The seven planning pitfalls that delay home extensions

The seven that catch people out

• Article 4 directions — some councils remove permitted development rights street-by-street. Check before you design.
• Conservation areas & listed buildings — PD is curtailed or gone; expect full planning and conditions.
• Depth limits — rear extension depth allowances are finite and the larger-home prior-approval route has a neighbour-consultation step.
• Height & eaves — exceeding the eaves/ridge rules near a boundary fails PD instantly.
• Side returns on the boundary — a Party Wall Act notice to the neighbour is separate from planning and adds weeks.
• Previous extensions — earlier additions count against your remaining PD allowance.
• Flats & maisonettes — permitted development for extensions generally doesn't apply.

Do this first

Get a Lawful Development Certificate if you're relying on permitted development — it's proof, not a formality, and a buyer's solicitor will ask for it later.

Budget the Party Wall surveyor and building-control fees as line items, not afterthoughts.