Summary

Traditional timber and metal windows can almost always be repaired, even when in poor condition. This option is normally significantly less costly than window replacement. Importantly, it is the most straightforward way of maintaining the visual character and architectural heritage of the building.

Window repairs should be made before any additional works such as secondary glazing is installed. Draught proofing is advised alongside window repair to further improve performance and reduce heat loss.

Cost/difficulty

LOW COST

MEDIUM DIFFICULTY

Applicability in Letchworth

Applicable – No specific requirements.

In Letchworth, windows contribute significantly to the historic identity and value of the homes. They are also an important factor in the appearance of groups of houses and the street scene.

Use natural finishing materials if possible. Avoid harsh chemical strippers or fillers. Reusing and restoring original windows preserves heritage value and limits environmental impact. 

The Heritage and Modern Character Area and Design Principles state that:

Repair of original windows with materials matching the original design is generally preferable, which can be assisted by the introduction of secondary glazing.

Insights from ASBP

“Window repair is a truly ‘circular’ approach and more environmentally friendly than recycling. As a general rule, explore how existing features and materials can be repaired or reused before replacing with new.”

Case study

Links to further information

• Energy Efficiency Guide for Letchworth Garden City residents (2024), page 3
• Energy Efficiency and Historic Buildings – Secondary Glazing for Windows (2016), page 5

Image credits – Steico

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This guidance is part of Windows and Doors

See more guidance notes on this topic below:

• High-performance triple or double glazing
• Secondary glazing
• Thick curtains and thermal blinds