Anthracite Grey Cortizo Aluminium 4-Panel Bifold Door
RAL 7016 powder-coated frame. From £2,660 · 14 working day lead time · Free delivery over £1,450 · 28mm toughened Low-E glass.
Sizes: 2,800–4,000mm wide × 1,900–2,400mm tall.
Price range: £2,660 (smallest) to £2,900 (largest popular size).
Configure size & opening pattern →About Anthracite Grey Cortizo aluminium bifolds
Anthracite Grey (RAL 7016) is the dominant UK colour for Cortizo aluminium bifolds since 2024. The mid-grey tone reads as contemporary without going as stark as black, and it hides road dust and pollen far better than white — particularly relevant for south-facing or coastal openings. Anthracite suits red brick, painted render, slate-effect cladding, and timber decking equally well, which is why most architects spec it by default for kitchen rear extensions and garden rooms. The powder-coated finish carries a 25-year guarantee against the colour fading or chalking.
This panel count. 4-panel anthracite grey bifolds suit openings of 2,800–4,000mm wide. Most common in larger rear extensions or wider knock-throughs. Pricing: from £2,660 at the smallest popular size up to £2,900 at the largest. No VAT to add.
Anthracite Grey pairs well with
- Red brick
- Painted render (Farrow & Ball Cornforth, Mizzle, or Down Pipe)
- Slate-effect cladding
- Light oak or grey-stained timber
- Polished concrete floor
- Composite cladding (Cedral, Marley)
Other 4-panel colours
Same panel count, different frame colour. All on a 14-day lead time, no price uplift.
Black 4-Panel
Cortizo aluminium vs uPVC vs sliding doors
| Cortizo Aluminium 4-Panel | uPVC 4-Panel | Aluminium Sliding Door | |
|---|---|---|---|
| Frame depth (sightline) | ~50mm slim | ~70–90mm bulky | ~30mm ultra-slim |
| Maximum opening | Up to 4,000mm wide | Up to 4,000mm wide | Up to 6,000mm+ |
| Frame stiffness | High (no reinforcement bars needed) | Lower (mullion bars on wider spans) | High |
| Folds away when open | Yes — full opening | Yes — full opening | No (door slides behind fixed pane) |
| Glass area when closed | ~80% | ~65% | ~85% |
| Colour options (stocked) | Black, White, Anthracite Grey (14-day) | White, Anthracite Grey foil (3–4 weeks) | Black, Anthracite, RAL custom |
| Thermal U-value | ~1.4 W/m²K | ~1.4 W/m²K | ~1.5 W/m²K |
| Typical UK price (this size) | From £2,660 | From £1,995 | From £3,724 |
| Best use | Kitchen extension, garden room, rear elevation | Budget-conscious openings up to 4m | Wide patios where full opening isn't needed |
Cortizo aluminium suits most bifold projects above 2.4m wide. For narrower openings, uPVC is a sensible budget choice; for very wide openings (5m+) a sliding door is more practical.
Building Regulations & compliance
Part L (thermal performance) — Cortizo aluminium bifolds use a polyamide thermal break + 28mm argon-filled Low-E sealed glazing. Whole-door U-value typically ~1.4 W/m²K, comfortably below the 1.6 maximum for replacement doors.
Part Q (security in new dwellings) — multi-point locking on the lead leaf with anti-lift hooks meets the security spec for doors in new-build dwellings (PAS 24 equivalent on the locking hardware). Replacement installations don't require Part Q but get the same security standard by default.
Part M (access) — standard threshold has a rebated profile with sill (~25mm step). For wheelchair access or step-free thresholds (Part M-compliant), submit a custom quote — we can specify a low-threshold variant (different from the stocked configuration).
Part K (glazing safety) — every leaf is fitted with 28mm toughened double-glazed unit (4mm tough outer + 20mm cavity + 4mm tough inner with low-E coat). Toughened both panes by default because doors and side panels are critical locations under Part K.
How to install (5-step summary)
- Confirm the opening — plumb, level, with an adequate lintel above. Confirm with your installer or structural engineer before ordering.
- Order to your exact size — use the configurator at /bifold-doors.html. We make to your measurements; deduct nothing for tolerance.
- Prepare for delivery — ground-floor access, 2–3 person unload. Doors arrive crated.
- Fit the frame — packers, fixings (5 per side), external silicone. Frame must sit perfectly square.
- Hang and adjust — fit the gear, run the doors, adjust rollers and hinges. Allow 1–2 days for the full job.
FAQs
Why is Anthracite Grey the most popular colour for Cortizo aluminium bifold doors?
Anthracite Grey (RAL 7016) sits between black and silver — modern enough for new-build extensions but soft enough not to dominate the elevation. It hides road dust, pollen and rain marks far better than white, which matters for south-facing or coastal openings. Most UK architects spec it by default for kitchen rear extensions in 2025-2026, which is why it's our highest-volume stocked colour. The powder-coat carries a 25-year colour-fade guarantee.
Does Anthracite Grey fade or chalk in UK weather?
Cortizo's powder-coated finish is qualicoat-class accredited and warranted for 25 years against fading, chalking, blistering, or peeling. Real-world performance is significantly better — properly cleaned anthracite frames installed in the 1990s still look near-original today. Wash with warm soapy water 2-4 times a year (more if coastal); avoid abrasive cleaners.
How much does a 4-panel Cortizo aluminium bifold door cost?
From £2,660 for the smallest popular size (2800×1900mm) up to £2,900 for the largest (4000×2400mm). Use the configurator at /bifold-doors.html to see your exact price for any size in this range. Price includes 28mm toughened Low-E glass, standard threshold with sill, your choice of Black, White or Anthracite Grey powder-coated frame, and multi-point locking.
What sizes can I order for a 4-panel bifold?
Popular range is 2800–4000mm wide × 1900–2400mm tall. Outside this range we still make them — submit a custom quote at /custom-quote.html and we reply within one working day. Above 5,000mm wide or 2,400mm tall typically needs corner support or a structural engineer's input.
What's the lead time and is delivery included?
14 working days from order confirmation to delivery. Free delivery to mainland England and Wales when the order is over £1,450 (which a 4-panel bifold always is). Highland Scotland, Northern Ireland, Isle of Wight and remote postcodes need a delivery quote — call 0800 861 1450.
What configurations are available for 4 panels?
4-panel bifolds come in four opening configurations: 4L (all left, with traffic door), 3L+1R, 2L+2R (meet in the middle), or 4R (all right). The 2L+2R "meet in the middle" pattern is most popular for symmetrical openings.
Do I need a structural lintel above a 4-panel bifold?
Yes. Bifold doors need an adequate load-bearing lintel or steel above the opening to take the wall above. Your installer or a structural engineer should size this based on the wall construction. We supply the doors only and don't specify or supply lintels. The opening also needs to be plumb, level, and structurally supported before the door arrives.
Do you install bifold doors?
No, we are supply only. Bifold installation is specialised — a competent fitter will need to confirm the opening is plumb, level and properly supported above. We can recommend a local fitter in the London and Home Counties area if you need one. Allow roughly 1–2 days for installation depending on opening complexity.
Anthracite Grey 3-Panel
Anthracite Grey 5-Panel