The Sash Window Workshop
The Sash Window Workshop is a UK-based, founder-led bespoke manufacturer and installer of Accoya timber windows and doors, serving owners of period and listed properties across London and Southern England with installation, and nationwide via supply-only.
- Company typePrivate
- Founded1994
- HeadquartersBracknell, United Kingdom
- Headcount51–100
- GTM typeB2C
- OfferingHardware or Manufacturing
What The Sash Window Workshop does
The Sash Window Workshop Trading Limited is a privately held, UK-based bespoke manufacturer and installer of timber windows and doors, founded in 1994 and headquartered at 4 Kiln Lane, Bracknell, Berkshire. The company manufactures exclusively from Accoya modified timber (acetylated, FSC-certified, class-1 durability) in its Berkshire workshop, producing sash windows, casement windows, front doors, French doors, bi-fold and sliding doors, and secondary glazing units, backed by a 50-year anti-rot guarantee and 20-year joinery warranty. Its heritage double-glazing system (narrow 8mm spacer with Argon fill) and factory-finished three-coat painting process are designed to meet conservation-area planning requirements while delivering modern thermal and acoustic performance.
The business operates a hybrid go-to-market model: an in-house field-sales and installation service covering London and Southern England using expert surveyors and employed fitters (charged at £600 per day per fitter), combined with a nationwide supply-only channel for customers arranging their own installation. Revenue is generated from one-off project sales on quote-based pricing (25% deposit, interim payment before works commence, final payment on completion), plus ancillary draught-proofing and timber-repair services. Customers span residential homeowners of period properties (primary segment), listed-building and conservation-area owners, and commercial/institutional clients including Buckingham Palace, St James's Palace, the Royal Military Academy Sandhurst, the Royal Academy of Music, and The Grove Hotel.
The company carries an unusually deep stack of UK trade credentials for its size: FENSA registration, 11 consecutive years as a Which? Trusted Trader (with two Trusted Trader of the Month awards), Guild of Master Craftsmen and BWF membership, SafeContractor certification, FSC Chain-of-Custody, Carbon Neutral Plus re-certification (December 2025), and PAS 24:2022 certification for a new box sash window system (February 2026). Leadership is founder-led, with Managing Director Richard Dollar, Operations Manager Helen Barnes, and Finance Director Andrew Hemingway, and the workforce (51–100 employees) shows strong tenure — 35 staff were recognised in 2025 for 495 combined years of service. The company is bootstrapped with no disclosed funding rounds, acquisitions, or external ownership.
The Sash Window Workshop firmographics
Firmographics- Name
- The Sash Window Workshop
- Legal name
- The Sash Window Workshop Trading Limited
- Website
- https://sashwindow.com
- Company type
- Private
- Founded year
- 1994
- Operating status
- Operating
- Headcount range
- 51–100 employees
- Short description
- The Sash Window Workshop is a UK-based, founder-led bespoke manufacturer and installer of Accoya timber windows and doors, serving owners of period and listed properties across London and Southern England with installation, and nationwide via supply-only.
- Ownership category
- akta.pro rank
The Sash Window Workshop industry classification
Industry- Product category
- Timber Windows and Doors
- NAICS
- Wood Window and Door Manufacturing (321911)
- SIC
- Millwood, Veneer, Plywood, & Structural Wood Members (2430)
- akta.pro primary industry
- Interior Doors (IMADAIAB)
- akta.pro secondary industries
- Window & Door Frame/Sash Replacement (HSAPAJAF), Window Sash, Frame & Wood Rot Repair (HSAGABAD), Stair Parts, Railings & Architectural Woodwork (HSAPAIAJ)
Keywords
Where The Sash Window Workshop is headquartered
LocationHeadquarters
- HQ city
- Bracknell
- HQ country
- United Kingdom
- HQ region
- Europe
Offices1 record
Markets served
The Sash Window Workshop business model
Business model- GTM type
- B2C
- Offering type
- Hardware or Manufacturing
- Cost components
- Personnel, Supply Chain, Operations, Marketing or Sales, Infrastructure
Revenue model
- Timber Windows and Doors - Supply and Install: Bespoke timber windows and doors manufactured and installed by in-house teams. Services include sash windows, casement windows, front doors, French doors, bi-fold/sliding doors, and secondary glazing. Revenue generated from manufacturing and installation labor.
- Supply Only: Nationwide supply of bespoke timber windows and doors without installation. Customers arrange their own installation or use local contractors.
- Draught Proofing and Repairs: Specialist draught-proofing services and timber repairs for existing windows, extending the life of existing joinery.
Pricing tiers
| Model | Billing | Price |
|---|---|---|
| Unit Pricing | Pay-as-you-go | Survey and Consultation |
| Unit Pricing | Pay-as-you-go | Installation Service |
| Other | Multi-year contract | Bespoke Timber Windows and Doors |
Go-to-market motion1 record
Distribution channels2 records
Marketing channels7 records
The Sash Window Workshop product offering
Product offeringCore offering
The Sash Window Workshop manufactures and installs bespoke timber windows and doors, specialising in sash windows, casement windows, front doors, French doors, bi-fold/sliding doors, and secondary glazing for period, listed, and contemporary properties. All products are crafted from Accoya timber in the company's Berkshire workshop, with a 50-year anti-rot guarantee. The company offers both supply-and-install services across London and Southern England, and supply-only nationwide, alongside specialist draught-proofing and timber repair services.
Product overview
The Sash Window Workshop is a specialist manufacturer and installer of bespoke timber windows and doors, serving owners of period and contemporary properties since 1994. The product portfolio centres on sash windows and casement windows (the core products), complemented by a full range of external timber doors including front doors, French doors, and bi-fold/sliding doors. Supporting services include secondary glazing for listed buildings and draught-proofing for existing joinery. Both supply-only (nationwide) and supply-and-install (London and Southern England) service models are offered. All products are manufactured in the company's Berkshire workshop, with Accoya timber as the primary material backed by a 50-year anti-rot guarantee.
Differentiator
Problem solved
Functional benefit
Products and services
- Sash Windows Bespoke timber box sash windows and bay sash windows, typically double-glazed, manufactured in the Berkshire workshop from Accoya timber with a 50-year anti-rot guarantee. Designed for period properties and modern homes seeking high-performance timber windows.
- Casement Windows Traditionally styled timber casement windows delivering outstanding energy efficiency, crafted from Accoya for exceptional durability. Suitable for period and contemporary properties.
- Front Doors Bespoke timber entrance doors designed to complement period property character, made from Accoya with 50-year anti-rot guarantee. Combines refined design with robust security.
- French Doors Bespoke timber French doors combining refined design with robust security, crafted from Accoya for durability and long-term performance.
- Bi-Fold/Sliding Doors Timber bi-fold and sliding doors made to measure, designed to complement property character using Accoya timber for durability and modern performance.
- Secondary Glazing Bespoke timber secondary glazing units that discreetly boost thermal and acoustic insulation without altering property character, suitable for listed buildings and conservation areas.
- Draught Proofing and Timber Repairs Specialist draught-proofing and timber repair service extending the life of existing joinery with precision craftsmanship. Targets owners of period properties seeking to improve performance without full replacement.
- New Sashes into Existing Window Frames New sash windows installed into existing window frames, typically used for listed buildings where full frame replacement requires planning consent. Retains original frame while upgrading the moving parts.
- Supply Only Service Supply-only option for bespoke timber windows and doors delivered nationwide, for customers arranging their own installation or using local contractors.
- Installation Service Expert in-house installation service across London and Southern England by experienced craftspeople, covering sash windows, casement windows, doors, secondary glazing, and draught-proofing installations.
- PAS 24 Certified Box Sash Window System A box sash window system that has passed independent PAS 24:2022 testing, the UK benchmark for enhanced security performance in windows and doors.
Quantifiable outcome
- BFRC Energy Ratings up to A-rated for Accoya sash windows and casement windows
- +3 more outcomes
Companies that use The Sash Window Workshop
Customer profileNamed customers16 records
Segments3 records
Ideal customer profiles3 records
The Sash Window Workshop technology and API
TechnologyTechnology focussed No
API detail
- Has API
- No
- API docs
- API detail
Core technology
AI maturity
App detail
Feature3 records
The Sash Window Workshop partnerships and signals
Strategic signalPartnerships
One partnership is on record.
- Accsys Technologies (Accoya)coreThe Sash Window Workshop is an Accoya Approved Manufacturer, using Accoya modified timber as standard for all windows and doors. Accoya is engineered timber treated with acetic acid under high pressure, providing class 1 durability and 50-year anti-rot guarantee. This is a core partnership as Accoya is the primary material used in all products.
Scale indicators6 records
Recent moves5 records
Expansion highlights5 records
The Sash Window Workshop competitors and assessment
Company assessmentDirect peers
- Bereco: UK timber window and door specialist using Accoya-engineered timber; targets period property owners and conservation projects with comparable bespoke manufacturing and heritage-compliant glazing offerings.
- Evolution Windows: UK manufacturer of timber-alternative and traditional timber windows targeting period and conservation properties; offers a supply-only and supply-and-install model comparable to The Sash Window Workshop's hybrid distribution.
- Westbury Windows & Joinery: Bespoke UK joinery producing timber windows, doors, and screens for high-end residential and heritage projects; comparable in craftsmanship-led positioning and conservation-area expertise.
- Mumford & Wood: UK manufacturer of bespoke timber windows and doors, including flush casements and heritage sliding sashes; serves a similar period-property and conservation-area customer base with comparable Accoya/engineered timber specifications.
- Dale Joinery: UK designer and manufacturer of timber windows, doors, and screens for period, heritage, and contemporary properties; competes directly on bespoke joinery, conservation compliance, and supply-only/specifier channels.
- The Rose Collection: Heritage-focused UK timber window maker specialising in sliding sash, casement, and shaped units for listed and period properties; competes on craftsmanship, conservation compliance, and Accoya-based products.
Others
- Accsys Technologies (Accoya): Manufacturer of Accoya modified timber — the core raw material used in The Sash Window Workshop's products; a critical upstream supplier and ecosystem partner rather than a downstream competitor.
Broad incumbents
- Everest: Major UK home improvements incumbent selling windows, doors, and conservatories nationwide; competes on convenience and scale rather than bespoke timber craftsmanship for period properties.
- Anglian Home Improvements: Large UK home improvement incumbent covering windows (uPVC, timber, aluminium), doors, and conservatories — overlaps with The Sash Window Workshop on window/door replacement but competes from a low-cost, mass-market position rather than a heritage/craftsmanship niche.
Regional players
- Chelsea Sash Windows: London-focused sash window specialist offering manufacture, install, and repair; an area competitor to The Sash Window Workshop in its core London install market with overlapping period-property customer base.
Market position
Strengths5 records
Weaknesses5 records
Competitive moat5 records
Key risks6 records
Key highlights7 records
Customer concentration
The Sash Window Workshop social profiles
Digital presenceThe Sash Window Workshop compliance and trust
Trust signalCompliance11 records
The Sash Window Workshop financial estimates
Financial estimateRevenue estimate
Valuation estimate
The Sash Window Workshop leadership team
Management profileNumber of profiles
Profiles3 records
The Sash Window Workshop funding detail
Funding detailFunding overview
Funding rounds
Investors
Funding detail is available on the Subscription and Enterprise plan.Contact sales →
The Sash Window Workshop 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 The Sash Window Workshop
What does The Sash Window Workshop do?
The Sash Window Workshop manufactures and installs bespoke timber windows and doors, specialising in sash windows, casement windows, front doors, French doors, bi-fold/sliding doors, and secondary glazing for period, listed, and contemporary properties. All products are crafted from Accoya timber in the company's Berkshire workshop, with a 50-year anti-rot guarantee. The company offers both supply-and-install services across London and Southern England, and supply-only nationwide, alongside specialist draught-proofing and timber repair services.
Is The Sash Window Workshop a public or private company?
The Sash Window Workshop is a private company. It is classified as founder individual operated bootstrapped and is currently operating.
When was The Sash Window Workshop founded?
The Sash Window Workshop was founded in 1994. It employs 51 to 100 people.
Where is The Sash Window Workshop based?
The Sash Window Workshop is headquartered in Bracknell, United Kingdom, in the Europe region.
How does The Sash Window Workshop make money?
Three revenue lines are on record. Timber Windows and Doors - Supply and Install is the primary driver. The others are supply Only and draught Proofing and Repairs.
Who are The Sash Window Workshop's main competitors?
Direct peers on record are Bereco, Evolution Windows, Westbury Windows & Joinery, Mumford & Wood, Dale Joinery and The Rose Collection. Accsys Technologies (Accoya) is listed as an others. Broad incumbents are Everest and Anglian Home Improvements. Chelsea Sash Windows is listed as a regional player.
Does The Sash Window Workshop have an API?
No public API is recorded for The Sash Window Workshop.
What industry is The Sash Window Workshop in?
The Sash Window Workshop's product category is Timber Windows and Doors. Its primary akta.pro industry code is IMADAIAB, Interior Doors, with a secondary code of HSAPAJAF, Window & Door Frame/Sash Replacement. Its NAICS code is 321911 and its SIC code is 2430.