Replacing windows without planning permission in Kensington and Chelsea: what changed in October 2025

By Denis Kvasnei · June 29, 2026 · 9 minute read

TLDR

What changed on 23 October 2025

Replacing windows without planning permission in Kensington and Chelsea became possible on 23 October 2025. On that date the Royal Borough of Kensington and Chelsea, the council known as RBKC, confirmed a Local Development Order for window alterations in non-listed buildings across the whole borough. A Local Development Order is a tool that grants planning permission in advance for a defined type of work, so no individual application is needed.

The direct effect is simple. A compliant window replacement in a non-listed home no longer needs planning permission. That holds in conservation areas as well as everywhere else in the borough.

Three things make this notable.

First, RBKC says it is the only place in the country to allow new windows without planning permission, even in conservation areas.

Second, it gives flats and houses in multiple occupation the freedom that whole houses already had under permitted development, which is the set of works the law lets you carry out without a planning application. It does this by overriding the Article 4 directions that had taken that freedom away. An Article 4 direction is a local order that removes permitted development rights in a defined area.

Third, the order follows the council's own numbers. In 2024 RBKC decided 85 window applications on non-listed buildings. It granted 79. The six it refused or saw withdrawn were each about the window being the wrong material. RBKC concluded the planning step added limited value here. So the order removes a form that was, in practice, checking for one thing.

Who and what it covers

The order covers non-listed residential property across the borough. That means flats, houses, and houses in multiple occupation. It does not matter whether a flat is purpose-built, carved out of an older house, or sits above a shop in a mixed-use building.

The core condition is similar appearance. The new window must be of similar appearance to the one it replaces. Similar appearance means the same material, style, pattern and design, with only minimal differences in frame size and glazing-bar profile. A glazing bar is the slim strip that divides a window into separate panes of glass.

There is one exception to that test, covered in the next section: similar appearance does not apply when you replace uPVC, a plastic window frame, with timber.

Single glazing to double glazing is allowed, as long as the material stays the same.

Upper floors carry extra conditions. On the first floor and above, including dormers, which are windows that project from a sloping roof, two rules apply. A window that is currently obscure-glazed must be replaced with obscure glazing to an equivalent specification. A window that does not open must stay non-opening, unless its opening parts sit more than 1.7 metres above the floor.

Those are summaries. For the full conditions, read the order itself and Part 3 of the Planning Register, not the Householders' Guide, which only defines what similar appearance means.

The material rule, the one direction you cannot go

The order treats window materials as a one-way street.

Replacing uPVC with timber is allowed without a separate planning permission. This is the single case where the similar-appearance test is relaxed, because you are improving the material rather than matching it.

Replacing timber with uPVC always needs planning permission. There is no version of that move the order permits.

Swapping like for like is fine where it meets the similar-appearance test. Timber for timber and uPVC for uPVC are both allowed, as long as the new window matches the old one closely enough.

The logic is plain. The order lets you move toward traditional materials, not away from them. RBKC's own analysis supports this. Across its 2024 figures, the only window applications it refused were for the wrong material. Material was the one thing the old planning step reliably caught, so the order kept that filter and dropped the rest.

If you take one rule from this article, take this one. Check the material direction before you order anything. Getting it right is cheaper than getting it wrong, and it is the easiest of all the conditions to settle before any glass is ordered.

What the order does not remove

The order removes one form. It leaves several rules standing.

Listed buildings are out of scope completely. If your building is listed, window works that affect its fabric still need listed building consent, which is a separate permission to alter a building of special historic or architectural interest. The order does nothing for you here. If you are unsure how listing changes the picture, our guide to what listed status changes sets it out.

The order covers replacement only. It does not cover enlarging an opening, creating a new opening, doors of any kind, rooflights, or conservatories. It does not let you fit a mirrored window in place of clear or obscure glass, or add reflective film that changes how the window reads from outside.

Materially altering the external appearance of a building that contains flats still needs planning permission in its own right. The order only covers replacement that keeps the appearance the same.

Building Regulations still apply. These are the national standards for safety and performance, covering safety glazing, thermal performance, ventilation and means of escape. A window that satisfies the order can still fail Building Regulations.

Freeholder consent still applies where your lease requires it. This is the freeholder's permission to carry out the work. For a flat in a converted townhouse, this is now the permission that matters most, because it is the one the order does not touch.

On process, there is no need to tell the council and no planning fee. If you want certainty, which is useful when you come to sell, you can apply for a Certificate of Lawful Development. This is a formal confirmation, for the usual fee, that the work falls within the order.

Kensington and Chelsea only: Mayfair, Belgravia and Marylebone are different

This is an RBKC order. It applies in Kensington and Chelsea and nowhere else.

It does not apply in Westminster. Mayfair, Belgravia and Marylebone all sit in the City of Westminster, a separate planning authority with its own rules. There, the old position still holds. A change to a flat's windows can still need planning permission. Conservation-area controls still apply, and Article 4 directions still bite.

So the same window, in the same kind of conservation area, can get two different answers depending on which side of a borough boundary it sits.

A flat on one street in Kensington can have its windows replaced with no application at all. A flat of the same age and type a short distance away in Belgravia may need a full planning application for the identical change.

Check which council you are in before you order glass. The address sets the rule, not the building. The boundary is not always obvious on the ground, so confirm it against the council's own maps rather than assuming from the postcode.

The mistake to avoid

The trap is reading this order as "any new window, anywhere in Kensington and Chelsea." It is not that.

Three things still send you back to the planning route: the wrong material direction, a listed building, or a design that changes how the window reads from the street. Get any of them wrong and the council can serve an enforcement notice, which is a legal demand to put the work right. In practice that can mean taking the new windows out and fitting them again.

No permission needed is not the same as no rules. Building Regulations and freeholder consent both still apply.

There is an industry habit worth naming. A construction manager who reads "permitted" as "unsupervised", who skips the appearance test, the material rule and Building Regulations because no planning form is required, is part of that problem, Myrmex included. The form going away does not remove the judgement that has to sit behind the work.

That is the real point. The order removes the application, not the thinking. Decide the window against the appearance test and the material rule before you buy the glass, not after it is in the frame. If you want a clear view of how a window project should be run from the first decision, that is the next thing to read.

FAQ

Frequently asked questions

I replaced my windows the wrong way before the order. Am I covered now?

No. The order is not backdated. It does not make past non-compliant work lawful. If your old replacement broke the rules that applied then, the council can still act on it. You may need to apply for permission after the event. Or you can apply for a Certificate of Lawful Development, which formally confirms work is lawful, if the work would meet the current order. The order changes what you can do next, not what you already did.

Q.01

How do I prove to a buyer that my new windows were allowed under the order?

Apply for a Certificate of Lawful Development. Because you never had to notify the council, there is no application or decision on record to point to. The certificate is the one document that confirms the work fell within the order. A buyer's solicitor will look for exactly this during conveyancing, the legal process of transferring the property. Without it, you are asking the buyer to take your word.

Q.02

Could my new double glazing still count as changing the appearance and need permission?

Yes. Double glazing itself is allowed if the material stays the same. But the order looks at how the finished window reads, not only at the glass. If the new unit changes the glazing-bar pattern, the proportions, or the way it opens, it can read differently from the street. At that point it is no longer a similar-appearance replacement, and it needs planning permission like any other change of appearance.

Q.03

Does the order cover shopfront or commercial windows?

No. The order is for residential property only: flats, houses and houses in multiple occupation. Shopfronts and other commercial windows fall outside it. In a conservation area, those windows follow the normal planning route, and a shopfront often carries its own separate controls. A mixed-use building can hold both at once: the flats above can fall under the order while the shop at street level does not.

Q.04

How long will the window LDO last?

No fixed end date. RBKC intends the order to run for an indefinite period. The council can revise or revoke it at any time. If it were revoked, window changes would return to the old planning route. Until then, a replacement that meets the conditions needs no planning permission. There is no renewal date to track and no expiry to plan a project around.

Q.05

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