Bi-folding Doors
Refined aesthetics with exceptional thermal performance.
Beautiful doors from 1–7 panels wide, that flood your home with natural light.
Get a Quote
Aluminium made and finished under one UK roof
Sheerline is the aluminium window and door brand of Garnalex, founded in 2018 by Roger Hartshorn — a fenestration industry veteran who has built and sold two other major UK profile systems businesses before this one. Everything is designed and made at their own fully vertically integrated facility in Nether Heage, Derbyshire, controlling every stage from aluminium extrusion through to in-house powder coating, rather than buying in finished profile from a third party.
Five reasons homeowners choose Prestige
Scroll through to see what makes the Prestige system different — from wall-to-wall glass to the security details you won’t notice until you need them.
Bring the outside in
Bi-fold doors turn a wall into an opening the width of a room. Slim aluminium sightlines mean more glass and less frame, so light still floods the room even with the doors closed.
Featuring our unique thermal technology
A Thermlock® multi-chamber design keeps the cold out and the warmth in, giving U-values as low as 1.0 W/(m²K) triple glazed — comfortably ahead of current Building Regulations.
Balanced aesthetics
Custom single rollers do away with the need for extra mullions, keeping a consistent 138mm sightline between every sash for a clean, balanced look whichever configuration you choose.
Outstanding security built into every bi-fold
Every set comes with 5-point locking, double deadbolts and an anti-mishandling device as standard, plus full-length security interlocks on applicable styles to bind the sashes together against forced entry.
Bespoke Winkhaus ‘Thunderbolt’ locking
French pass doors use a Winkhaus “Thunderbolt” locking system with an integral finger-pull, keeping the clean look intact without a second visible handle.
The numbers that matter
Slim Sightlines
138mm
sash to sash
110mm
sash to outer frame
Max
Height
2.6m
Width
6.5m
Weight per sash
120KG
Configurations
Single
French
Folding
up to 7 pane
U-Values
1.4 U-value
W/(m²K)
Double glazed
1.0 U-value
W/(m²K)
Triple glazed*
Configurations
Available in 2 to 7 panes, opening left, right, or split both ways, plus French-door and single-door versions for narrower openings. Filter by pane count below to see each layout.
