Cortizo makes four sliding doors that we fabricate in Slough. COR Vision has the slimmest 20mm interlock and panels to 2.5 × 3m. COR Vision Evolution adds triple glazing, 500kg panels to 3.5 × 3.5m and the best U-value of the range at 0.88 W/m²K. COR Vision Plus is the largest format, with 4 × 4m panels and glazing up to 56mm. The Cortizo 4700 is the sturdier, more traditional choice, with a 47mm interlock.
We fabricate Cortizo at our own factory in Slough, so the figures below are not marketing copy — they are Cortizo’s published system data, checked against what we cut, machine and glaze. The four systems are not a good/better/best ladder: each one wins on something.
The four systems at a glance
| System | Choose it for | Key numbers |
|---|---|---|
| COR Vision | The slimmest possible view | 20mm interlock · panels to 2.5 × 3m · double glazing |
| COR Vision Evolution | Triple glazing and big, heavy panels | 25mm interlock · panels to 3.5 × 3.5m at 500kg · Uw from 0.88 · corners that open fully |
| COR Vision Plus | The very biggest openings | 25mm interlock · panels to 4 × 4m · glazing up to 56mm · motorised to 700kg |
| Cortizo 4700 | A sturdier, more traditional frame | 47mm interlock · panels to 2.5 × 3m · double glazing to 36mm · Uw from 1.0 |
What do Cortizo sliding doors cost?
Our COR Vision sliding doors start from £4,000 + VAT, supplied and fitted, for a 2-panel door 2.0m wide and 2.15m high. A 3-panel COR Vision door 3.0m wide starts from £5,400 + VAT. COR Vision Evolution, COR Vision Plus and the Cortizo 4700 are priced on request, because size, panel count, glass and colour move the price more than the system does.
Full specification comparison
| Specification | COR Vision | COR Vision Evolution | COR Vision Plus | Cortizo 4700 |
|---|---|---|---|---|
| Sightline where panels meet | 20mm | 25mm | 25mm | 47mm |
| Frame depth, 2-track | 116mm | 160mm | 180mm | 115–120mm |
| Frame depth, 3-track | 182mm | 248mm | 278mm | 185mm |
| Maximum panel size | 2500 × 3000mm | 3500 × 3500mm | 4000 × 4000mm | 2500 × 3000mm |
| Maximum panel weight | 320kg | 500kg | 400kg manual / 700kg motorised | 280kg |
| Glazing thickness | 28–30mm (double) | 28–44mm (double or triple) | Up to 56mm (double or triple) | 26–36mm (double) |
| Panels | Up to 8, on up to 4 tracks (8 panels exclusive to DTW) | 1 to 8, on up to 4 tracks | 2, 3, 4 or 6 | 2, 3, 4 or 6 |
| Thermal transmittance | Uw from 1.3 W/m²K | Uw from 0.88 W/m²K | Uw from 0.9 W/m²K | Uw from 1.0 W/m²K |
| Acoustic performance | Rw to 41dB | Rw to 43dB | Rw to 43dB | Rw to 40dB |
| Air permeability (EN 12207) | Class 4 | Class 4 | Class 4 | Class 3 |
| Watertightness (EN 12208) | Class 7A | Class E900 | Class 7A / 9A | Class 7A |
| Wind resistance (EN 12210) | Class C5 | Class C3 | Class C3 / C4 | Class C5 |
| Visible sash / lateral sightline | 37mm | 62mm | 69mm | – |
| 90° corner that opens fully (the corner post slides with a panel) | Yes — inner and outer | Yes — inner and outer | Yes | No |
| Pocket (into-the-wall) version | Yes, 1–6 sashes | Yes | Yes, 1–4 sashes | Yes, 1–4 sashes |
Every figure is from Cortizo’s published technical files (COR Vision, Evolution, Vision Plus, 4700). One thing worth flagging: the weather classes were not all earned on the same size of test specimen — COR Vision’s C5 wind class comes from a 1.23 × 1.55m reference test and the 4700’s from a 1.8 × 2.2m one — so ask for the classification at your sizes rather than comparing headline classes across systems.
How each layout slides, seen from above
A sliding door is a set of glass panels on parallel tracks. Fixed panels stay put; sliding panels run on their own track and park in front of the panel they pass. More tracks let more panels stack, so a bigger share of the opening clears: triple track sliding doors open two-thirds of the width, and 4 panel sliding doors on four tracks open three-quarters. The plans below show the common layouts, looking down from above with the garden at the top.
Which system can do which layout, using each system’s panel counts:
| Layout | COR Vision | COR Vision Evolution | COR Vision Plus | Cortizo 4700 |
|---|---|---|---|---|
| 2 panels | ✓ | ✓ | ✓ | ✓ |
| 3 panels on 3 tracks | ✓ | ✓ | ✓ | ✓ |
| 4 panels on 4 tracks | ✓ | ✓ | ✓ | ✓ |
| 4 panels, opening in the middle | ✓ | ✓ | ✓ | ✓ |
| 6 panels on 3 tracks | ✓ | ✓ | ✓ | ✓ |
| 90° corner that opens fully | ✓ | ✓ | ✓ | – |
| Pocket sliding door | ✓ | ✓ | ✓ | ✓ |
Which one should you choose?
| Your situation | System | Why |
|---|---|---|
| Slimmest possible view, panels within 2.5 × 3m | COR Vision | The 20mm interlock is at the slim end of the whole market |
| Retrofit into a shallow reveal | COR Vision or 4700 | A 116mm or 115–120mm frame hides where 160mm or 180mm will not |
| Panels up to 3.5 × 3.5m | COR Vision Evolution | 500kg sashes without motorisation |
| Best U-value / triple glazing to 44mm | COR Vision Evolution | Uw from 0.88 W/m²K — the best of the four |
| A corner that opens fully | COR Vision, Evolution or Plus | On all three the corner post slides away with a panel — panel size and weight decide which. The 4700 needs a fixed corner post |
| Panels beyond 3.5m, or glazing beyond 44mm | COR Vision Plus | To 4 × 4m, 56mm units, 700kg motorised |
| A sturdier, more traditional look | Cortizo 4700 | A 47mm interlock on a robust frame, in 2, 3, 4 or 6 panels |
| Exposed / high-wind site | Check per system | COR Vision and the 4700 hold C5, Evolution C3, Plus C3/C4 — but test specimen sizes differ, so ask for the class at your sizes |
If a supplier answers “whichever you prefer” to those questions, they are selling you a brochure. The opening decides, not taste.
Where does COR Vision Evolution fit?
Evolution is Cortizo’s newest slider and sits between COR Vision and Plus: the same slim 25mm interlock as Plus, triple glazing up to 44mm, 500kg panels to 3.5 × 3.5m and the best U-value of the range. Within its size ceiling it typically comes in below Plus on cost. See the COR Vision Evolution sliding door page for its full specification.
Where does the Cortizo 4700 fit?
The 4700 is the conventional one of the four: a sturdier frame with a wider 47mm interlock instead of a minimal one. It takes double glazing up to 36mm, panels to 2.5 × 3m and 280kg, and reaches Uw 1.0 W/m²K. Choose it when the house suits a more traditional frame, or when you want a robust sliding patio door rather than a minimal glass wall. At a corner it needs a fixed post. See the Cortizo 4700 sliding door page.
What is the interlock, and does 5mm matter?
The interlock is the aluminium you see where two sliding panels overlap in the middle of the opening — 20mm on COR Vision, 25mm on Evolution and Plus, and 47mm on the 4700. On a well-detailed opening the outer frame is buried in the structure, so the interlock is most of what you actually see. Across a six-panel run the 5mm difference between COR Vision and Plus repeats at every junction and adds up to 15mm.
Corner sliding doors that open completely
COR Vision, Evolution and Plus can all open a 90-degree corner completely. There is a slim corner post, but it is fixed to one of the corner panels rather than to the frame, so it slides away with that panel and leaves the corner clear. Many UK comparison pages still claim the base COR Vision cannot do this — Cortizo’s current technical file says it can, in both inner and outer configurations. The 4700 needs a fixed corner post. The panel sizes and weights at the corner decide which system the drawing calls for, and the structure above must be carried without the corner helping.
The biggest openings
For a wall of glass more than 3.5m per panel, COR Vision Plus is the system the drawing usually calls for: panels to 4 × 4m, glazing up to 56mm, and motorised operation for panels up to 700kg.
Why buy from the fabricator?
Most companies selling these systems are resellers. We fabricate Cortizo in Slough, so a survey correction is a works instruction rather than a change order to a third party — and the specification advice is unfiltered: we will tell you when the smaller, cheaper system is the right answer, because we gain nothing by selling the bigger one. Every door comes with a 10-year warranty. Direct Trade Windows is Constructionline Gold and FENSA registered, rated 4.9 on Google, with work published in Dezeen.
Where we install Cortizo sliding doors
We make our sliding doors in Slough and install them across London, the Home Counties and the rest of the UK. Some of the areas we work in most:
Wandsworth and Wimbledon (SW18, SW19, SW20)
Mostly side-return and rear extensions on Victorian and Edwardian villas.
Esher, Cobham, Walton and Weybridge (KT11, KT12, KT13)
The Surrey private estates, mostly through developers and architects on knock-down-rebuild plots — including the glazed pavilion in Hersham (KT12) photographed at the top of this page, with COR Vision sliding walls wrapping its corner. Estate hours-of-restriction, gate protocols and vehicle-access rules are routine for our install teams.
East Finchley, Finchley and Whetstone (N2, N3, N20)
Inter-war and Edwardian family houses. In N2, Hampstead Garden Suburb properties need Trust consent as well as council planning — two separate processes.
Berkhamsted and the Chilterns (HP1, HP4, HP6, HP7)
In Berkhamsted’s conservation-controlled centre, the rear elevation is usually where modern glazing is allowed to happen.
Slough and Maidenhead (SL1, SL6)
The factory’s own doorstep, including the Fisheries Estate riverside pocket at Bray.
Tunbridge Wells and the South East
Including the kitchen opening below, where COR Vision panels run from the kitchen straight out to the garden.
Hove (BN3)
Regency and Victorian stock — and a coastal site is a good reason to check the wind and watertightness rows in the table above.
Where to go next
Full specifications and finishes are on each system’s own page: Cortizo COR Vision, COR Vision Evolution, COR Vision Plus and the Cortizo 4700. The aluminium sliding doors page sets all four side by side, with their cross-sections.
Send us the opening, not the product name
Give us the structural opening size, the reveal depth and whether a corner is involved, and we will tell you which Cortizo system the drawing actually calls for — including when it is the smaller one.
