What Extensions Have My Neighbours Had Approved Nearby? A 2026 Guide for UK Homeowners

Stand in your back garden for five minutes and you can probably see it: next door's new kitchen extension, the loft conversion two doors down, that side return the family across the road finished last spring. If you're thinking about extending your own house, those extensions aren't just nosy-neighbour material. They're a genuinely useful starting point for working out what you might be able to build, how big it could be, and whether you'll need full planning permission or can rely on permitted development rights.

This guide explains how to use "what have my neighbours had approved nearby" as a practical research question, not just idle curiosity, and how to read that information correctly so it actually helps your own extension plans in 2026.

Why Checking Nearby Extensions Matters Before You Design Anything

Every extension application that gets approved (or refused) near you leaves a public record. Taken together, those records tell a story about how your local planning authority actually behaves on your street, not just what the national rules say in theory. A council might be strict about side extensions in a conservation area but relatively relaxed about single-storey rear extensions on non-designated land two roads over. Knowing that before you commission drawings or speak to an architect can save weeks of redesign and thousands of pounds in wasted fees.

There are three practical reasons to look at what's already been approved nearby:

1. It shows you realistic scale. If several houses on your road similar to yours have had single-storey rear extensions approved at a certain depth, that's a strong signal of what's likely to be acceptable, whether under permitted development or via a planning application.
2. It reveals local sensitivities. Refusals (and the reasons for them) tell you what the council pushes back on, whether that's loss of light to a neighbour, overdevelopment of a plot, or materials that clash with the street scene.
3. It helps you plan your own timeline and budget. Seeing how long similar applications took to decide, and whether they went through as permitted development or needed a full application, gives you a realistic sense of what lies ahead.

How to Find Out What Extensions Have My Neighbours Had Approved Nearby

Every local planning authority in the UK maintains a public planning register, usually searchable online through the council's planning portal. You can typically search by street name, postcode, or application reference, and view submitted plans, decision notices, and any conditions attached to the approval.

When you're reviewing nearby approvals, look beyond just "approved" or "refused." The useful detail is in:

• The application type. Was it a full planning application, a certificate of lawful development (confirming permitted development rights), or a prior approval submission?
• The plans and elevations. These show you the actual depth, height, and footprint of what was built, not just a headline description.
• Conditions attached. Many approvals come with conditions on materials, obscure glazing to protect neighbour privacy, or restrictions on further development.
• The date. Planning policy and permitted development rights have changed over the years (most recently with the addition of rules allowing extra storeys on existing houses), so an approval from ten years ago may not reflect what's currently allowed.

This is where a lot of homeowners get stuck. Council portals are built for planning professionals, not for someone trying to work out whether their own extension is likely to be approved. Cross-referencing multiple nearby applications, understanding which rules applied at the time, and translating that into "so what does this mean for my extension" is genuinely time-consuming if you're doing it as a one-off.

Reading Neighbour Precedent Correctly: Permitted Development vs Planning Permission

This is the single most important distinction to grasp when you're looking at what's been approved nearby. Not every extension you see went through a planning application at all.

Many single-storey rear extensions are built under permitted development rights, meaning no planning application was needed, only (in some cases) a certificate of lawful development to confirm it. Under the standard permitted development limits, a single-storey rear extension can extend up to 4 metres beyond the original rear wall for a detached house, or 3 metres for a semi-detached or terraced house, with a maximum height of 4 metres. These are measured from the base of the original rear wall to the outer face of the new extension wall, not including guttering.

Go bigger than that, and the extension moves into "larger home extension" territory: up to 8 metres beyond the rear wall for a detached house, or 6 metres for any other house (still capped at 4 metres in height), but only if the house isn't in a conservation area or on similarly designated land. These larger extensions require the neighbour consultation scheme, where the council writes to adjoining neighbours, who have the chance to object. Work can't start until the council either confirms no approval is needed, grants prior approval, or 42 days pass without a decision.

So when you see a big rear extension on a nearby house, it's worth understanding which route it took. Was it within the standard permitted development limits, was it a larger one through neighbour consultation, or did it need a full householder planning application because it exceeded even those limits? Each tells you something different about what's realistically achievable on your own house.

Just Bought a House and Want to Extend? Start With What's Already There

If you've recently moved in and are already picturing a bigger kitchen or an extra bedroom, resist the urge to jump straight to an architect. New owners often assume that because a neighbour's extension looks similar to what they want, it's automatically permitted development on their own house too. That's not always true, because permitted development rights depend on specifics: whether your house is detached, semi-detached, or terraced, whether it sits on article 2(3) land (conservation areas, National Parks, AONBs, the Broads, or World Heritage Sites), whether previous extensions have already used up some of your allowance, and whether your original rear wall is even where you think it is.

"Original" is a key word here. Under permitted development rules, measurements are taken from the house as it was first built (or as it stood on 1 July 1948), not as it stands today. If a previous owner already added a rear extension, your remaining permitted development allowance may be smaller than you'd expect, or used up entirely.

This is exactly where checking nearby approvals becomes useful groundwork, but it's not a substitute for finding out your specific property's planning history and current permitted development status. A house two doors down might look identical from the street but have a completely different planning history to yours.

Common Extension Types Neighbours Have Had Approved

Single-Storey Rear Extensions

The most common extension by far. Within the standard limits (4 metres detached, 3 metres other house types, 4 metres height), these usually don't need planning permission at all, just confirmation via a certificate of lawful development if you want it in writing for future buyers or mortgage lenders. Beyond those limits, up to 8 metres (detached) or 6 metres (other houses), the neighbour consultation scheme applies.

Wraparound Extensions (Side and Rear Combined)

Where a homeowner extends both to the side and across the rear to fill in the whole corner of the garden, the rules for rear depth still apply (up to 6 metres or 8 metres detached, outside conservation areas), the extension must remain single storey and no higher than 4 metres, and the total width of the extension is capped at half the width of the original house. These are popular for creating open-plan kitchen-diners, and you'll see plenty of examples on suburban streets built in the 1930s to 1970s where side access allows it.

Upward Extensions (Extra Storeys)

Since 2020, homeowners have had a route to add storeys on top of an existing house under permitted development, provided the house was originally built between 1 July 1948 and 28 October 2018. A single-storey house can gain one additional storey; a house with two or more storeys can gain up to two additional storeys. The finished house must not exceed 18 metres in height, each new storey is capped at 3.5 metres, and for terraced or semi-detached houses the new roofline can't exceed the neighbour's by more than 3.5 metres. This route always requires prior approval from the council, even though it sits under permitted development, and it doesn't apply in conservation areas or to listed buildings. If you've noticed a neighbour's house has visibly grown an extra floor in the last few years, this is very likely how it happened.

Side Extensions

Common on detached and some semi-detached houses with side access, though these are far more restricted in conservation areas (more on that below). A single-storey side extension not exceeding half the width of the original house, kept under 4 metres in height, can often be permitted development outside designated areas.

Conservation Areas: Why Your Neighbour's Extension Might Not Apply to You

If your street sits within a conservation area, National Park, AONB, the Broads, or a World Heritage Site, be cautious about assuming a neighbour's extension sets a precedent for permitted development rights on your own house. On this kind of designated land, permitted development is noticeably more restricted:

• The larger rear extension allowances (up to 8m/6m) do not apply at all.
• Side extensions are not permitted development, full stop, regardless of size.
• A rear extension of more than a single storey is not permitted development.
• Cladding or rendering the exterior in stone, artificial stone, pebble-dash, render, timber, plastic, or tiles is not permitted development.

So if you see a rendered two-storey side-and-rear extension on a neighbouring conservation area property, it almost certainly went through a full planning application, and quite possibly attracted objections or conditions along the way. That's useful information, but it tells you that you'll likely need planning permission too, not that the work is automatically achievable.

Do I Need Planning Permission for My Extension?

As a quick gut check, you're more likely to need a full planning application rather than relying on permitted development if:

• Your extension would go forward of the principal elevation of the house, or forward of a side elevation that fronts a highway