Inside Our Factory: From Forest to Finished Window
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At Timber Sash Windows London, our passion for quality timber craftsmanship runs through every stage of our manufacturing process. From ethical wood sourcing to precision machining and flawless finishing, here’s how your bespoke windows come to life.
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1. Design & Specification
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Every project starts with careful design. Whether replicating original period details or creating something bespoke, our design team uses CAD and traditional joinery principles to ensure precision, beauty, and performance.
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In-house CAD drawings
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Traditional sash proportions & detailing
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Tailored to planning constraints & conservation requirements
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2. Sustainably Sourced Timber (FSC® Certified)
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We only use premium-grade timber from responsibly managed forests. Our timber — primarily engineered softwood, hardwoods like oak or sapele — is FSC® certified, guaranteeing full traceability and environmental stewardship.
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FSC®/PEFC certified suppliers
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Hand-selected for strength and stability
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Kiln-dried to optimum moisture levels for joinery use
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3. Precision Machining
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Once approved, components are milled using state-of-the-art CNC machines and traditional joinery techniques. This blend of technology and craftsmanship ensures accuracy and repeatability across even the most intricate profiles.
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CNC cutting & shaping
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Traditional mortise & tenon joinery
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Hand finishing and quality checks at every stage
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4. Pre-Assembly & Glazing
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Before painting, frames are dry-assembled and fitted with glazing units. This ensures airtightness and thermal performance — all in-house under strict quality control.
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Factory-fitted glazing (double/triple glazed)
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Fully sealed, drained & vented systems
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Slimline glazing bars available for conservation compliance
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5. Painting & Finishing
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Each window is factory spray-painted with high-performance microporous coatings. This guarantees even coverage and durability, far superior to brush painting on-site.
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3-coat spray system (primer + 2 topcoats)
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Any RAL or heritage colour available
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Factory finish ensures long life with minimal maintenance
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6. Final Assembly & Dispatch
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After painting, ironmongery is fitted and each unit undergoes final inspection. Products are then carefully wrapped and prepared for delivery or site installation.
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Why Our Factory Process Matters
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✅ Built to Last: Traditional craftsmanship meets modern precision
✅ Eco-Conscious: All timber responsibly sourced and waste minimized
✅ Performance Assured: Every unit fully tested for weather and acoustic sealing
✅ Ready to Install: Pre-finished, pre-glazed, delivered to your site