Wood window manufacturing: A behind-the-scenes look for builders and architects

Some of the most important considerations for wood window manufacturing are precision, consistency, and material integrity. For architects and building contractors specifying performance-led fenestration, understanding how timber windows are made can significantly influence product choice, installation planning, and long-term building performance.

For over a decade, GB Joinery has been at the forefront of premium timber window production, combining expert craftsmanship, modern CNC technology, dependable turnaround times, and exceptional customer support. This behind-the-scenes blog reveals exactly how our specification-grade windows are created, from sustainably sourced timber to final inspection.

Responsible timber sourcing – FSC® and PEFC-certified materials

Every high-performance wood window begins with the right raw material. At GB Joinery, we source FSC® and PEFC-certified timber, ensuring full chain-of-custody traceability and sustainable forest management.

Timber species selection

Different projects require different wood characteristics. At GB Joinery, we commonly work with:

• Accoya – ultra-stable, modified timber perfect for precision joinery.
• Oak – strong, durable, and ideal for heritage installations.
• Hardwoods like sapele – ideal for premium, long-lasting window frames.

These species provide the dimensional stability, durability, and low thermal conductivity essential for modern fenestration.

Moisture testing and warping control

Before a single component is machined, timber moisture content is checked using calibrated moisture meters.

Why moisture levels matter

• Prevents future warping, twisting, and cupping
• Ensures accurate milling
• Reduces risk of joint movement
• Supports long-lasting paint adhesion

GB Joinery’s timber is conditioned to industry-recommended moisture levels, guaranteeing stability throughout the manufacturing process.

Milling and CNC machining – precision at every stage

Modern CNC machinery allows the team at GB Joinery to combine traditional craftsmanship with digital accuracy.

Milling profiles

Timber is planed and profiled into frame components using:

• High-speed spindle moulders
• Multi-axis CNC routers
• Automated cutters for replication accuracy

This ensures perfectly matched sash profiles, casement frames, and tilt & turn components across repeat orders, ideal for phased developments.

Benefits of CNC-led manufacturing

• Consistent tolerances
• Reduced waste
• Faster turnaround times
• Repeatable accuracy for large-scale contractor orders

This level of precision is essential for architects working with tight tolerances or bespoke detailing.

Joinery assembly – traditional craftsmanship meets engineered strength

Once profiled, components move to the assembly department where skilled joiners carry out:

• Mortise and tenon joints
• Dowelled frames
• Laminated sections for improved stability

Structural integrity checks

Before windows advance to finishing, joiners inspect:

• Corner alignment
• Joint compression
• Operational smoothness for sashes, casements, and tilt & turn mechanisms

This stage ensures each frame meets the structural demands of modern building regulations.

In-house finishing – coatings that protect and perform

One of the biggest advantages of GB Joinery’s facility is its in-house finishing department.

Factory finishes include:

• Micro-porous paints
• High-performance stains
• Multi-layer coatings for weather protection

Why factory finishing matters

• Uniform coating thickness
• Longer-lasting protection
• Better adhesion
• Reduced site labour

Professionals benefit from windows that arrive ready to install, with optimal durability and aesthetic consistency.

Glazing and hardware installation

The glazing stage uses thermally efficient sealed units, tailored to the project’s requirements:

• Double or triple glazing
• Acoustic glass
• Low-E coatings
• Laminated security panes

Hardware integration

Premium hardware including friction stays, sash balances, and locking systems ensures:

• Smooth operation
• Enhanced security
• Compliance with PAS 24 and Part Q

Hardware is tested before dispatch to guarantee flawless performance on-site.

Quality control and specification compliance

GB Joinery’s rigorous quality control process acts as the final checkpoint before dispatch.

Inspection criteria include:

• Dimensional accuracy
• Paint finish quality
• Glazing bead fit
• Air-tightness standards
• Smooth operation checks

Every window is manufactured to meet or exceed Part L, Part Q, and relevant British Standards, giving specifiers total confidence in compliance.

Why professionals trust GB Joinery

For over 10 years, GB Joinery has consistently delivered:

• Premium timber window manufacturing
• Specification-compliant performance
• Reliable lead times
• Outstanding customer service
• A blend of technology and craftsmanship that sets us apart

Architects and contractors value GB Joinery’s ability to produce high-performance, aesthetically refined timber windows tailored to demanding project requirements.

If you’d like to find out more about working with GB Joinery, get in touch today. For more information about any of our products or services call 0161 477 1818 or send us a message online and we’ll get back to you as quickly as possible.