Liniar

Liniar Windows & Doors

UK-designed, lead-free uPVC profile systems. Patented bubble gasket. The mainstream specification of choice for residential trade. The Plastic Centre stocks Liniar’s full range across our 21 UK branches — casement and tilt-and-turn windows, vertical sliding sash, bi-fold doors and windows, and the EnergyPlus high-thermal range.

Who Are Liniar?

Liniar is a UK-headquartered uPVC profile manufacturer based in Denby, Derbyshire, owned by the Quanex Building Products group. Founded in 2007, Liniar designed its window, door and decking systems from a clean sheet of paper — making it one of the few profile systems on the market designed in the 21st century specifically for modern Building Regulations and trade fabrication. The Denby manufacturing site is one of the largest single-site PVC extrusion plants in Europe.

Why Liniar?

Lead-free uPVC	The Liniar profile system is fully lead-free, using calcium-zinc stabilisers in place of the lead-based stabilisers still common in many older profile designs. Better long-term environmental credentials and improved colour stability.
Patented bubble gasket	Liniar’s double-action bubble gasket is fitted at the corners as a single continuous loop — eliminating the corner mitre leaks that plague conventional profiles and dramatically improving weather seal performance.
Reduced steel reinforcement	Designed with reduced steel content — lowering thermal bridging through the frame, reducing weight, and improving recyclability at end-of-life.
UK-designed for UK regs	Designed for current UK Building Regulations rather than retrofitted European designs. Standard A+ Window Energy Rating across the casement range; A++ achievable on full EnergyPlus specifications.
Bi-fold range — uPVC and aluminium	Liniar offer both uPVC bi-fold doors and bi-fold windows in the same profile family — the only major UK uPVC manufacturer with a complete bi-fold residential offering across both door and window applications.
Mock Sash Horn variant	A clever cost-effective variant of the casement profile with sash-horn detailing — gives a period-property look at a casement price, ideal for budget-conscious heritage-style refurbishments.
Single-source colour palette	Liniar’s full colour palette — including foiled finishes — works consistently across windows, doors, bi-folds and even composite decking, allowing for whole-elevation colour coordination.

Liniar Systems We Stock

System	Material / Profile	Best U-value	Best for
70mm EnergyPlus Casement	uPVC, 70mm, 6 symmetrical chambers	0.8 W/m²K (full EnergyPlus spec)	Mainstream casement windows — A+ as standard, A++ achievable
70mm Flush Sash	uPVC flush-finish casement variant	As 70mm EnergyPlus	Conservation-area replacements, contemporary new-build, timber-look exterior
70mm Tilt & Turn	uPVC, dual-action tilt-and-turn	0.93 W/m²K (triple-glazed)	Mainstream tilt-and-turn windows
Zero|90 Tilt & Turn	uPVC, 90mm Passivhaus platform	0.71 W/m²K (triple-glazed argon)	Passivhaus + Approved Document Q new-build, at lower price than REHAU GENEO
Vertical Sliding Sash	uPVC sliding sash with spring-balance mechanism	WER A+ rated	Sash windows for period properties — with authentic sash horns and astragal bars
Mock Sash Horn Window	uPVC casement with sash-horn detailing	WER A+ rated	Period-look exterior at a casement budget — popular on terraces and rental refurbishments
uPVC Bi-Fold Window	uPVC, 2–7 panel concertina	1.2 W/m²K (thermal lock)	Kitchen servery bi-fold windows
uPVC Bi-Fold Door	uPVC, multi-panel concertina with patented low threshold	C to A+ rated	Bi-fold doors for residential garden access
French Door	uPVC, 4-chamber or EnergyPlus 6-chamber	C to A+ rated	French doors with Part M ramp threshold options
Patio Door	uPVC, ModLok™ frame-integrated locking	C to A+ rated	Patio doors — the most secure uPVC sliding patio in the residential market

Distinctive Technology

Patented Double-Action Bubble Gasket

Conventional profile systems use mitred gaskets at the corners — a known weak point where weather seals fail. Liniar’s gasket is a single continuous bubble seal that wraps the corners as one piece, delivering 30% better compression than standard gasket systems and eliminating the corner-leak failure mode.

Lead-Free Profile

Liniar uses calcium-zinc stabilisers in place of lead-based stabilisers. Lead is still permitted in uPVC under current REACH regulations but is increasingly being phased out across the European market. Liniar were one of the first major UK manufacturers to commit to fully lead-free production.

ModLok™ Patio Door Locking

The Liniar patio door uses a patented modular locking mechanism built directly into the frame structure rather than surface-mounted. Combined with anti-snap cylinders covered by the handle and high-security hook locks with shootbolts, ModLok™ makes the Liniar patio one of the most secure uPVC sliding doors available.

Air Glide Wheels

The Liniar patio door uses air-glide wheels that deliver effortless smooth sliding from first use to last — with built-in self-cleaning brushes that sweep debris from the track on every closing cycle. No more sticking, rocking or grinding patio doors.

Sustainability & Compliance

• Lead-free uPVC — calcium-zinc stabilisers throughout the profile range
• BS EN 12608-1 certified profile system
• PAS 24 enhanced security across the range
• Secured by Design accredited — standard on most casements and tilt-turns
• Approved Document Q compliant (Zero|90 platform meets Part Q out of the box)
• Approved Document L energy performance comfortably exceeded
• Passivhaus Institute certified — Zero|90 tilt-and-turn at U-values down to 0.71 W/m²K
• 10-year guarantee on Liniar profile as standard
• BS6375 air, water and wind tested across the range

Where Liniar Sits in Our Range

We stock Liniar alongside REHAU and Smart Systems profile systems. Quick choosing guide:

If you want…	Liniar spec
Best price/performance for mainstream uPVC casement	70mm EnergyPlus Casement (A+ as standard)
Passivhaus-certified at lower price than REHAU	Zero|90 tilt-and-turn (Uw 0.71 W/m²K)
Period-look exterior on a casement budget	Mock Sash Horn Window
Genuine traditional uPVC sash	Vertical Sliding Sash — or specify REHAU Heritage for stricter conservation areas
Most secure uPVC patio door	Liniar patio with ModLok™
Kitchen-to-garden bi-fold window	Liniar uPVC bi-fold window (2–7 panels)
Aluminium contemporary look	Specify Smart Systems instead
uPVC panel door (front / back entrance)	Specify Hurst instead (Liniar don’t make panel doors)

How to Order

Liniar windows and doors are made-to-measure products, fabricated by approved Liniar partners and supplied through our 21 UK branches. Lead times typically 2–4 weeks from final specification (faster than REHAU on most products). For a quote, use the enquiry form on the relevant casement, tilt-and-turn, sash, bi-fold window, bi-fold door, French door, patio door page, or contact your nearest branch.

Frequently Asked Questions

Where are Liniar windows manufactured?

The Liniar profile is extruded at the company’s Denby, Derbyshire site — one of the largest single-site PVC extrusion plants in Europe. Fabrication into finished window and door units happens at approved UK fabricator partners.

What does “lead-free” mean for Liniar?

Many older uPVC profiles use lead-based stabilisers to extend the polymer’s working life. Liniar uses calcium-zinc stabilisers throughout the range — better long-term environmental credentials, improved colour stability and a profile that’s easier to recycle at end-of-life.

What’s the difference between EnergyPlus and Zero|90?

EnergyPlus is the headline thermal specification for the standard 70mm Liniar profile — a combination of glazing, gasket, profile chamber configuration and reinforcement choices that together deliver Uw values as low as 0.8 W/m²K. Zero|90 is a separate 90mm-deep platform purpose-designed for Passivhaus — available as tilt-and-turn, with U-values down to 0.71 W/m²K and Approved Document Q compliance.

Is Liniar cheaper than REHAU?

Generally, yes — particularly on mainstream casement and tilt-turn specifications. Liniar wins on price-performance for typical residential builds. REHAU pulls ahead when Passivhaus certification (GENEO), heritage detailing (Heritage VS) or fibre-composite security is the priority.

Are Liniar bi-fold windows the same as bi-fold doors?

They share the same profile family but are sized differently. Bi-fold windows sit at sill / worktop height (typical for kitchen serveries) and use 2–7 smaller panels. Bi-fold doors extend to floor level and use full-height panels. Both are made from the same Liniar uPVC and can be specified in matching colours for a coherent elevation.

What warranty applies to Liniar?

10-year guarantee on the Liniar profile as standard. Hardware (locks, hinges, gaskets) carries separate component warranties — speak to our team at point of quotation for the full schedule.

Can I match Liniar windows and doors across the same elevation?

Yes — this is one of Liniar’s strongest selling points. The full Liniar colour palette works consistently across casement, tilt-turn, sash, bi-fold windows, bi-fold doors, French doors, patio doors and even Liniar composite decking. Whole-elevation colour matching out of one supplier.

Ready to specify?

For a Liniar window or door quote, use the enquiry form on the relevant windows or doors page, or contact your nearest branch.