Listed building consent is the route for any work that affects a listed building’s special character, and for windows it is a well trodden one. Historic England’s guidance is that new double glazing in historic windows usually goes through consent, and replacing a whole window always does. This guide shows how.
Listed building consent for windows: a specifier's guide
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No fee, and a decision within eight weeks
In England there is no fee for a listed building consent application, and a decision should be made within eight weeks of the application being validated. This guide covers what triggers consent, what to submit and how to present a glazing upgrade so the conservation officer has what they need.
Which work goes through consent
Consent comes from section 7 of the Planning (Listed Buildings and Conservation Areas) Act 1990. It applies to the whole building, inside and out, whatever its grade. About 91.7% of listed buildings in England are Grade II, about 5.8% are Grade II*, and about 2.5% are Grade I.
| Window work | Route |
|---|---|
| Like for like repair of timber and putty | Not usually, but check with the conservation officer |
| Draughtproofing | Not usually |
| Secondary glazing | Sometimes, where it affects shutters, panelling or historic joinery |
| Replacing glass with slim double or vacuum glazing | Usually, through listed building consent |
| Replacing the window | Listed building consent |
Before you apply
Talk to the local authority’s conservation officer first. Historic England and the Planning Portal both recommend pre application advice, and an early site visit often settles whether new glass will be acceptable in principle.
Bring a condition survey of the windows. It should show which sashes and panes are original, whether any historic glass survives, and the condition of the frames. Historic England’s guidance is to keep early glass where possible, so the survey shows which windows are ready for new glass.
What to submit
| Document | What it should show for a glazing upgrade |
|---|---|
| Location plan and site plan | The building and the elevations affected |
| Design and access statement | The proposal and why it is needed |
| Heritage statement | The significance of the windows and the effect of the change |
| Window schedule and condition survey | Each window, its glass, its condition and the proposed work |
| Section drawing | The new unit in the existing rebate, with sightlines and the bead or putty detail |
| Manufacturer’s data | Datasheet, Declaration of Performance and CE marking for the glass |
Applications in England go through the Planning Portal or the local authority. The eight week clock starts once the application is validated.
Making the case for vacuum glazing
The strongest applications show how well the window keeps its character. Fineo 8 is 7.7mm thick, close to the thickness of the original glass, so it can go into the existing sash without cutting back the rebate or remaking the joinery. A section drawing showing the unit in the original rebate makes that point better than any description.
Address appearance directly. Fineo is a single sheet of glass to the eye, without the double reflection of a thicker unit. Where the elevation calls for it, Fineo Heritage reproduces glass from the 1880s to the 1960s. Then give the performance: a Ug of 0.7 W/m²K, Rw 35 dB, and CE marking under ETA 20/0048.
Reference projects help. Fineo has been fitted in listed buildings including Watford Town Hall, Egyptian and Dudley House on Piccadilly and the Royal Observatory Edinburgh.
Isometric section, explodedViewed from outside
Not to scale. Thickness is enlarged so each layer can be seen; the pillar grid is shown sparser than the real 20mm spacing.
Fineo 8 at a glance
- Total thickness
- 7.7 mm
- Ug value
- 0.7 W/m²K
- Light transmission
- 79 %
- Solar factor g
- 0.61
- Sound Rw (C;Ctr)
- 35 (−2;−5) dB
Thickness to scale
Each bar is drawn to the same scale. Fineo shows its two panes and the 0.1mm vacuum between them. A lower U-value means less heat lost through the glass.
GlazingThicknessU-value
Single glazing 4mm5.8
Fineo 8 7.7mm0.7
Slim double 11mm1.9
Double glazing 28mm1.2
Triple glazing 36mm0.8
Scotland, Wales and Northern Ireland
In Scotland, apply to the planning authority, which must consult Historic Environment Scotland on certain applications. Listed buildings are in categories A, B and C. In Wales, local planning authorities handle consent, Cadw oversees the process, and a heritage impact statement is required. In Northern Ireland, consent comes from the council, advised by the Historic Environment Division of the Department for Communities.
Building regulations
Listed building consent and building regulations are separate. Replacing only the glass in an existing frame is not normally controlled under the Building Regulations, while replacing the whole window is. Our guide to Part L and listed building windows covers the detail.
Frequently Asked Questions (FAQs)
Do I need listed building consent to replace the glass in sash windows?
Usually, yes, and the application is free in England with a decision due in eight weeks. A condition survey, heritage statement and section drawing give the officer what they need.
How much does listed building consent cost?
In England there is no fee for a listed building consent application.
How long does listed building consent take?
A decision should be made within eight weeks of the application being validated.
Will a conservation officer approve vacuum glazing?
Fineo is already fitted in listed buildings such as Watford Town Hall and the Royal Observatory Edinburgh. The strongest applications show the glass is not historic, the sash is sound and the unit fits the original rebate.
What drawings do I need for a glazing application?
A window schedule, a condition survey and a section drawing of the new unit in the existing rebate, alongside the heritage statement and the manufacturer’s datasheet.
Approved by RIBA and IHBC
Fineo is approved by both the Royal Institute of British Architects (RIBA) and the Institute of Historic Building Conservation (IHBC). Our free seminar on vacuum glazing for heritage and conservation projects carries the backing of both bodies, and the time your practice spends with us counts towards CPD.
Consent, made clearer
Download the Fineo datasheets and Declarations of Performance for your application, or book a free CPD on vacuum glazing in listed buildings.