In 40 seconds
A garden shed in the UK typically costs roughly £500 for a small 6x4 model up to £3,500+ for a large pressure-treated build, with a mid-range timber shed commonly around £800–£1,500 before the base and fitting. A base usually adds £100–£800 depending on whether you choose a plastic grid, paving slabs or a poured concrete pad. For most gardens a shed is permitted development and needs no planning permission, provided it stays single-storey, sits no higher than 2.5m at the eaves within 2m of a boundary, covers no more than half the garden, and is not in front of the house. A well-maintained wooden shed typically lasts 15–20 years, and 20–25+ with pressure-treated timber. The honest answer is always a range, because it depends on size, base and material.
Most shed guidance is published by companies selling sheds, so the numbers tend to be optimistic and the rules glossed over. The pages below give honest cost ranges, explain what a base really costs, compare a summerhouse with a shed fairly, set out the planning rules for outbuildings, and say how long the timber lasts — before you take a single quote.