Keystone Supplies, Unit 17 Storforth Lane Trading Estate,
Hasland, Chesterfield, Derbyshire, United Kingdom S41 0QQ
01246 201523

All Our Timber Windows

Sash Windows
Casement Windows
Bespoke timber windows bring unmatched natural warmth, architectural distinction, and enduring character to any property. Handcrafted directly within our specialist joinery workshop, our sliding sash and casement collections combine traditional British timber proportions with modern thermal insulation, multi point security, and breathable weather resistant finishes. Whether you are sensitively restoring a listed period home or designing an ambitious new architectural residence, explore timber glazing built without compromise.
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Traditional British Craftsmanship & Sliding Sash Elegance

Timber Sash Windows

Built to preserve the architectural character of Georgian, Victorian, and Edwardian properties, our timber sliding sashes pair historical joinery details with modern, draught free comfort. Individually made to measure, they feature slender meeting rails, sculptured sash horns, and your choice of traditional cords and weights or modern concealed spiral balances. Engineered timber frames and perimeter brush sealing eliminate rattles and heat loss, ensuring effortless vertical sliding and dependable security year after year.
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Layers of pure and laminated timber counteract natural wood grain movement. By distributing structural tension across engineered layers, our timber frames resist twisting, warping, and seasonal sticking to guarantee smooth year round operation in homes across the UK.
Engineered for sensitive heritage restorations and modern projects alike, our timber sashes can be specified with traditional cords and counterweight chains or concealed pre tensioned spiral balances for effortless vertical operation.
Individually handcrafted to your exact structural aperture dimensions, available in authentic flush sash or rebated stormproof casements. Tailored to satisfy strict local authority planning and conservation area requirements for heritage renovations and bespoke new builds.
Advanced double and triple glazed sealed units featuring low emissivity coatings and warm edge spacer technology deliver thermal values twice as efficient as standard glazing, easily surpassing UK Part L Building Regulations. Fitted with internal security beading from the room side to eliminate external pane removal.
Precision engineered joinery tolerances and high performance perimeter weather seals deliver whisper quiet, beautifully smooth vertical sliding that makes everyday operation an effortless pleasure.
Extensive collections of luxury architectural hardware, including precision British brassware by Samuel Heath alongside hand forged monkey tail handles, pear drop fasteners, and working peg stays to suit both period and modern interiors.
Bespoke Joinery & Authentic Character

Timber Casement Windows

Handcrafted directly in our workshop, Keystone timber casements pair authentic British joinery aesthetics with modern thermal efficiency. Available in classic flush profiles or weather rebated stormproof designs, each window is built using multi layer engineered timber sections to stop warping, twisting, and sticking through changing seasons. Finished with breathable factory applied microporous coatings, dual perimeter draught seals, and concealed multi point locking, our casements deliver smooth everyday operation and enduring kerb appeal.
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Layers of pure and laminated timber counteract natural wood grain movement. By distributing structural tension across engineered layers, our timber frames resist twisting, warping, and seasonal sticking to guarantee smooth year round operation in homes across the UK.
Integrated multi point shootbolts, heavy duty espagnolette systems, and key locking fasteners engineered to meet rigorous PAS 24 and Secured by Design standards. Delivering robust physical defence against forced entry without compromising traditional timber aesthetics.
Individually handcrafted to your exact structural aperture dimensions, available in authentic flush sash or rebated stormproof casements. Tailored to satisfy strict local authority planning and conservation area requirements for heritage renovations and bespoke new builds.
Advanced double and triple glazed sealed units featuring low emissivity coatings and warm edge spacer technology deliver thermal values twice as efficient as standard glazing, easily surpassing UK Part L Building Regulations. Fitted with internal security beading from the room side to eliminate external pane removal.
Designed for historic character cottages and sharp contemporary residences alike. Fully customisable with authentic Georgian astragal glazing bars, leaded layouts, acoustic laminates, and decorative etched or stained glass patterns crafted to your exact design scheme.
Extensive collections of luxury architectural hardware, including precision British brassware by Samuel Heath alongside hand forged monkey tail handles, pear drop fasteners, and working peg stays to suit both period and modern interiors.
Full Flexibility To Perfect Your windows

Double & Triple Glazing For All Timber Windows

Achieve exceptional thermal performance without compromising traditional timber proportions. Our bespoke wooden windows accommodate high performance double and triple glazed units featuring low emissivity coatings, warm edge spacer bars, and argon cavity fills to comfortably exceed UK Part L Building Regulations. From ultra slim heritage glazing designed for sensitive period restorations to acoustic laminated glass that shuts out road traffic, every glass unit is fitted with room side internal beading for maximum weather deflection and security.
Handcrafted Joinery & Tailored Detailing

Endlessly customisable Timber Windows

From traditional sliding sash windows to authentic casements, every timber frame we build is tailored to your exact specifications. Explore limitless design freedom with sustainably sourced engineered hardwoods and pure timber, bespoke heritage colour palettes, custom glazing bar arrangements, and quality forged ironmongery. Experience the tactile quality, smooth operation, and exceptional joinery standards first hand by exploring the collection in our dedicated showroom.
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Architectural Ironmongery

Tactile Precision & Authentic Detailing

Historically accurate ironmongery paired with concealed multi-point PAS 24 security mechanisms.

Traditional monkey-tail fasteners and peg stays

Heritage & Period Ironmongery

Classic forged hardware tailored for sash and casement period restorations.

  • Authentic Monkey-Tail & Pear-Drop Fasteners
  • Working Locking Peg Stays & Dummy Stays
  • Sash Fitch Fasteners, Pulleys & Acorn Lifts
Modern flush architectural levers

Contemporary & Minimalist Suite

Sleek, low-profile architectural levers designed for flush casement apertures.

  • Precision-Engineered Inline Lever Handles
  • Concealed Sash Fasteners & Espagnolettes
  • Minimalist Low-Profile Flush Escutcheons
Architectural Finishes:
Aged Brass Antique Bronze Polished Chrome Satin Nickel Matt Black
Light Diffusion & Privacy

Architectural Privacy Glass

Diffuse daylight without compromising privacy using contemporary textures and authentic heritage finishes.

Reeded fluted glass texture
Level 2 Privacy Max Light

Reeded / Fluted

Linear parallel texture that refracts harsh glare and silhouettes while maximizing natural light diffusion.

Acid etched satin obscure glass
Level 4 Privacy Ultra Smooth

Acid-Etched Satin

Silky, non-porous frosted finish that resists finger marks and cleans effortlessly unlike sandblasted glass.

Victorian heritage starburst etched glass
Level 4 Privacy Period Detail

Heritage Etched

Traditional margin-line starburst patterns and etched corner accents designed for period Victorian sashes.

Contemporary opaque frosted glass
Level 5 Privacy Full Obscure

Contemporary Opaque

Uniform, dense privacy field suited for bathroom apertures, cloakrooms, and entrance sidelights.

Factory-Applied Protection

Architectural Palettes & Translucent Stains

Advanced 3-stage microporous spray finishes engineered to breathe with natural timber, extending maintenance cycles up to 8–10 years.

Chalk White RAL 9010
Agate Grey RAL 7038
Keystone Olive Heritage Muted
Slate Moss RAL 7009
Anthracite RAL 7016
Cotswold Cream RAL 1013

Dual-Colour Specification

Specify contrasting exterior and interior colours. Harmonise exterior brickwork with Anthracite while maintaining a soft, neutral palette indoors.

Available across all Sash & Casement profiles →

Translucent Wood Stains

UV-resistant, breathable oils and translucent stains allow the prominent grain of European Oak and Meranti to show through with complete protection.

Available on Oak & Hardwood options →
High-Performance Sealed Units

Specialist Glazing Configurations

Thermally broken insulated glass units tailored to acoustic conditions, solar loads, and conservation standards.

Acoustic Laminate

Up to 42dB Cut

Asymmetric glass thicknesses with a PVB interlayer that disrupts noise resonance and traffic roar.

Road & Rail Corridors

Solar Control

g-Value: 0.38

Microscopic coating reflects unwanted solar heat gain while preserving crystal-clear natural illumination.

South Elevations

Slimline Heritage

12mm–14mm Profile

Narrow gas-filled units engineered to fit traditional glazing bars for Conservation and Listed homes.

Conservation Areas

Triple Passivhaus

0.8 W/m²K U-Value

Dual warm-edge cavity units delivering maximum thermal insulation for near-zero heat loss builds.

Passivhaus Builds
Standard on all units: Warm-Edge Spacers • 90% Argon Cavity • Low-E Shield • Internal Room-Side Beading
Conscious Craftsmanship & Material Selection

Sustainably Sourced, Engineered for Longevity

Every timber window we craft begins with responsibly harvested, certified wood. Engineered in opposing laminated layers, each profile cancels out natural movement and warping to eliminate seasonal sticking.

Accoya Wood

Acetylated Softwood
50 Yr Anti-Rot
FSC Certified
Treated via non-toxic acetylation to alter wood at the molecular level. Virtually immune to moisture, rot, and insects, ensuring factory paint coatings last up to twice as long without cracking.
Sutiable for: South facing exposures, harsh weather, and flawless painted sashes.

European Oak

Native Hardwood
~720 kg/m3
100% FCS Sourced
The definitive architectural choice for British period properties. Heavy, dense, and naturally tannin-rich with pronounced medullary ray figures that bring timeless character to bespoke joinery.
Sutiable for: Period restorations, translucent stains, and exposed grain finishes.

Red Grandis

Plantation Hardwood
Pure Plantation
Engineered 3-ply
A sustainable, fast growing hardwood cultivated on FSC-certified single source plantations. Delivers remarkable dimensional consistency, dense cell structure, and an ultra fine machined surface.
Sutiable for: Contemporary flush casements and high end smooth paint finishes.

Meranti

Selected Hardwood
High Density
PEFC Verified
A traditional benchmark in British window joinery. Kiln dried and laminated into opposing plies, Meranti provides natural fungal resistance, strong acoustic dampening, and reliable impact strength.
Sutiable for: Deep rich wood stains, heritage rennovations, and stormproof casements.
The Keystone Guarantee: All timber is 100% FSC / PEFC certified and factory-sealed with breathable, microporus coatings.
Architectural Ironmongery

Tactile Precision & Authentic Detailing

Historically accurate ironmongery paired with concealed multi-point PAS 24 security mechanisms.

Heritage & Period Ironmongery

Classic forged hardware tailored for sash and casement period restorations.
  • Authentic Monkey tail & Pear drop Fasteners
  • Working Locking Peg Stays & Dummy Stays
  • Sash Fitch Fasteners, Pulleys & Acorn Lifts

Contemporary & Minimalist Suite

Sleek, low-profile architectural levers designed for flush casement apertures.
  • Precision Engineered Inline Lever Handles
  • Concealed Sash Fasteners & Espagnolettes
  • Minimalist Low Profile Flush Excutcheons
Architectural Finishes:
Aged Brass
Antique Brone
Polished Chrome
Satin Nickel
Matte Black
Light Diffusion & Privacy

Architectural Privacy Glass

Diffuse daylight without compromising privacy using contemporary textures and authentic heritage finishes.
Level 3 Privacy
Period Detail

Cotswold, Waterfall

Traditional margin-line starburst patterns and etched corner accents designed for period Victorian sashes.
Level 4 Privacy

Crepi clear

Traditional margin-line starburst patterns and etched corner accents designed for period Victorian sashes.
Level 3 Privacy

Atlantic clear

Traditional margin-line starburst patterns and etched corner accents designed for period Victorian sashes.
Level 4 Privacy
Modern Design

Float matt (Decormat)

Traditional margin-line starburst patterns and etched corner accents designed for period Victorian sashes.
Factory-Applied Protection

Architectural Palettes & Translucent Stains

Advanced 3-stage microporous spray finishes engineered to breathe with natural timber, extending maintenance cycles up to 8–10 years.

Chalk White

RAL 9010

Agate Grey

RAL 7038

Slate Moss

RAL 7009

Anthracite

RAL 7016

Cotswold Cream

RAL 1013

Dual-Colour Specification

Specify contrasting exterior and interior colours. Harmonise exterior brickwork with Anthracite while maintaining a soft, neutral palette indoors.

Translucent Wood Stains

UV-resistant, breathable oils and translucent stains allow the prominent grain of European Oak and Meranti to show through with complete protection.
High-Performance Sealed Units

Specialist Glazing Configurations

Thermally broken insulated glass units tailored to acoustic conditions, solar loads, and conservation standards.

Acoustic Laminate

Up to 44dB Cut
Asymmetric glass thicknesses with a PVB interlayer that disrupts noise resonance and traffic roar.
Road & Rail Coridoors

Solar Control

From 70/35
Microscopic coating reflects unwanted solar heat gain while preserving crystal-clear natural illumination.
South Elevations

Slimline Heritage

12mm–14mm Profile
Narrow gas-filled units engineered to fit traditional glazing bars for Conservation and Listed homes.
Conservation Areas

Passivhaus

0.8 W/m²K U-Value
Dual warm-edge cavity units delivering maximum thermal insulation for near-zero heat loss builds.
Passivhous Compliant
Stay Stylish With Matching Doors

Looking For Matching Timber Doors?

We have just the thing...
Check out our timber doors collection, from English front doors, to French and Bi-fold doors, Patio doors and Internal doors, we've got them all just a click away.
View Our Timber Doors
Company No: 08821594
Vat No:189597232
Created@keystone-supplies.co.uk
Keystone Supplies
Unit 17
Storforth Lane Trading Estate
Hasland
Chesterfield
Derbyshire
United Kingdom
S41 0QQ