Bi-fold doors cost UK 2026 — sizes, styles, installation
Real 2026 UK pricing for bi-fold doors by material, size and spec — plus the hidden structural and making-good costs most quotes don’t show upfront.
Bi-fold doors have become the UK’s most popular rear-of-house upgrade over the past decade — the kind of extension project that turns a cramped back garden into a full indoor-outdoor space. If you’re planning bi-folds in 2026, expect to spend somewhere between £1,800 and £8,500 depending on size, material, and spec. This guide breaks down exactly where those numbers go.
Typical UK bi-fold door prices in 2026 (installed, ex-VAT)
| Size | uPVC | Aluminium (standard) | Aluminium (slim profile) | Timber |
|---|---|---|---|---|
| 2.4m (2 panels) | £1,800 – £2,600 | £2,400 – £3,500 | £3,200 – £4,500 | £3,800 – £5,500 |
| 3.0m (3 panels) | £2,200 – £3,400 | £3,200 – £4,500 | £4,000 – £5,800 | £4,800 – £6,900 |
| 3.6m (3-4 panels) | £2,700 – £4,000 | £3,800 – £5,500 | £4,800 – £6,900 | £5,800 – £8,300 |
| 4.8m (4-5 panels) | £3,500 – £5,200 | £4,800 – £7,000 | £5,800 – £8,500 | £7,500 – £10,500 |
What drives bi-fold door cost
- Material: aluminium is UK market leader (~70% of installs) because of slim-profile frames — thinner frames, more glass. uPVC is cheapest but has thicker, visible frames. Timber is premium and suits traditional properties
- Panel count: 3-panel is the sweet spot for UK semis; more panels means more hinges + track complexity
- Glass spec: A-rated double glazing is standard; triple glazing adds ~20%; solar-control adds ~10%
- Threshold: flush (level with floor — adds £300-£500) vs weathered (small step)
- Colour: anthracite grey is 2026 UK default. Dual-colour (different inside/outside) adds £150-£300
- Structural work: removing a wall section adds £1,500-£5,000 — usually a separate quote from a structural engineer
Bi-fold vs sliding vs French doors
- Bi-fold: opens completely, folding panels stack to one side. Best indoor-outdoor experience. Downside — thicker frames visible when closed
- Sliding (patio): fewer, bigger panels. Slimmer sightlines when closed. Downside — one panel is fixed, so only 50-75% of the opening actually opens
- French: two traditional hinged doors. Cheapest, simplest. See our French doors cost guide
Hidden costs to budget for
- Structural work: if you’re creating the opening (not replacing existing doors), £1,500-£5,000 for an RSL steel beam + builders’ work
- Making good: floor threshold finish, internal plaster, external rendering — typically £400-£900
- Building Regs: notifiable structural work needs Building Control sign-off (your FENSA installer notifies for the door; the structural engineer handles the beam)
Planning permission
Rear bi-folds are usually permitted development on houses (not flats). Exceptions: listed buildings, conservation areas with Article 4 direction, properties in AONB or National Park. For openings creating a structural change, Building Regulations always apply.
Frequently asked questions
Is aluminium or uPVC bi-fold better?
Aluminium wins on frame slimness (more glass) and longevity (30-year frame life vs 20-25 for uPVC). uPVC wins on price and thermal performance (uPVC has naturally lower thermal conductivity than aluminium — which needs a thermal break to compete). If budget allows, aluminium is the UK default for a reason.
Do I need planning permission?
Usually no for rear bi-folds on houses — permitted development. Exceptions apply for listed buildings and conservation areas. Side or front bi-folds are more often restricted.
How long does bi-fold installation take?
1-2 days for the doors themselves once the opening is prepared. If structural work is needed (new opening), add 1-2 weeks for structural engineer specification, RSL delivery, and builder’s work. Typical total timeline: 6-10 weeks from order to completion.
Are bi-folds draughty?
Quality aluminium bi-folds with multi-point locking and properly installed thresholds are not draughty — u-values of 1.4-1.6 are standard. Cheap uPVC bi-folds with poor seals can be draughty, which is one of the reasons aluminium dominates the UK market despite costing more.
Get four bi-fold quotes
Compare 4 FENSA-registered installer quotes — free, no obligation. Bi-fold pricing has the widest spread of any glazing product; comparison routinely saves £1,500-£3,000.
Sources
- FENSA installer register
- UK aluminium bi-fold market data 2024-2025
- GOV.UK — permitted development rules
From homeowners like you
Really helpful comparing finance options — two of the four installers offered 0% APR. Picked the one with a 15-year frame warranty and the transparent breakdown.
Replaced 3 windows and the front door after our L-postcode terrace survey. The FENSA installer spotted a lintel issue the others missed and priced the proper fix in. Job done.
Quick, clear, no pressure. I asked the 6 questions from the buyer's guide and it genuinely filtered out the weaker installers. Picked the local one with the longest track record.