Two-storey extension types compared

Side by side: what each type adds, a guide price, and how the planning rules treat it in each nation.

At a glance

Type	What it adds	Guide (W Mids)	Permitted development?	Best for
Two-storey rear	Kitchen-diner below, bedroom(s) above	£56,000–£75,500	England/NI: possible if no more than 3 m deep and 7 m from the rear boundary. Wales: 4 m ground floor, 3 m first floor, 10.5 m to the boundary. Scotland: only if 10 m from all boundaries.	Deeper gardens
Two-storey side	Extra width on both floors	£86,000–£115,500	England/NI: planning permission. Wales: possible with 10.5 m and 1 m set-back. Scotland: rarely.	Houses with a side driveway or gap
Wraparound	The most space: side and rear together	£120,500–£165,000	Planning permission almost always	Corner plots and wide gardens
Part single, part two	Wide ground floor, bedroom over part	£72,000–£99,000	Usually planning permission: in England and NI the whole extension must stay within 3 m once any part is two storeys	When upstairs space is needed only over part
Over a garage	A bedroom on an existing footprint	£31,500–£46,000	Usually planning permission (side two-storey)	Houses with a side garage
First floor over existing	A room on top of a single storey	£25,000–£36,500	Rear: treated as a two-storey rear extension	Houses already extended downstairs
Two-storey front	A bigger hall or porch with a room above	£26,500–£36,000	Always planning permission	Where front space is generous

Kitchen-diner below, bedroom(s) above

Extra width on both floors

The most space: side and rear together

Wide ground floor, bedroom over part

A bedroom on an existing footprint

A room on top of a single storey

A bigger hall or porch with a room above

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