Well, it depends…
In the UK, usually you don’t need planning permission because putting up a shed or outbuilding is classed as ‘permitted development’ which allows outbuildings up to a certain size to be built without planning permission.
However, do check with your local council – for example where I live, permitted development rights have been revoked, meaning you have to apply for permission (but not full planning permission) from the council, although with a shed, nobody will probably mind – it’s mainly there to control inappropriate conservatories and other extensions.
In addition, your land might have restrictive covenants than require you to obtain permissions, but once again, these are mainly aimed at permanent alterations/extensions.
Also, if you are within a national park, areas of outstanding natural beauty, world heritage site or conservation areas, then planning permission almost certainly will be required.
For further details, you can visit the UK government Planning Portal or contact your local council.
How tall can it be?
The maximum height is determined by how close you are to the boundary (known as the curtilage) of your garden, and what type of roof you are going to have.
Will any part of it be closer than 2 metres from the curtilage?
Being close to your boundary means a greater potential visual impact for your neighbours and/ or to the character of the area, so if this is the case, then the maximum height permitted is 2.5 metres regardless of roof type.
Will it be more than 2 metres away from the curtilage?
If your building will be more than 2 metres away from the ‘curtilage’ of your house then a flat / slab roof can be up to 3 metres high and a maximum of 2.5 metres at the eaves. If you have dual pitched roof, then it can be up to 4 metres high, again with a maximum of 2.5 metres to the eaves.
How much floor space can it have?
In theory, it can occupy up to 50% of the space within your curtiladge. However, buildings above 15m2 might be subject to building regulations and/or require planning permission – it all depends on the intended use and to some degree, the materials used in the construction.
The floor space has to be on one level i.e. you cannot create an ‘upstairs’. Oh and the ‘use’ of the building has to be ‘ancillary’ to the house ie you can’t live in it!
What about Building Regulations? Well that’s a separate topic and we’ll be talking about them in another article, but for most garden buildings under 15m2, they won’t apply.