Whether a single storey extension needs planning permission depends on its size, height and position relative to the original house. Many projects fall within permitted development rights, which allow certain works without a full application.
When permitted development applies
Rear extensions up to a set depth, side extensions within width limits and heights under four metres can often proceed without permission. Limits differ for detached and semi detached properties, and previous extensions count towards your allowance.
It is always worth confirming your position with a lawful development certificate before starting work. This placeholder copy will be replaced with a reviewed article before publishing.
