Do I Need Planning Permission? A Complete UK Guide for Homeowners

The Golden Rule: Permitted Development

Most common home improvements don't need planning permission thanks to "permitted development" (PD) rights. These are automatic rights that let you carry out certain building works within specific limits. If your project stays within the PD limits, you can build without applying to the council.

But there are important exceptions. Your PD rights may be restricted or removed entirely if your property is listed, in a conservation area, an AONB, a National Park, or if a previous planning condition or Article 4 direction has removed them. Always check before you start.

Single-Storey Rear Extensions

This is the most common home improvement. Under PD, you can extend at the rear without planning permission if you stay within these limits:

• Detached houses: up to 8m from the rear wall (was 4m, increased under prior approval scheme)
• Semi-detached and terraced: up to 6m from the rear wall (was 3m)
• Maximum height: 4m overall, 3m eaves height if within 2m of a boundary
• Must not cover more than 50% of the garden area
• Must use similar materials to the existing house

For extensions between the original 3m/4m limits and the new 6m/8m limits, you'll need to apply for "prior approval" — a simplified process where neighbours are notified and the council checks for impacts. This costs £120 and takes 42 days.

Loft Conversions

Loft conversions are PD if the additional roof space doesn't exceed 40m³ (terraced houses) or 50m³ (detached and semi-detached). Additional rules:

• No extension beyond the existing roof plane facing the highway (no front dormers)
• Must not extend above the existing roof ridge line
• Side-facing windows must be obscured glass and non-opening below 1.7m
• Materials must be similar in appearance to the existing house

Outbuildings (Sheds, Summerhouses, Workshops)

• Maximum height: 4m (dual-pitched roof), 3m (any other roof), 2.5m if within 2m of a boundary
• Must not be forward of the principal elevation
• Total area of outbuildings must not exceed 50% of the garden
• Must not be used as self-contained living accommodation

Fences, Walls and Gates

No planning permission needed if the fence or wall is 2m or under (1m if next to a public highway). However, listed buildings and conservation areas have stricter rules.

Driveways

If you're paving over your front garden, the surface must be permeable (porous block paving, gravel, etc.) or drain to a lawn or border. Impermeable surfaces over 5m² that drain onto the highway need planning permission. This rule was introduced in 2008 to reduce flood risk from rainwater runoff.

Solar Panels

Solar panels on roofs are generally PD. They must not protrude more than 200mm from the roof surface, must not be higher than the roof ridge, and must be removed when no longer needed. Wall-mounted panels need planning permission in conservation areas.

When You Always Need Permission

• Building a new separate dwelling (house, annexe with kitchen/bathroom)
• Major changes of use (home to business, agricultural to residential)
• Work on listed buildings (need listed building consent, separate from planning)
• Work that significantly affects the character of a conservation area
• Two-storey side extensions (almost always need permission)

The Lawful Development Certificate

Even if your project is PD, it's worth applying for a Lawful Development Certificate (LDC). This costs around £206 and gives you formal written confirmation from the council that your project doesn't need planning permission. Estate agents and solicitors love seeing this during property sales — it prevents delays and disputes.