Bifold Door Installation Cost 2024: Supply & Fit Guide UK

Quick Answer: Aluminium bifold doors run £1,200–£2,400 per linear metre supply trade, £550–£950 per day labour for a 2-fitter team. A typical 3-metre 3-panel bifold installation totals £4,500–£8,500 finished including structural opening, threshold and lintel. All installations must meet Building Regulations Part L 2021 (U-value ≤1.4 W/m²K) and Part Q for new builds.

Summary

Bifold and sliding door installations are some of the most lucrative jobs available to glazing trades. A correctly priced 3-panel bifold quote returns £2,000–£3,500 gross margin; a badly priced one loses money on the threshold detail alone. The gap between profit and loss is in the structural opening, the threshold finish, and the make-good — none of which appear on the door fabricator's quote.

Bifolds work on a folding-track system (panels fold and stack at one or both ends). Sliders use a lift-and-slide or sliding-only mechanism (panels overlap, no folding). Both have shifted from premium-only to mainstream over the last decade — clients now expect 3-metre+ openings and slim sightlines as standard. Aluminium dominates (around 90% of installations), with timber-clad and full-timber commanding higher margins in heritage and architect-led work.

This guide covers all three system types, the structural and threshold detail that determines real cost, the FENSA/CERTASS compliance route, and a worked example for a 3-metre 3-panel install. Quote at 25–35% margin minimum — the risk profile justifies it.

Key Facts

Quick Reference Table

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System Opening Size Supply Trade Fit Labour Structural Threshold Total Indicative
Bifold 2-panel (1.8m) 1,800 × 2,100 £2,400–£3,800 £550–£800 £450–£900 £150–£350 £3,550–£5,850
Bifold 3-panel (2.7m) 2,700 × 2,100 £3,500–£5,800 £750–£1,100 £600–£1,200 £250–£500 £5,100–£8,600
Bifold 4-panel (3.6m) 3,600 × 2,100 £4,800–£7,800 £900–£1,400 £800–£1,600 £300–£600 £6,800–£11,400
Bifold 5-panel (4.5m) 4,500 × 2,300 £6,200–£9,800 £1,100–£1,700 £1,000–£2,200 £350–£700 £8,650–£14,400
Bifold 6-panel (5.4m) 5,400 × 2,300 £7,800–£12,400 £1,400–£2,200 £1,400–£3,200 £400–£900 £11,000–£18,700
Slider 2-panel (2.4m) 2,400 × 2,100 £2,800–£4,400 £550–£900 £500–£1,000 £250–£500 £4,100–£6,800
Slider 3-panel (3.6m) 3,600 × 2,400 £4,900–£7,800 £900–£1,400 £800–£1,800 £350–£700 £6,950–£11,700
Lift-and-slide premium (3m) 3,000 × 2,400 £5,800–£9,200 £1,100–£1,700 £700–£1,500 £400–£800 £8,000–£13,200

Detailed Guidance

Bifold vs slider — choosing for the client

Bifolds give 90%+ open aperture but stack inside or outside, eating wall or patio space. Sliders give 50% open aperture max (one panel slides behind another), but no panel intrusion. Lift-and-slide gives best weather seal and runs heaviest panels (up to 600kg+).

Clients often want bifolds for "indoor-outdoor" feel but live in cold/rainy areas. Suggest slider if the door faces prevailing wind — bifold gaskets are weakest at corners and let water in driving rain. Suggest bifold if entertaining and full opening matter more than weather sealing.

Quote bifolds with even panel count for traffic doors (3, 5, 7 — one panel acts as standalone access). Odd panel count with no traffic door is cheaper but client must open all panels every time.

Structural opening — the biggest variable

If the door replaces an existing matching-sized opening (like-for-like) the structural cost is minimal — just timber/steel lintel above. If it replaces a smaller window or door, or removes part of a load-bearing wall, you need:

  1. Structural engineer report — £350–£900 specifying beam size and bearing length. Mandatory before any wall opening.
  2. Building Control approval — Either via approved inspector (£500–£900) or Local Authority (£450–£800). Cannot self-certify structural work.
  3. Beam supply — Domestic 3m opening typically 178×102 UB or 203×133 UB. £200–£500 supply.
  4. Acro propping — Strongboy or Acro props during cut. £50–£100 hire.
  5. Beam fit labour — 1 day for 2 builders cutting, propping, inserting, dropping props. £300–£600.
  6. Pad stones — Concrete or engineering brick pad stones each end. £40–£100.
  7. Make-good — Brickwork, plaster, plinth detail. £400–£900 typically.

Build structural as a separate line on the quote: "Open structural reveal (subject to engineer's spec): £X,XXX." Do not absorb structural risk into the door price.

Threshold detail — the most-disputed line item

Threshold options sit between weather performance and aesthetic. Pricing varies hugely:

Flush thresholds are the source of 80% of bifold complaints. Quote them carefully, specify drainage, and warn client about driving rain ingress risk. Don't promise weatherproof; specify the system's certified weather rating (Class 9A under BS EN 12208 = best class).

Glazing options and upgrades

Standard spec is double-glazed argon-filled 4-16-4, Low-E coating, achieving 1.4 W/m²K. Common upgrades:

Always quote toughened or laminated for the door — clients sometimes ask for "just standard glass to save money" — refuse, it's non-compliant.

Hardware and finish

Aluminium colour is the largest finish cost driver:

Handle quality matters — D-pull, slimline, or full-height pull handles range £40–£250 per door. Don't include "premium handles" unless quoted; clients selecting from a brochure often pick top spec without realising the cost.

Lead times and deposit terms

Bifold supply lead times are 4–8 weeks for mainstream aluminium (Origin, Smart Systems, Liniar), 6–10 weeks for Schueco/Reynaers/premium, 8–12 weeks for full bespoke or unusual sizes/colours.

Deposit structure:

Add commencement clause: "Structural opening, scaffolding/access and clear working area to be ready on date X. Late readiness incurs storage/return-visit fee £200/day."

Worked example — 3-panel aluminium bifold, 2.7m × 2.1m, replacing patio door

Frequently Asked Questions

Do bifolds need a steel lintel?

Only if you're widening or creating an opening. Replacing a like-for-like existing door opening uses whatever lintel is already in place — inspect it for rust, sag or rot before installing. Concrete lintels generally fine; old timber lintels often need replacement. New openings or widenings always need engineer-spec steel; never guess RSJ size.

What's the maximum bifold size for a domestic install?

Aluminium systems max out at 7–8 metres / 6–7 panels for residential. Beyond this, weight, sag, and weather sealing become problematic, and you're into commercial systems. Practical residential max is 5–6 metres / 5–6 panels. Above 4 metres, two structural openings often work better than one giant span — cheaper, safer, less wind-loading.

Are bifolds secure?

Modern aluminium bifolds meet PAS 24:2022 if specified — they have multi-point shootbolts, anti-snap cylinders, and security hinge pins. Cheaper imported systems often don't meet PAS 24 — check the certification before quoting. New-build dwellings require Part Q-compliant doorsets (PAS 24); replacement in existing dwellings can use non-PAS-24 but it's poor practice.

Can I install a bifold without involving Building Control?

Yes if you're FENSA or CERTASS registered AND the structural opening doesn't change. If structural opening changes (new beam, wider opening) you must notify Building Control separately for the structural element — FENSA/CERTASS only covers the glazing.

How long does install take?

A 3-panel like-for-like bifold replacement: 1 day for 2 fitters including threshold. A new opening with structural work: 2–3 days minimum (1 day structural, 1 day door install, ½ day make-good). Allow 1 week elapsed time for new-opening jobs to allow plaster and silicone to cure before final inspection.

Regulations & Standards