London · Q2 2026
Slimline Sliding Doors in
London.
What makes a sliding door slimline
The interlock is the vertical bar where two sliding panes meet. On a standard aluminium slider it sits at 50–60mm. On uPVC it's 100mm+. Slimline systems shrink it to 20–35mm — almost doubling the visible glass-to-frame ratio. Same opening, more view.
| System | Interlock | U-Value | Max pane | Max weight |
|---|---|---|---|---|
| Cortizo Cor Vision | 20 mm | 1.3 W/m²K | 3000 × 2200mm | 320 kg |
| APX20 Plus | 20 mm | 1.3 W/m²K | 2700 × 2000mm | 280 kg |
| Schüco ASE 60 RC | 30 mm | 1.0 W/m²K | 3000 × 2700mm | 400 kg |
| Schüco ASE 80.HI | 35 mm | 0.84 W/m²K | 3000 × 3000mm | 450 kg |
| APX47 | 45 mm | 1.2 W/m²K | 3500 × 1800mm | 400 kg |
Slimline sliding door prices
Fitted prices for slimline aluminium sliding doors, London, Q2 2026. All prices include VAT, frame, double glazing, fitting, disposal of old door, and FENSA self-certification. Triple glazing adds 20–25%. Hidden floor track adds £600–£1,200 per opening.
| Configuration | System | Low | High |
|---|---|---|---|
| 2-pane (1 fixed, 1 sliding) | APX20 Plus | £4,500 | £6,500 |
| 2-pane (1 fixed, 1 sliding) | Cortizo Vision | £5,500 | £7,500 |
| 3-pane (2 fixed, 1 sliding) | APX20 Plus | £6,000 | £9,000 |
| 3-pane (2 fixed, 1 sliding) | Cortizo Vision | £7,200 | £10,800 |
| 4-pane straight | APX20 Plus / Vision | £8,500 | £12,500 |
| 4-pane corner (90° structural) | Cortizo Vision | £10,500 | £14,000+ |
| 3-pane pocket (slides into wall) | Cortizo Vision | £9,500 | £13,500 |
| Lift-and-slide HS portal | Schüco ASE 80.HI | £9,000 | £16,000+ |
APX20 Plus vs Cortizo Vision
Both systems hit the 20mm interlock benchmark. The choice usually comes down to budget, pane height, and whether you want a hidden floor track. Honest breakdown:
| Spec | APX20 Plus | Cortizo Vision |
|---|---|---|
| Interlock | 20 mm | 20 mm |
| U-value (double-glazed) | 1.3 W/m²K | 1.3 W/m²K |
| Max pane height | 2700 mm | 3000 mm |
| Max pane weight | 280 kg | 320 kg |
| Hidden floor track option | No | Yes |
| Acoustic rating | 38 dB | 42 dB |
| Security | PAS 24 | PAS 24 |
| Powder-coat colours | Standard RAL | Full RAL + dual colour |
| Typical fitted price (3-pane) | £6,000–9,000 | £7,200–10,800 |
When to specify slimline over standard
Slimline sliders carry a 20–40% premium over standard 50mm-interlock systems. Worth it in these scenarios; overkill outside them.
| Scenario | Why slimline matters | Recommended |
|---|---|---|
| Rear extension with garden view | Interlock at eye level dominates the sightline. 20mm vs 60mm is the difference between a frame and a window. | Cortizo Vision |
| Architect-designed contemporary build | Specified almost universally. Anything thicker undermines the brief. | Cortizo Vision / APX20 Plus |
| Tight budget contemporary look | APX20 Plus delivers identical 20mm sightline at lower cost. | APX20 Plus |
| Single-pane runs over 2.7m tall | Standard 20mm systems max out at 2700mm; Vision goes to 3000mm. | Cortizo Vision |
| 4+ pane corner installations | Corner posts are visually heaviest part — slimline minimises them. | Cortizo Vision |
| Standard suburban patio replacement | 20mm vs 50mm rarely visible in a 2-pane unit. Save the money. | APX35 / standard slider |
| Listed / front elevation conservation | Slimline aluminium not approved on heritage frontages — use timber. | Timber sliding sash |
What's actually included
A fitted slimline sliding door from Apex Glazing always includes:
| Site survey and structural opening check (free) |
| Frame, sashes, and double glazing (laminated security glass standard) |
| Multi-point hook locks and PAS 24 cylinder |
| Powder-coated finish in any RAL colour (matt, satin, or textured) |
| Removal and disposal of old door |
| Trickle vents and Document Q air-flow compliance |
| Internal and external silicone seal, threshold trims |
| FENSA self-certification (Reg 40373) — registered with your local authority |
| 10-year guarantee on frame and hardware, 5 years on sealed units |
Frequently asked
What is a slimline sliding door?
A slimline sliding door is an aluminium patio door with a vertical interlock (the bar where panes meet) of 20–35mm, compared to 50–100mm on standard sliding doors. The slimmer the interlock, the more glass and less frame you see — important for clean modern aesthetics and unobstructed garden views. Cortizo Vision at 20mm is currently the slimmest available in the UK as of 2026.
How much do slimline sliding doors cost in London?
Fitted slimline sliding doors in London cost £4,500–£6,500 for a 2-pane configuration, £6,000–£9,000 for 3-pane, and £9,000–£14,000+ for 4-pane corner or pocket configurations in 2026. Prices include VAT, frame, double glazing, fitting, and FENSA self-certification. Cortizo Vision at the 20mm sightline carries a 15–20% premium over APX20 Plus.
What is the slimmest sliding door interlock in the UK?
Cortizo Cor Vision at 20mm is the slimmest sliding door interlock available in the UK as of 2026. APX20 Plus matches at 20mm. Schüco ASE 60 RC sits at 30mm. Most standard aluminium sliders are 50–60mm interlock, and uPVC sliders are typically 100mm+.
Are slimline sliding doors thermally efficient?
Yes. Cortizo Vision and APX20 Plus achieve 1.3 W/m²K whole-door U-value with double glazing, dropping to 0.9 W/m²K with triple glazing. That is comparable to standard aluminium casement windows and better than most uPVC patio doors. The slimmer profile doesn't compromise thermal performance because the polyamide thermal break runs through the full frame depth.
How big can slimline sliding door panes be?
Cortizo Vision panes can be up to 3000mm tall at 320kg per pane. APX20 Plus tops out at 2700mm. APX47 (45mm interlock, large-pane specialist) handles up to 3500mm × 1800mm at 400kg per pane. Schüco ASE 80.HI is rated for up to 3000mm × 3000mm panes at 450kg. Pane size depends on glass spec, wind exposure, and structural opening width.
Can slimline sliding doors meet PAS 24 security?
Yes. Cortizo Vision, APX20 Plus, and Schüco ASE all carry PAS 24:2022 certification with multi-point hook locks and laminated security glass. Schüco ASE 60 RC additionally meets RC2 (Resistance Class 2) per EN 1627, the police-preferred Secured by Design standard.
Slimline sliding doors vs bifolds — which is better?
Sliding doors give you a thinner sightline (20–35mm interlock vs 90–120mm bifold meeting stiles) and bigger glass-to-frame ratio when closed. Bifolds give you near-100% wide opening when fully folded back. Choose slimline sliding for a clean look and frequent partial-opening use; choose bifold for indoor-outdoor living where you regularly fully open the entire span.
What's the difference between APX20 Plus and Cortizo Vision?
Both have 20mm interlocks and similar thermal performance. Cortizo Vision is engineered specifically for the slim aesthetic with a hidden track option (concealed in floor screed) and 320kg pane support. APX20 Plus is the value-for-money equivalent — same 20mm sightline at typically 15–20% lower fitted cost, 2700mm max pane height. For projects under 2700mm tall the systems are functionally similar; above that, Vision is the choice.
Do slimline sliding doors need a steel reinforced opening?
For 2-pane installations under 3.5m wide and 2.4m tall, no — a standard structural opening with concrete lintel is sufficient. For 3-pane and 4-pane corner configurations, or single panes above 2.7m tall carrying 300kg+ each, a structural engineer should size the lintel. Apex Glazing handles the structural calculations as part of the survey.
Are slimline sliding doors suitable for conservation areas?
Slimline aluminium sliders are usually approved at the rear of period properties in conservation areas (rear elevations are not visible from the street). Front and side elevations of listed or heritage properties typically require timber or heritage uPVC instead. Apex Glazing has installed Cortizo Vision rear extensions in Richmond, Chiswick, and Putney conservation areas.
