Choosing bi-fold or sliding doors

Both bi-fold and sliding doors let in light and link the inside of your home to the garden. Sarah Warwick explains how to choose the right option for you

TODO alt text

Modern glazed doors, whether they be bi-folds or sliding, are one of the most sought after features in today’s homes. Equally, they are one of the main additions people use to flood their houses with light when undergoing an extension, or renovating their property.

Choosing the right bi-fold or sliding doors for your house is important, both practically and stylistically and they could quite easily become the wow-factor feature that you have been looking for. To make sure you make the right decision, follow our guide to choosing the perfect glazed doors for your project.

What are bi-fold doors?

  • Bi-fold doors – which are also known as folding-sliding doors – slide open panels concertinaing neatly together.
  • They can also include a standard-style door at one end, which you can use to go in and out without having to fold the panels.
  • Bi-folding units can open inwards or outwards, and most people choose the latter option to maximise space inside. With examples that open outwards, you don’t need to worry about the furniture inside the room getting in the way of the folded leaves when the door is open.
  • ‘With a bi-fold door you can open up a whole wall giving a connection to the exterior space,’ explains Matt Higgs, co-owner and sales manager at Klöeber.


These double-glazed Schueco ASS 70 FD bi-fold aluminium frames and integrated blinds cost about £15,000

What are sliding doors?

  • Sliding doors open by moving to the side, with the panes fitting behind one another.
  • You won’t be able to fully open the room in which they’re fitted to the outside.
  • Hidden pocket versions are possible, allowing the sliding doors to be inserted into the wall to create a complete open wall,’ says Bryony Sandy, marketing and sales assistant at Hedgehog Aluminium Systems.
  • ‘With a sliding door you get the benefit of larger expanses of glass and the view isn’t impaired by as many frame lines when the door is shut,’ adds Matt.
  • Sliding doors are a popular option when space is limited because they don’t require room to manoeuvre inside or out.


Sliding doors with a powder-coated aluminium frame and solar-controlled double glazing, from £15,000, Apropos

How much do bi-fold and sliding doors cost?

You’ll need to budget from £480 per square metre for bi-fold doors with an aluminium frame, and £600 per square metre for sliding doors.

Bear in mind that for both sliding and bi-fold doors, the frame material and its dimensions will influence the cost. As a rule, uPVC offers the least expensive option and aluminium the most.

Panel sizes also affect the final cost of your selection. You might want to factor in whether the doors have integrated blinds or if you’re going to buy a window treatment separately for use in the evening. Finally, don’t forget that both off-the-shelf and bespoke glazed doors are available, but you’ll pay accordingly.

ID systems sliding doors

With aluminium frames, these Grand Slider II double-glazed, single-panel sliding doors start from £1,440 per metre, ID Systems

Glazed door materials

Popular glazed door frame materials include metal, wood, uPVC and composites. ‘The first thing people should consider is the type and period of their property, closely followed by the maintenance involved in the chosen material,’ says Noreen Williams, group marketing and

  • A traditional property may suit engineered hardwood timber, but bear in mind that these doors will need to be repainted or stained regularly to keep them looking good.
  • Composites, which are made from various materials, including insulating foam and glass reinforced plastic, can give the external appearance of timber but with none of the maintenance issues.
  • Metal frames, such as aluminium, are also easy to care for, and give a more modern look.
  • uPVC maybe the best choice If budget is key, or you’re trying to match your new doors to your current windows, but this is limited to white and foil options.
  • The material will also affect the dimensions of the frame – and therefore the amount of glass you can have – with aluminium generally being the thinnest and uPVC the thickest.

An entirely glazed corner created with sliding doors can look spectacular but may need a supporting column where two doors meet. ‘Structural steelwork must be designed suitably for the space,’ explains Andrew Sweeney, of Care Building Services. ‘And a structural engineer’s survey has to be carried out before designs can be drawn up.’


These engineered oak bi-fold doors are finished in a light oak stain, they cost £4,139, from Klöeber’s Eurofold range

How long does installation take?

The system and size of the doors will determine how long your doors take to put in. ‘Ideally, the installation should be one of the last elements of a build process to ensure the doors, and probably most significantly the track, are protected from ongoing construction work,’ explains Carl Farrow, technical development manager at ID Systems.

‘A typical installation would see our engineers arrive on site first thing in the morning, and pack out the opening before installing the outer frame of the system. This would then be followed by the track installation and fitting the doors. The final stage is a test and adjustment of the system to ensure the doors are running perfectly, before spending time with the customer to ensure they know how the doors operate, and how to look after and maintain them.’

Typically, a bi-fold door of up to six panels would be completed inside a day by a single team of engineers, says Carl. A larger system, including doors with bigger panes of glass and complementary products such as glass roofs, may take multiple engineer teams two or three days.


KAT aluminium bi-fold doors from Access Garage Doors, from £3,495 for a three-pane bi-fold 

Should I choose double or triple glazing?

Glazed doors can be either double or triple glazed. ‘Over the last five years, we’ve seen a steady rise in the demand for triple glazing as building regulations become more stringent and the industry becomes increasingly conscious of the thermal efficiency of homes,’ says Neil Ginger, CEO at Origin. ‘However, in some cases, the efficiency of high-performance double-glazed doors and windows is almost as good as a triple-glazed system.’

When you’re selecting the glazing option, pay attention to its U-value, which measures the heat insulation properties: the lower, the better. You’ll usually find that the higher cost of triple glazing is not reflected in a lower U-value, making double glazing the best option.

Measuring and ordering

Most suppliers recommend calling in a glazing specialist for measuring and ordering– although taking on the job yourself is possible. ‘You can measure by taking multiple dimensions across the width and height of the aperture, taking the smallest of these and taking off a tolerance (an allowable amount of variation) identified by your door supplier,’ says Matt Higgs at Klöeber. A reputable company can talk you through the ordering process, and give you technical drawings and instructions to help you.

You’ll always need specialist help with the installation process – make sure the glazing installer you choose is Fenestration Self-Assessment Scheme approved by searching online at