The Complete Guide to Secondary Glazing for Listed Buildings

Installing secondary glazing in a listed building requires careful consideration of heritage requirements, planning regulations, and aesthetic sensitivity. This comprehensive guide covers everything you need to know.

Understanding Listed Building Regulations

Listed buildings in England are protected under the Planning (Listed Buildings and Conservation Areas) Act 1990. Any alterations that affect the building's character require Listed Building Consent (LBC).

The good news? Secondary glazing is typically considered a reversible alteration that doesn't permanently modify historic fabric. In most cases, it can be installed without requiring Listed Building Consent, though we always recommend consulting with your local conservation officer first.

Why Secondary Glazing is Heritage-Friendly

• Reversible: Can be removed without damaging original windows
• Preserves character: Original windows remain visible and intact
• Minimal intervention: No structural modifications required
• Maintains authenticity: Historic glass and frames preserved

Design Considerations

When specifying secondary glazing for listed buildings, several design factors are crucial:

Frame Profiles

Slim-line aluminium profiles are preferred as they minimise visual impact. We typically use frames as narrow as 20mm, powder-coated to complement existing window colours.

Glazing Options

Clear glass is essential to maintain views of original window details. We can match heritage glass weights and use low-iron glass to eliminate green tints.

Opening Mechanisms

Secondary glazing must allow access to original windows for ventilation and maintenance. Lift-out panels, hinged casements, and horizontal sliders are all viable options.

The Application Process

While LBC isn't usually required, we recommend this process:

1. Consult your local conservation officer informally
2. Document existing windows photographically
3. Obtain technical specifications from your installer
4. Submit for informal approval if requested
5. Proceed with installation
6. Retain documentation for property records

Get Expert Advice

Our heritage specialists have extensive experience working with listed buildings across London. Contact us for a free consultation and heritage assessment.