Traditional Window Glazing

Traditional putty glazing has been used for centuries and remains one of the most trusted methods of installing glass into timber windows. In this project, our experienced joiner demonstrates the process of glazing a timber sash window using linseed oil-based putty—a technique that continues to be widely used throughout London, particularly on period and heritage properties.

Many of the original single-glazed timber windows found across London were glazed using linseed oil putty. From Georgian and Victorian townhouses to Edwardian homes, the distinctive angled putty line is a defining feature of traditional timber windows and an important part of their historic character.

The Glazing Process

Each pane of glass is carefully positioned before the linseed oil putty is applied by hand. The putty secures the glass, forms a weather-resistant seal, and creates the traditional chamfered finish seen on original timber windows.

Unlike modern glazing systems, this is a skilled manual process that relies on years of experience. Achieving perfectly straight putty lines and a consistent finish requires precision, patience, and craftsmanship.

As linseed oil putty is a natural product, it requires time to cure. Under normal conditions, it typically takes around four weeks to dry, although this can vary depending on temperature and humidity. Once fully cured, the putty is painted to match the window. The paint not only provides a seamless finish but also protects the putty from the weather, helping to maximise its lifespan.

Why Choose Putty Instead of Timber Glazing Beads?

Although timber glazing beads are commonly used in modern joinery, traditional putty glazing offers several important advantages, especially for period and heritage properties.

One of the biggest benefits is appearance. Putty creates a continuous, elegant finish around the glass without visible joints, mitres, pins, or fixings. This clean detail closely matches the original construction of historic windows and is often the preferred choice for conservation projects.

Putty glazing also provides excellent flexibility for maintenance. Over time, if the putty begins to weather, it can often be repaired or replaced while preserving the original timber window, rather than replacing glazing beads or altering the window’s traditional profile.

Another advantage is the slim glazing sightline that putty creates. This allows more of the glass to be visible and maintains the delicate proportions that make traditional timber windows so distinctive.

A Craftsmanship That Takes Time

Traditional putty glazing is considerably more labour-intensive than installing timber glazing beads.

Every section of putty is applied, shaped, and finished entirely by hand. There are no shortcuts or automated processes. The quality of the finished window depends entirely on the skill of the craftsman.

For this reason, windows glazed with traditional linseed oil putty generally cost more to manufacture than bead-glazed windows. The additional cost reflects the time, expertise, and attention to detail required to achieve an authentic finish. While modern glazing beads can be installed relatively quickly, traditional putty glazing is a specialist craft that values quality over speed.

The Preferred Choice for Stained Glass

Linseed oil putty is also the traditional choice for installing stained and leaded glass panels. Its flexibility and weather-resistant properties make it ideal for securing delicate stained glass while maintaining the authentic appearance of heritage windows. This is why it continues to be widely used by craftsmen working on churches, listed buildings, conservation projects, and period homes.

Preserving London’s Architectural Heritage

Walk through almost any historic street in London and you will see thousands of original single-glazed timber windows still glazed with linseed oil putty. Many have remained in service for decades thanks to regular maintenance and repainting.

Traditional putty glazing is more than just a method of installing glass—it is an important part of preserving the character, craftsmanship, and authenticity of Britain’s historic timber windows. While it requires more time and skill than modern alternatives, the finished result reflects the quality and heritage of traditional joinery, ensuring these beautiful windows continue to enhance our buildings for generations to come.

Looking for better energy efficiency? While putty glazing is perfect for single-glazed heritage windows, we also specialise in upgrading period properties with traditional double-glazed sash windows, blending modern thermal performance with classic architectural charm.