The Short Answer
On our estimates, aluminium bifold doors for an opening up to 3m cost £3,600 to £5,400 supplied and fitted, rising to £7,200 to £9,000 over 5m. uPVC bifolds are cheaper (£2,400 to £5,400) and timber dearer (£4,200 to £9,600). A straightforward fit takes about a day.
Widening the opening is where budgets go wrong. A wider opening needs new beams to carry the wall above, usually designed by an engineer and approved by building control, plus making good: typically £2,500 to £5,000 on top. Sliding doors give a similar view for less: £2,500 to £5,000 in aluminium.
Bifold doors cost calculator
Width sets the price more than anything, then the frame, then whether the wall needs opening up.
Estimated total
£3,600 to £5,400
| Up to 3m (3 panels), aluminium, supplied and fitted | £3,600 to £5,400 |
Bifold door prices
| Opening width (aluminium) | Supplied and fitted |
|---|---|
| Up to 3m (3 panels) | £3,600 to £5,400 |
| 3 to 4m (3 or 4 panels) | £5,400 to £6,600 |
| 4 to 5m (4 or 5 panels) | £6,600 to £7,800 |
| Over 5m (5+ panels) | £7,200 to £9,000 |
| Item | Typical cost |
|---|---|
| uPVC bifolds, 3 to 5 panels, fitted | £2,400 to £5,400 |
| Timber bifolds, fitted | £4,200 to £9,600 |
| Fitting only | £720 to £1,450 |
| Widening for bifolds (beams, engineer, building control) | £2,500 to £5,000 |
Widening the opening
The Planning Portal's guidance: reuse an existing opening and, as long as the span and load on the existing lintel don't increase, no extra support is normally needed. Make it wider and the wall above has to be carried, typically on one or, more usually, two new beams. Each beam normally bears at least 150mm onto the wall either side, the wall under those ends may need concrete padstones to spread the load, and a steel beam is normally protected against fire for at least 30 minutes, usually with layers of plasterboard.
Bigger glazing also brings in the energy rules: if windows, doors and rooflights would exceed about 25% of the floor area, compensating measures are needed. For the beam itself, see RSJ installation.
Building regulations and planning
- Same opening: replacement doors are controlled fittings: 1.4 W/m²K or the doorset energy rating equivalent, safety glass in the door and side panels, and a competent person scheme certificate (FENSA, CERTASS, Assure, Blue Flame, Certsure or NAPIT) or building control approval.
- Near a boundary: doors close to a boundary may need fire resistance to limit fire spread, the Planning Portal notes.
- Planning: not usually needed for doors of similar appearance in an existing opening; check if you're listed, in a conservation area, or it's part of an extension.
Bifolds or sliding doors?
| Bifolds | Sliding doors | |
|---|---|---|
| Open | Fold right back for a fully open wall, with a traffic door for everyday use | Slide over each other; open as much or as little as you like |
| Closed | More frames: panels up to about 1.2m wide | Bigger panes, slimmer frames, more glass |
| Panels | Any number, folding in or out | Usually 2, 4 or 6 |
| Price, aluminium | £3,600 to £5,400 (to 3m) | £2,500 to £5,000 |
My view: bifolds if you'll open the whole wall in summer; sliders if you mostly look out through it.
Get bifold doors quotes
Bifolds are priced by width and material, and by whether the opening needs widening.
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Frequently asked questions
How much do bifold doors cost?
On our estimates, £3,600 to £5,400 for aluminium bifolds up to 3m wide, fitted, rising to £7,200 to £9,000 over 5m.
How much are 3 metre bifold doors?
About £3,600 to £5,400 in aluminium, fitted, into an existing opening, on our estimates.
How much is a 4m bifold door?
About £5,400 to £6,600 in aluminium for a 3 to 4m opening, fitted, on our estimates. Widening an opening to 4m adds £2,500 to £5,000.
What are the disadvantages of bifold doors?
More frames across the view when they're closed than sliding doors, and the cost of widening if your opening is too small. Origin, a maker of both, says sliders have bigger panes and slimmer frames.
How much does it cost to widen an opening for bifold doors?
Typically £2,500 to £5,000 on our estimates for new beams, the engineer's design, building control and making good, on top of the doors.
Do bifold doors need planning permission?
Not usually into an existing opening. A new or widened opening needs building regulations approval; listed buildings and conservation areas need checking.
How we priced thisView sources (7, 6 official)
Rules come from the legislation and official guidance, read at source. Prices are our estimates: we check them against trade price data, retailer shelf prices and specialists' price lists, then build them up from their parts so the totals add up. Below are the sources behind the page; the trade price guides we only compare against aren’t listed. Where sources disagreed, we've said so. More on our method.
- OfficialBuilding regulations: structural opening, Planning Portal. Checked 15 Oct 2026.
- OfficialDoors and windows: building regulations, Planning Portal. Checked 15 Oct 2026.
- OfficialApproved Document L: Conservation of fuel and power, Volume 1 Dwellings (2021 edition incorporating 2023 amendments), GOV.UK. Checked 16 Oct 2026.
- OfficialApproved Document K: Protection from falling, collision and impact (2013 edition), Section 5, GOV.UK. Checked 15 Oct 2026.
- OfficialThe Building Regulations 2010, Schedule 3: self-certification schemes (para 16, roof coverings), legislation.gov.uk. Checked 15 Oct 2026.
- OfficialDoors and windows: planning permission and building regulations, Planning Portal. Checked 15 Oct 2026.
- IndustrySliding doors vs bifold doors, Origin. Checked 15 Oct 2026.
