Planning, explained straight

Almost every London extension, loft and basement engages this Act. Here's how it actually works.

If your home is listed, planning permission is only half the story.

Your lease is a contract — and the council was never the only gatekeeper.

Permitted development is a houses-only system. If you own a flat, the rules — and the consents — are different.

Two separate approval systems. Confusing them is the most common — and most expensive — mistake in domestic building.

Building regulations are a separate system from planning — and the certificate at the end is the one your buyer's solicitor will ask for.

The right people, in the right order. Most overspend starts with hiring the wrong one — or hiring them too late.

Most expensive mistakes aren't bad decisions — they're the right ones made in the wrong order. Here's the sequence, start to finish.

The size limits, the exceptions, and the postcode-level traps.

Bigger single-storey rear extensions without a full planning application — but it's a notification process, not a free pass.

Real ranges from real projects — not brochure numbers.

40 cubic metres of opportunity — unless your street says otherwise.

Four roof forms, four budgets — and one big conservation premium.

VAT is the quiet 20% on top of almost everything — and the loft-conversion zero-rating myth is the one that wrecks budgets.

The value isn't a single price — it's the range, and the red flag. Expect £X–£Y; a quote far below the field almost always excludes something.

Designated land edits the rulebook — here's the exact redline.

Permitted development is only worth anything if you can prove it. A lawful development certificate is that proof.

Built without permission? The enforcement timeline changed fundamentally in 2024 — and most advice online is still wrong about it.

The designation nobody's heard of until it refuses their extension.

The C3-to-C4 shortcut is gone across much of London — check the borough, then the address.

Sixty seconds of checking saves weeks of redesign.

No permission needed — provided you respect five precise rules.

The biggest space gain in London — bought at the steepest price.

Most home extensions pay no CIL. The ones that do almost always do so because of a missed form, not a real bill.

The public record is your best planning consultant — if you can read it.

A refusal is a set of reasons, not a full stop. The reasons tell you which of three routes to take.

Find out what you can build before you commit, not after.