Outbuildings: permitted development and build options

Permitted development limits

Outbuildings must be for purposes incidental to the house, not separate living accommodation. They must not sit forward of the front of the house, and height limits apply, with lower limits close to boundaries. They must not cover more than half the garden once other extensions are counted.

Listed buildings, conservation areas and some designated land have tighter rules. When in doubt, a Lawful Development Certificate gives certainty.

• Incidental use only
• Not forward of the principal elevation
• Lower height limit near boundaries
• No more than half the garden covered

Building regulations

Small detached outbuildings with no sleeping accommodation are often exempt from building regulations, depending on size, materials and distance from the boundary. Anything larger, or anyone sleeping in it, brings regulations in. Electrical work must still meet the relevant standards.

Bases and foundations

The base decides how long the building lasts. Options include a concrete slab, concrete pads with a timber frame floor, or ground screws. Whichever is used, the timber must be kept off the ground and away from standing water, with good ventilation beneath.

Timber frame and cladding

A studwork frame with a breathable membrane and timber cladding is the most common construction. Choice of cladding affects look and maintenance. Insulation in walls, floor and roof, plus a vapour control layer inside, turns a shed into a room you can use in winter.

Roofs, doors and windows

Flat roofs suit low heights near boundaries; pitched roofs give more headroom where limits allow. Good doors and double glazed windows make the building secure and comfortable. Guttering should discharge somewhere sensible rather than onto a neighbour's land.

Power, lighting and heating

An armoured cable from the house supplies sockets, lighting and a small heater. Plan socket positions around the use, whether a workbench, gym kit or storage. Data can be run alongside for use as a hobby room or study.

Security and insurance

A workshop or store full of tools is a target. Fit good locks, consider lighting on the approach and keep valuable kit out of sight of windows. Check with your insurer whether the building and its contents are covered, and whether they have any requirements for locks or construction. Tell them if the building will house expensive equipment. A simple alarm sensor linked to the house system is another inexpensive layer of protection worth considering at build stage, while cables are easy to run.

Choosing a position in the garden

Think about sun, views from the house, access for materials, and drainage. A building tucked into a corner may suit permitted development height limits near boundaries, but consider how far power needs to run and whether the path to it will be usable in winter. Keep clear of tree roots where possible, both to protect the tree and to avoid disturbing the base.

Rainwater from the roof needs to go somewhere: a water butt, a soakaway or a drain. Ignoring it leads to boggy ground around the base.

Maintenance

Timber cladding and frames last well when kept ventilated and dry. Check gutters, clear leaves from flat roofs, re-treat cladding when needed, and keep soil and plants away from the bottom of the walls. A few minutes each season adds years to the building.

How we build outbuildings

As carpenters and builders, timber frame outbuildings play to our strengths, and fitted benching, shelving and storage can be made in our own workshop. With over 40 years of experience, we start with a free site visit and provide a fixed-price written quote.

Common questions