London · Q2 2026
Bifold vs Sliding Doors
The honest, installer-side truth
Both products work. Both have a place. After 6,000+ projects across Richmond, Twickenham, Kingston, Chiswick, Putney, Wimbledon, Hammersmith and Fulham, the pattern is clear: bifolds win for opening-wide-and-entertaining; sliding wins for view-through-the-glass. If your door spends 80% of the year closed, you'll regret a bifold's chunky meeting stiles. If it spends 80% of the year open in summer, you'll regret a slider's partial opening.
Sightline comparison
When the doors are closed (most of the year, in London), the sightline determines what you actually see. Slim sliders dominate here.
| System | Type | Sightline | Visible glass (3m × 2.1m) |
|---|---|---|---|
| Cortizo Vision | Sliding | 20 mm interlock | ~88% |
| APX20 Plus | Sliding | 20 mm interlock | ~88% |
| Schüco ASE 60 RC | Sliding | 30 mm interlock | ~85% |
| APX47 | Sliding (large pane) | 45 mm interlock | ~80% |
| APX X-Fold 120 | Bifold | 120 mm meeting stile | ~70% |
| Schüco AS FD 75 | Bifold | 100 mm meeting stile | ~73% |
| Schüco AS FD 90 | Bifold premium | 90 mm meeting stile | ~75% |
| Visofold 1000 | Bifold | 110 mm meeting stile | ~71% |
Opening behaviour
Same 3m structural opening, totally different open-state experience. This is where bifolds reclaim ground sliders can't match.
| Configuration | Open span | Open behaviour |
|---|---|---|
| 3-pane sliding (1 fixed, 1 sliding) standard | ~50% | One pane slides behind one fixed |
| 3-pane sliding (2 fixed, 1 sliding) common | ~33% | One sliding pane in front of two fixed |
| 4-pane sliding (2-track) | ~50% | Two panes slide behind two fixed |
| Pocket slider (3-pane) | ~95% | Panes slide into wall cavity |
| 3-pane bifold | ~90% | Concertina-fold to one side |
| 5-pane bifold | ~92% | Concertina-fold (split or all one side) |
| 7-pane bifold | ~93% | Concertina-fold (typically split 3+4) |
| Lift-and-slide HS portal (Schüco ASE 80.HI) | ~50% | Heavy panes lift on rollers, slide silently |
Threshold options
A flush threshold is now standard-spec on most architect drawings. Both bifold and sliding offer it; the trade-off is weather rating.
| Threshold | Height | Weather rating | Available on |
|---|---|---|---|
| Standard raised (weather) | 55–70 mm | PA Class 9A | All bifold, all sliding |
| Low threshold | 35–45 mm | PA Class 7A | X-Fold 120, AS FD 75/90, APX20 Plus, Vision |
| Flush threshold (recessed track) | 15–25 mm | PA Class 6A | X-Fold 120, AS FD 75/90, Vision (hidden track) |
| Hidden track (in-screed) | 0 mm visible | PA Class 6A | Cortizo Vision, Schüco ASE 80.HI |
Real fitted prices — London Q2 2026
Indicative installed prices for typical 3m and 4m structural openings. Includes frame, double glazing, fitting, FENSA self-certification (Reg 40373) and 10-year installation guarantee. Triple glazing adds 20–25%; flush threshold adds £400–£900; hidden track adds £600–£1,200.
| Configuration | System | Low | High |
|---|---|---|---|
| 3-pane sliding (3m × 2.1m) | APX20 Plus | £4,500 | £7,500 |
| 3-pane sliding (3m × 2.1m) | Cortizo Vision | £5,500 | £9,000 |
| 3-pane sliding (3m × 2.1m) | Schüco ASE 60 | £6,500 | £10,500 |
| 3-pane bifold (3m × 2.1m) | APX X-Fold 120 | £6,000 | £9,500 |
| 3-pane bifold (3m × 2.1m) | Schüco AS FD 75 | £7,200 | £11,500 |
| 3-pane bifold (3m × 2.1m) | Schüco AS FD 90 | £8,500 | £13,000 |
| 4-pane sliding (4m × 2.4m) | APX20 Plus / Vision | £7,500 | £12,500 |
| 5-pane bifold (4m × 2.4m) | X-Fold 120 / AS FD 75 | £9,500 | £15,000 |
The verdict — when each wins
Use this as your decision shortcut. If you tick more rows on one side, that's your answer.
| When to choose Bifold | When to choose Sliding |
|---|---|
| You entertain outdoors weekly in summer | Doors stay closed 80%+ of the year |
| You need 90%+ open-span clearance | You want maximum visible glass when closed |
| Opening is over 6m wide (5+ panes) | Opening is 2–4m wide (sweet spot) |
| Indoor-outdoor living is the brief | Modern minimalist aesthetic is the brief |
| Garden views are short (under 7m depth) | Garden views are long or you want a clear sightline |
| Children/pets need wide unobstructed access | Acoustic isolation matters (sliders 38–42 dB) |
| Budget allows £8k+ comfortably | Budget is tight (slim sliding starts £4,500) |
| You don't mind 90–120mm meeting stiles | 20mm interlock is your priority |
Specifying the right system
For most London projects we end up recommending one of these five systems. Each is matched to a typical brief.
| Brief | Recommended | Why |
|---|---|---|
| Standard 3m garden bifold, value priority | APX X-Fold 120 | Best price-per-pane on a UK-fabricated bifold |
| Premium 4–5m bifold with thermal performance | Schüco AS FD 90 | 1.3 W/m²K, 90mm meeting stile, 20-year guarantee |
| Slim sliding doors, value priority | APX20 Plus | 20mm interlock at 15–20% lower cost than Vision |
| Architect-spec slim sliding | Cortizo Vision | 20mm interlock, 3000mm panes, hidden track option |
| Lift-and-slide for very heavy panes | Schüco ASE 80.HI | 0.84 W/m²K (triple), 450kg panes, 30mm interlock |
Frequently asked
Are bifold doors going out of style?
No, but the market has split. Bifolds remain dominant for narrower openings (under 4m) where you want to fully fold the entire span back. For wider openings on contemporary builds, the trend since 2022 has been toward slim sliding doors — Cortizo Vision, APX20 Plus — because the closed-state sightline is so much cleaner. Both are still being specified by London architects in 2026; bifolds are not dead, just no longer the default.
Do sliders open as much as bifolds?
No. A standard 3-pane sliding door opens roughly 2/3 of the span (one pane slides behind two fixed). A 3-pane bifold folds back to 95%+ of the span clear opening. The compromise is pocket sliders (slide into the wall cavity) which open 100%, or 4-pane lift-and-slide systems that can open one full half. If full-span opening is non-negotiable, bifold still wins.
Which is more thermally efficient — bifold or sliding?
Sliding doors typically achieve 1.3–1.0 W/m²K whole-door U-value with double glazing. Bifolds typically achieve 1.4–1.6 W/m²K. The difference comes from the meeting stiles — every bifold pane has two stiles meeting another pane, doubling the thermal break complexity. Schüco AS FD 90 closes the gap at 1.3 W/m²K, but slim sliders like Cortizo Vision (1.3 W/m²K) and Schüco ASE 80.HI (0.84 W/m²K with triple glazing) lead overall.
Which is cheaper — bifold or sliding doors?
Sliding doors usually win on price for the same opening width. A 3m × 2.1m 3-pane sliding door fits at £4,500–£9,000 (APX20 Plus) vs £6,000–£12,000 for a 3-pane bifold (X-Fold 120, Schüco AS FD 75). Sliders have fewer moving parts, fewer hinges, and simpler hardware. Bifolds get more expensive faster as panes are added because every additional pane adds two hinges and a meeting stile.
What are the sightlines on a bifold vs sliding door?
Bifold meeting stiles are typically 90–120mm wide where two panes meet (45–60mm per pane × 2). Sliding door interlocks range from 20mm (Cortizo Vision, APX20 Plus) to 50mm (standard slider). Visually, that's the difference between a window-like view and a clearly framed view. For maximum visible glass when closed, sliding wins by a large margin.
Can bifolds have a flush threshold?
Yes. APX X-Fold 120, Schüco AS FD 75, and Visofold 1000 all offer a low-threshold or flush-threshold option that drops the rail to 22–35mm above floor level — wheelchair-friendly and visually seamless. The trade-off is reduced weather resistance: flush thresholds are typically rated to lower water-tightness classes than the standard raised threshold (PA Class 9A vs Class 6A).
How wide can sliding and bifold doors go?
Bifolds can run almost indefinitely — 7-pane configurations spanning 7m+ are common, limited mainly by the structural opening rather than the door. Sliding doors are usually capped at 4-pane straight runs (around 6m) or larger if pocket-sliding (slides into the wall). For openings over 6m, bifold and pocket-slide are the two practical options.
Which is more secure — bifold or sliding?
Both can meet PAS 24:2022 with multi-point locking. Sliding doors with hook-bolt mechanisms (Cortizo Vision, Schüco ASE 60 RC) are arguably harder to force because there's only one moving pane to compromise; bifolds have a master door and slave panes, with the master being the key entry point. In practice, both are very secure and home insurance treats them equivalently.
Bifold or sliding for a small London garden?
For typical London terrace/semi gardens (3–4m opening, under 7m garden depth), slim sliding doors usually look better year-round — the 20mm interlock keeps the view clean even in winter when doors stay closed. Choose bifolds if you genuinely entertain outdoors weekly in summer and need full-span opening; choose sliding if the door is closed 80%+ of the year and the view matters more than the opening.
