Sheerline
Sheerline, a Garnalex brand, designs and manufactures aluminium windows, doors, and roof lanterns featuring patented Thermlock® thermal technology. It extrudes components at a vertically integrated Derbyshire facility and distributes through a nationwide UK network of approved fabricators and installers serving homeowners and trade customers.
- Company typePrivate
- Founded2020
- HeadquartersNether Heage, Belper, United Kingdom
- Headcount—
- GTM typeB2B
- OfferingHardware or Manufacturing
What Sheerline does
Sheerline, a brand of UK-based Garnalex, designs and manufactures aluminium windows, doors and roof lanterns from a vertically integrated facility in Nether Heage, Belper, Derbyshire. Its core technology stack comprises the patented Thermlock® multi-chamber thermal core, patented corner construction methods, an in-house Qualicoat 'seaside class' powder coating line, and an energy-efficient SMS HYBREX press delivering up to 55% energy savings versus traditional equipment. The product portfolio spans the Classic and Prestige window lines, multiple door categories (Heritage, Bi-fold, Lift & Slide, SheerGlide Inline Patio), and the S1 Roof Lantern and S3 Architectural Glazed Roof systems, all built on a common system architecture. The company holds independently verified U-value reports, PAS 24 security certification as standard, optional Secured by Design accreditation, and ISO 9001:2015 quality management certification.
Sheerline operates as a systems house in a B2B2C model: it extrudes aluminium and manufactures component parts in-house, then supplies those components to a nationwide UK network of approved independent fabricators and installers who produce and fit finished products for end customers. Pricing is quote-based through the fabricator channel rather than publicly listed, and the company provides training, tooling, and technical support to its trade partners. End customers are homeowners seeking thermally efficient, secure aluminium home improvements, while the primary direct customer segment is the trade fabricator/installer channel; a secondary specifier segment (architects and construction professionals) is served through the NBS Source platform.
The company was founded as a Garnalex brand in 2020 by industry veteran Roger Hartshorn, who previously founded and exited Eurocell plc and Liniar. Leadership transitioned in January 2026 with Ross Hartshorn elevated to Managing Director and Ben Hartshorn to Technical and Design Director. Sheerline is privately held under Garnalex, employs 31 people, has invested over £27M in its manufacturing base, and has been recognised with the King's Award for Innovation 2025 and a 9th-place ranking on the Oresa Growth Index.
Sheerline firmographics
Firmographics- Name
- Sheerline
- Legal name
- Sheerline
- Website
- https://sheerline.com
- Company type
- Private
- Founded year
- 2020
- Operating status
- Operating
- Short description
- Sheerline, a Garnalex brand, designs and manufactures aluminium windows, doors, and roof lanterns featuring patented Thermlock® thermal technology. It extrudes components at a vertically integrated Derbyshire facility and distributes through a nationwide UK network of approved fabricators and installers serving homeowners and trade customers.
- Ownership category
- akta.pro rank
Sheerline industry classification
Industry- Product category
- Aluminium Fenestration Systems
- NAICS
- Metal Window and Door Manufacturing (332321)
- SIC
- Metal Doors, Sash, Frames, Moldings & Trim (3442)
- akta.pro primary industry
- Metal Cladding, Soffits & Trim (Non-Panel Components) (IMADACAM)
Keywords
Where Sheerline is headquartered
LocationHeadquarters
- HQ city
- Nether Heage, Belper
- HQ country
- United Kingdom
- HQ region
- Europe
Offices1 record
Markets served
Sheerline business model
Business model- GTM type
- B2B
- Offering type
- Hardware or Manufacturing
- Cost components
- Supply Chain, Operations, Technology or R&D, Infrastructure, Personnel, Marketing or Sales
Revenue model
- Aluminium Component Systems: Sheerline extrudes aluminium and manufactures component parts that are sold to a nationwide network of trusted fabrication partners. The company is vertically integrated, manufacturing all major components at their state-of-the-art facilities in Derbyshire, UK.
Go-to-market motion1 record
Distribution channels1 record
Marketing channels7 records
Sheerline product offering
Product offeringCore offering
Sheerline operates as an aluminium systems house that extrudes aluminium and manufactures component parts for windows, doors, and roof lanterns at its vertically integrated UK facility in Derbyshire. These components are sold to a nationwide network of approved fabrication partners who manufacture finished products and install them for end customers. The product range is built on patented Thermlock® multi-chamber thermal technology and patented corner construction.
Product overview
Sheerline is a next-generation aluminium fenestration brand manufactured by Garnalex, offering a unified product range of aluminium windows, doors, and roof lanterns. The portfolio consists of two primary window lines (Classic and Prestige), three door categories (Heritage, standard Doors, and Bi-folding/Lift & Slide Patios), and two roof solutions (S1 Lantern and S3 Glazed Roof), all built on a common system architecture with patented Thermlock thermal technology. The Prestige range represents the premium tier with superior specifications, while the Classic range offers heritage-style aesthetics. Products are sold through a nationwide network of approved fabricators and installers, with the company extruding aluminium and manufacturing components in-house at their UK facility. Sheerline holds a King's Award for Innovation 2025.
Differentiator
Problem solved
Functional benefit
Brands
- Sheerline: Aluminium windows, doors and roof lantern systems featuring patented corner construction and Thermlock technology
Products and services
- Prestige Windows Premium aluminium windows with slim architectural frames, Thermlock technology for thermal performance, and common system architecture that reduces stockholding and simplifies fabrication. Built for fabricators and installers.
- Classic Windows Aluminium windows designed with aesthetics that match across the Sheerline product range, built with patented corner construction and Thermlock technology for thermal efficiency. Sold via fabricators and installers.
- Prestige Doors Premium aluminium doors offering thermal performance and security, designed to meet stringent Building Regulations requirements. Distributed through fabricator and installer network.
- Classic Heritage Door Aluminium heritage-style door with distinctive stepped feature, high-quality hardware, and steel-look aesthetics combined with modern thermal performance. Available in multiple colours including Jet Black.
- Prestige Bi-folding Doors Aluminium bi-fold doors designed for open plan living, offering light airy interiors with slim sightlines and class-leading thermal performance. Sold via approved fabricators and installers.
- Prestige Lift & Slide Patios Premium lift and slide patio doors enabling seamless connections between home and garden, featuring Sheerline's thermal lock technology and easy installation. Distributed through UK fabricator network.
- SheerGlide Inline Patio Inline patio door launched in March 2026, featuring PAS 24 approval as standard with optional Secured by Design upgrade. Part of the next-generation aluminium range. Sold via fabricators and installers.
- S1 Roof Lantern Roof lantern for bringing natural light into homes through flat roof extensions. Award-winning product (Best Technical Innovation) celebrating its 5th anniversary in 2026. Features slim aluminium profiles. Distributed via fabricator and installer network.
- S3 Glazed Roof Glazed roof system for architectural extensions, creating light-filled spaces. Features SheerVents for ventilation. Launched October 2025 as part of the next-generation aluminium range. Sold via fabricators and installers.
Quantifiable outcome
- Energy savings of up to 55% compared to traditional presses through SMS HYBREX technology
- +2 more outcomes
Companies that use Sheerline
Customer profileNamed customers3 records
Segments3 records
Ideal customer profiles3 records
Sheerline technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature6 records
Sheerline partnerships and signals
Strategic signalPartnerships
Three partnerships are on record, tiered core and minor.
- Select WindowscoreSelect Windows diversified their product offering by adding Sheerline aluminium products to their showroom. The company installed a Classic Heritage Door at their showroom entrance, providing access for customers to view Sheerline products.
- Marlin WindowscoreMarlin Windows became a new fabricator for Sheerline products. Chris Cooke (Sheerline Bespoke's Commercial Director) and Adrian Martin (Marlin Windows Managing Director) announced the partnership.
- WindowiseminorWindowise switched to Sheerline, with the company stating 'It's one of the best decisions I've ever made' regarding the partnership.
Scale indicators4 records
Recent moves6 records
Expansion highlights6 records
Sheerline competitors and assessment
Company assessmentDirect peers
- Smart Systems (Smart Architectural Aluminium): One of the UK's largest aluminium systems houses offering windows, doors, and curtain walling through a fabricator network. Directly competes with Sheerline across the same B2B2C systems-house model and product categories (windows, bi-folds, patios).
- Senior Architectural Systems: UK-based aluminium and PVC-u systems house providing windows, doors, and curtain wall systems through fabricators. Competes directly with Sheerline in aluminium fenestration and has overlapping fabrication partner channels across the UK.
- AluK (UK): UK subsidiary of the AluK Group, one of Europe's leading aluminium systems brands offering window, door, and façade systems. Directly comparable systems-house business model with a UK-wide fabricator network targeting the same trade and homeowner segments as Sheerline.
- Reynaers Aluminium (UK): UK arm of Belgian-headquartered Reynaers, a premium aluminium window, door, and façade systems provider. Competes directly with Sheerline in the premium and architectural aluminium segment via a fabricator network, including bi-fold and patio doors.
- Schüco UK: UK operations of German aluminium systems giant Schüco, offering high-end windows, doors, and façades with strong emphasis on thermal performance and security. Direct peer for Sheerline's premium aluminium systems, especially in the architect/specifier channel.
- Technal (UK / Hydro): UK operations of the Hydro-owned Technal brand, supplying architectural aluminium window, door, and façade systems through fabricators. Competes directly with Sheerline in premium and commercial/specifier-driven aluminium fenestration.
- Origin (Origin Frames): UK manufacturer of premium aluminium bi-fold, sliding, and front doors, plus windows, sold through a network of approved installers. Highly comparable direct peer to Sheerline on product mix (bi-folds, patios) and on the premium thermally-efficient positioning in the UK market.
Broad incumbents
- Eurocell plc: UK-listed PVC-u and aluminium systems house and recycling business, previously founded by Sheerline Chairman Roger Hartshorn. Comparable as an incumbent UK systems house that has scaled, with broader product and recycling verticals than Sheerline's focused aluminium range.
- Liniar (Quanex Building Products): UK PVC-u and aluminium systems brand, also previously founded by Roger Hartshorn and now owned by US-based Quanex. Comparable as a UK systems house that scaled to exit; relevant precedent for Sheerline's founder and operating model, though Liniar's core is PVC-u rather than aluminium.
Emerging players
- Aluprof UK: European aluminium systems house (part of Grupa Kęty) expanding in the UK with windows, doors, and façade systems. Emerging direct competitor to Sheerline in the UK premium aluminium market via a fabricator network.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat6 records
Key risks6 records
Key highlights7 records
Customer concentration
Sheerline social profiles
Digital presenceSheerline compliance and trust
Trust signalCompliance6 records
Sheerline financial estimates
Financial estimateRevenue estimate
Valuation estimate
Sheerline leadership team
Management profileNumber of profiles
Profiles11 records
Sheerline funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
Sheerline M&A and investment
M&A and investmentM&A
Investments
M&A and investment is available on the Subscription and Enterprise plan.Contact sales →
Frequently asked questions about Sheerline
What does Sheerline do?
Sheerline operates as an aluminium systems house that extrudes aluminium and manufactures component parts for windows, doors, and roof lanterns at its vertically integrated UK facility in Derbyshire. These components are sold to a nationwide network of approved fabrication partners who manufacture finished products and install them for end customers. The product range is built on patented Thermlock® multi-chamber thermal technology and patented corner construction.
Is Sheerline a public or private company?
Sheerline is a private company. It is classified as family owned and is currently operating.
When was Sheerline founded?
Sheerline was founded in 2020.
Where is Sheerline based?
Sheerline is headquartered in Nether Heage, Belper, United Kingdom, in the Europe region.
How does Sheerline make money?
One revenue line is on record: aluminium Component Systems.
Who are Sheerline's main competitors?
Direct peers on record are Smart Systems (Smart Architectural Aluminium), Senior Architectural Systems, AluK (UK), Reynaers Aluminium (UK), Schüco UK, Technal (UK / Hydro) and Origin (Origin Frames). Broad incumbents are Eurocell plc and Liniar (Quanex Building Products). Aluprof UK is listed as an emerging player.
Does Sheerline have an API?
No public API is recorded for Sheerline.
What industry is Sheerline in?
Sheerline's product category is Aluminium Fenestration Systems. Its primary akta.pro industry code is IMADACAM, Metal Cladding, Soffits & Trim (Non-Panel Components). Its NAICS code is 332321 and its SIC code is 3442.