sieger Lux bifolding door is the System 48 Bifolding Door by Fineline Aluminium of Weston Super Mare. The System 48 Bifolding door offers a remarkable 48mm sightline and beats the Sieger by quite a margin.

However, the aluminium sections are not, strictly speaking, door sash sections, and it uses different hardware for the slide and fold operation.  The locking systems are located on the rails rather than the door stiles too.  Moreover, with such narrow sections, most lock cases cannot fit in such thin sections.  While very much a bifolding door worthy of consideration, we felt the System 48 bifold as being far too different in its design to be included in our table of ‘conventional’ bifolds, that mostly share a similar construction. But it is a fantastic-looking bifolding door with impressive thin proportions.

frameless bifold doors

The frameless folding sliding Door.

It is worth giving a mention to the frameless bifolding door. These are minimal-framed slide, stack and fold products that, chosen correctly, provide even thinner sightlines.  If you want even less visible aluminium, then check out frameless bifolding doors.  Sunseeker doors have a mullion sightline of 38mm using a plant-on profile to cover the glass edges.

Frameless Glass Curtains by FGC of Chatham has no visible mullion and only a minimal gasket sight line where the door panels meet. Smart engineering, a patented glass spacer bar and sophisticated gaskets make these doors incredibly thin. Therefore, if you want as much glass as is possible on a bifolding door, we suggest you consider these.  A different kind of bifold in design and operation but also a contender amongst the slimmest bifolding doors.

If you are wondering why some well-known big retail brands are missing, this is because many use the above systems or variations of them. This includes well known retail companies such as:

  • Express Bifolding Doors using Schuco, Alumil and Smart Systems
  • Bifold Direct
  • Everest Home Improvements
  • Anglian Home Improvements
  • Kloeber using Schuco
  • Duration Windows using Smart Systems and Aluk

Are slimmer bifolding doors better?

No.  AluK, Smart Systems and Origin are three bifolding door brands in the UK with excellent sales, given the size of the systems companies by turnover and the volume of bifolding doors supplied. This is despite their doors not being the slimmest on the market.  It’s the same with the new bifolding door from Stellar Aluminium Systems. They too don’t have the slimmest bifold on the market but their entire suite of windows and doors is new, innovative and worthy of consideration.

Centor bifolding doors are probably one of the best on the market. Yet these aren’t the slimmest.

Ultimately a buyer and a manufacturer of bifolding doors takes many different factors into account and not just the bifolding door sightline.  However, with the bifolding door market established and with more than 30 systems available, customers have never had more choice.

Recent slim bifolding door products include the air 800, the Dutemann FD85, the Exlabesa Xlafold and the Smart Systems Visofold 6000.  The Comar bifolding door is as thin as the better known Schuco door.  All these products are designed with a narrow bifolding door sightline as an ultra-slim door is often perceived as being more desirable.

What to consider when buying bifolding doors.

The sightline is just one consideration when buying a bifolding door.  It is not just about the slimmest bifolding doors.  Here is what else is more important.

  • The overall product aesthetic and how it looks like a complete door not just in one area.
  • The more door panels, the less intrusive the mullion can appear.
  • The quality of the hardware, locks and bifolding door handles.
  • The colour, handle, configurations available and other personalisation options.
  • The security and weather performance of the product.
  • The U-Values provided if energy efficiency is important to you.
  • The guarantee available with the product.
  • Your confidence in dealing with the company providing you with the doors.

If you’re also considering sliding doors, take a look at who makes the slimmest sliding doors in aluminium.

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