Do You Need Planning Permission for a Garden Room in 2025?

80% of garden rooms DON'T need planning permission under Permitted Development Rights. Key rules: max 2.5m height within 2m of boundary OR 4m elsewhere, single storey only, can't cover over 50% of garden including all structures, not in front garden. Conservation areas have special restrictions requiring permission for side-facing structures or over 10m². Listed buildings ALWAYS need Listed Building Consent. Article 4 directions remove PD rights in specific areas. Certificate of Lawfulness (£206) provides legal certainty. Building Regulations separate requirement. Common mistakes: assuming timber equals permitted, trusting builder advice, forgetting previous extensions count toward 50% rule. Includes checking step-by-step guide and real Surrey examples from Guildford, Farnham, and Esher.