— Specialism · 07 / 08

Sash windows in
conservation areas.

London has 1,033 conservation areas. Replacing windows in any of them needs an approach that keeps the streetscape intact — and an installer who knows the rules.

— Conservation rules

What you can,
what you cannot.

Conservation area rules differ from listed-building rules — less restrictive, but with crucial details that catch out non-specialist installers.
  1. 01

    Article 4 directions

    Many CAs have an Article 4 removing permitted-development rights for windows.

  2. 02

    Like-for-like

    Most CAs allow timber sash replacement that matches the original profile.

  3. 03

    No uPVC

    Plastic windows almost never get permission in a CA. Do not try.

  4. 04

    Front matters most

    Rear elevations have more flexibility — sometimes.

  5. 05

    Group value

    Even an unlisted building in a CA can have group value — means stricter rules.

  6. 06

    Enforcement

    Councils do enforce — recent London cases reversed at owners expense.

— CA application process

Most CAs:
no consent needed.

For a like-for-like timber sash replacement, most London conservation areas allow the work without a separate planning application — provided the work is genuinely like-for-like.
  1. 01
    Article 4 check

    We confirm whether your CA carries an Article 4 direction.

  2. 02
    Profile match

    Existing window measured and replicated to 1mm tolerance.

  3. 03
    Glazing

    Slim-line double glazing approved in 95%+ of London CAs.

  4. 04
    Paint

    Heritage colours only — no contemporary RAL.

  5. 05
    Application (if needed)

    Householder planning application, 8-week determination.

  6. 06
    Records

    Drawings filed for next owner — future-proofing.

— Conservation FAQ

Common questions about
conservation.

Search your postcode at planning.data.gov.uk — or ask us, we have boundary maps for every London CA.

It is a council instruction that removes permitted-development rights. In windows context, it means even a like-for-like replacement needs planning permission. Common in Hampstead, Bedford Park, Highgate.

Almost always yes, if the slim-line profile matches the original. We have approved double-glazed installs in 33 London boroughs.

— Ready to start?

Free survey,
fixed quote.

Tell us about the property and we will come back within one working day with a window count, indicative price and the next available survey slot.

Workshop Unit 12, Park Royal,
London NW10 7XF
Service area All London boroughs
+ M25 corridor