Can Bi-folding Doors be frameless?

Unfortunately you can’t have a completely frameless bi-folding doors as they won’t meet building regulations. As standard all bi-fold doors and any external doors need to meet U-values of 1.8W/m²K (a U-value is simply the measurement of the rate of heat lost through a material). Achievable U-values will depend on the size of the door panel, the type of frame, sealants used and also glazing and glazing coatings.

Bi-folding doors with slim sightlines and sliding corner 

The best way to achieve a near frameless look is to opt for a system with very slim sightlines (which is basically the width of the frame). Aluminium bi folding door systems on the market will tend to have a more contemporary design and often have much slimmer frames, for example Sunfold Systems' SFK70 system, is just 100mm. Quality will play a large part in the stability of the bi-fold doors and the higher quality systems will have been specially designed and tested to be capable of providing the required support whilst also achieving that as near frameless look as possible. Most off the shelf systems will have much thicker bulkier frames as standard such as uPVC. 


Some folding door companies will offer very tall heights without additional support but this has a detrimental effect on the sightlines as they usually need to incorporate some kind of post/additional profile in between the hinge section – this is where their support comes from (as opposed to midrails/horizontal transoms). The effect then when the doors are open is chunky and you also achieve less opening space as the doors can’t fold as flat to one side. 


Frameless systems on the market with a similar concept such as sliding stacking doors (doors which stack to the side rather then fold and slide) will not provide thermal efficiency but tend to be used more for weather protection for areas such as porches or balcony areas where a fully insulated door system acts as a divide.