Aluminium bifold doors are folding glass panels on a top or bottom track that stack neatly to one or both sides, opening most of a wall to the garden. We make and fit Smart Visofold 1000 and Cortizo bifolds from our Fifield workshop near Windsor, with panels up to 1.2m wide, PAS 24 tested hardware and a 10-year guarantee.
![[HERO] Why Aluminium Bifold Doors Will Change the Way You Use Your Living Space](https://cdn.marblism.com/HKMy5z6cvlI.webp)
Get a free, fixed-price quote
Made in our own Fifield workshop and fitted by our own team. Aluminium windows from £400, lead times from 10 days and a 10-year guarantee. Tell us what you need and we’ll book a free survey.
This guide covers what a well-specified bifold looks like, the real sizes and limits of the two systems we use, glass and colour choices, security, what bifolds cost in 2026, and when a sliding door is the better buy. Everything technical here comes from the manufacturers’ own published data, linked at each point.
Which bifold systems do we fit?
We fabricate two aluminium bifold systems in our own workshop and install them with our own team. We do not fit Reynaers bifolds; our Reynaers products are the SlimLine 68 window and the ConceptPatio 130 sliding door.
- Smart Visofold 1000. Smart Systems describes it as the UK’s most popular bifold. It is a proven, well-supported system with a large choice of colours, thresholds and hardware, and it suits most extensions and garden rooms.
- Cortizo Bi-Fold System. A deeper 73mm profile from the Spanish extruder Cortizo. It takes taller sashes, thicker glass and heavier panels, and it can form a 90-degree open corner with no corner post. It is our usual choice for tall openings and corner sets.
Bifold spec table: Smart Visofold 1000 vs Cortizo
These figures are the manufacturers’ published maximums. Actual limits depend on the configuration, glass weight and opening, so we confirm them at survey.
| Feature | Smart Visofold 1000 | Cortizo Bi-Fold System |
|---|---|---|
| Maximum sash width | 1,200mm | 1,200mm |
| Maximum sash height | 2,500mm | 3,000mm |
| Maximum sash weight | 100kg (NBS listing) | 120kg (varies by layout) |
| Number of sashes | Made to order | 1 to 14 |
| Frame depth | 70mm to 82mm | 73mm |
| Typical sightline | 122mm | Not published as a figure |
| Glass unit thickness | 24mm to 38mm | 25mm to 45mm |
| Published U-value | 1.4 W/m²K | From 1.1 W/m²K |
| Thermal break | 30mm polyamide outer frame | 20mm frame, 30mm sash polyamide |
| Weather and wind | Tested to BS 6375-1 | Air class 4, water class 9A, wind class A3 |
| Security testing | PAS 24 approved hardware, BSI Kitemark | PAS 24:2012 certificate |
| Open corner option | Ask us | Yes, 90 degrees with no corner post |
Sources: Smart Systems Visofold 1000, NBS Source listing for Visofold and Cortizo Bi-Fold System.
Sizes, panels and layouts
A bifold is made of sashes up to 1.2m wide that fold in pairs. The number of panels you need comes from the width of the opening, and the layout comes from how you use the space.
- Two or three panels suit openings of roughly 1.8m to 3.5m, such as a replacement for old French doors or a small kitchen extension.
- Four to six panels suit most single-storey rear extensions, from around 3.5m to 6m.
- Seven or more panels, or a corner set, suit wide garden rooms. The Cortizo system allows up to 14 sashes and an open corner with no post.
Odd numbers of panels let you include a traffic door: one sash that opens like a normal hinged door so you can step outside in winter without folding the whole set. Panels can stack to the left, the right or split both ways. Most of our customers choose doors that fold outwards, because the stack then sits on the patio rather than in the room.
Height matters as much as width. The Visofold 1000 takes sashes up to 2.5m high, and the Cortizo system up to 3m. For a vaulted or extra-tall extension, Cortizo is usually the better fit.
Thresholds
Both systems offer a low threshold, so the floor inside and the patio outside can sit close to level. Smart also offers rebated outer frames and an integrated cill. A low threshold needs good drainage outside the door, such as a slot drain or a step down, which we plan at survey. For the most exposed openings a standard weathered threshold gives the best protection from driving rain.
Slimline aluminium bifold doors: what “slim” really means
Every bifold has a frame on each sash where the panels meet, so a five-panel door shows more aluminium than a two-panel slider of the same width. Smart publishes a typical sightline of 122mm for Visofold 1000; Cortizo describes its system as having a reduced sightline. Both are far slimmer than UPVC bifolds, which need thicker profiles for strength.
If an uninterrupted view matters more than opening the whole wall, look at a sliding door as well. Our Reynaers ConceptPatio 130 sliding doors use fewer, larger panes, and you can compare all our options on the patio doors page. As a rule of thumb, choose bifolds if you want the whole opening clear in summer, and a slider if you want the most glass all year round.
Glass options
Glass is most of a bifold’s area, so it drives its warmth, weight and noise. The Visofold 1000 takes sealed units from 24mm to 38mm thick, and the Cortizo system from 25mm to 45mm. Options we specify every week include:
- Low-emissivity coated double glazing with an argon gas fill and warm-edge spacer bars.
- Toughened safety glass as standard in doors, with laminated glass for extra security or noise reduction.
- Solar control glass for south and west-facing extensions that overheat.
- Self-cleaning coatings for tall or hard-to-reach panes.
- Integral blinds or obscure glass for privacy.
Triple glazing adds a lot of weight to each sash. Ask us whether triple glazing is available in your chosen system and sizes, and we will confirm it against the weight limits above. For more on glass ratings, see our energy-rated windows guide.
Building Regulations for thermal performance
In England, Approved Document L sets a limiting U-value of 1.4 W/m²K, or a Doorset Energy Rating of Band C, for replacement doors where more than 60% of the internal face is glazed (Approved Document L, Table 4.2). Smart publishes 1.4 W/m²K for Visofold 1000, and Cortizo publishes values from 1.1 W/m²K. Your actual figure depends on the glass and panel sizes, so we specify the glass to meet the rules for your door.
Colours and finishes
Our bifolds are polyester powder-coated, which is tough and easy to clean. Popular choices are anthracite grey, black, white and grey-blue tones, but any RAL colour can be specified. Smart offers matt, textured, metallic and wood-structure finishes, plus dual colour, so the inside can be white while the outside is dark grey.
We do not make timber doors. If you want a timber look, ask about a woodgrain-effect powder coat on aluminium. Handles come in black, silver, white and other finishes to suit the frame colour.
Security: PAS 24 and locking
PAS 24 is the British security test for doors and windows. It is the standard behind Approved Document Q, which sets security rules for new homes in England (BSI). Cortizo lists a PAS 24:2012 certificate for its bifold. Smart lists PAS 24 approved rollers and top guides for Visofold 1000, and the system carries a BSI Kitemark.
In practice our bifolds have:
- Multi-point locking on the main opening sash and shoot-bolts on the folding panels.
- Anti-snap, anti-bump cylinders.
- Internal glazing beads, so the glass cannot be removed from outside.
- Stainless steel rollers and heavy-duty hinges, with magnetic catches to hold panels in wind.
How much do aluminium bifold doors cost?
Bifolds are priced by opening size, number of panels, glass, colour and threshold, so every quote follows a survey. Our aluminium windows start from £400, but bifolds are a bigger product. As a market guide, MyJobQuote’s guide (updated September 2026) gives these supply and fit ranges for aluminium bifolds. These are market figures, not our prices.
| Panels | Opening width | Supply only | Supply and fit |
|---|---|---|---|
| 3 | 2.1m to 3.5m | £2,550 to £4,050 | £3,150 to £4,650 |
| 4 | 3.6m to 4m | £3,500 to £4,900 | £4,300 to £5,700 |
| 5 | 4.2m to 5m | £4,250 to £6,200 | £5,250 to £7,200 |
Source: MyJobQuote bifold door costs. The same guide puts fitting labour at about £600 to £1,000 depending on size. Prices rise for tall sashes, corner sets, dual colour, solar control or triple glazing, and structural work such as a new steel lintel. For wider budgeting, see our double glazing cost guide.
Do bifold doors need planning permission?
Replacing existing doors in a house with similar-looking ones is usually permitted development. You will normally need to check with your council if you live in a flat, a listed building, a conservation area or an area with an Article 4 direction, or if you are forming a new or wider opening as part of an extension. A new or widened opening also needs Building Regulations approval for the lintel. Our planning permission guide explains the rules in more detail.
How we survey, make and fit your bifolds
- Free survey. We measure the opening, check the lintel, floor levels and drainage, and talk through panel layout, glass and colour.
- Fixed quote. You get a written quote for the specification agreed.
- Fabrication in Fifield. We cut, assemble and glaze your doors in our own workshop near Windsor. Lead times start from 10 days, depending on colour and size; we confirm the date with your order.
- Installation by our own team. We remove the old doors, fit the frame square and level, set the threshold, adjust every panel and leave the opening sealed and finished.
- Guarantee. Our work is covered by a 10-year guarantee.
Looking after aluminium bifolds
Keep the bottom track clear of grit and leaves, and vacuum it every few weeks in autumn. Wash the frames with warm soapy water twice a year and avoid abrasive cleaners. Check the seals and give the locks and hinges a light spray of a silicone lubricant once a year. Smart publishes a guide to maintenance and care for its systems.
Related pages
- Aluminium windows and doors
- Reynaers aluminium sliding doors
- Patio doors
- Double glazing cost
- Areas we cover
Get a quote for aluminium bifold doors
Tell us the width of your opening and how you want the doors to fold, and we will book a free survey anywhere in Berkshire, Buckinghamshire and the Thames Valley. Call 01753 965 005, WhatsApp 07934 152 343, or request your free quote online. We are open Monday to Friday 8am to 6pm and Saturday 9am to 1pm.
Frequently asked questions
Which is better, Smart Visofold or Cortizo bifolds?
Neither is better for every home. Smart Visofold 1000 suits most openings up to 2.5m high and has a wide range of colours and thresholds. Cortizo takes taller sashes up to 3m, thicker glass up to 45mm and an open corner with no post. We recommend one after measuring your opening.
How wide can an aluminium bifold door be?
Each sash can be up to 1.2m wide in both systems, so overall width depends on the number of panels. Cortizo allows up to 14 sashes, which covers very wide garden rooms. Very wide openings need a strong lintel or steel, which we check at survey before confirming the layout.
Should bifold doors open inwards or outwards?
Most people choose outward-opening bifolds, because the folded stack sits on the patio and the room stays clear. Inward-opening doors suit balconies or patios with little space outside, and they sit more sheltered from the weather. We show you both options against your floor plan at survey.
Are slimline bifold doors the same as sliding doors?
No. Bifolds fold away to open almost the full width, but each panel has its own frame, so you see more aluminium. Sliding doors use fewer, larger panes and give a slimmer view, but one panel always stays in the opening. Choose bifolds for summer opening and sliders for year-round views.
Can I have a level threshold with bifold doors?
Yes, both systems offer a low threshold that brings the inside floor close to the patio level. It needs drainage outside, such as a slot drain or a small fall away from the door. On very exposed openings a weathered threshold gives better rain protection, and we advise on this at survey.
How long does it take to fit aluminium bifold doors?
Fitting usually takes one or two days, depending on the number of panels and any building work. Our lead times start from 10 days after order, depending on size and colour. We make your doors in our Fifield workshop and fit them with our own team, so we give you one date and keep to it.