House Extensions in Darwen & Lancashire

Many extensions can be built under Permitted Development rights, but this depends on your property, its planning history and local restrictions. We'll help you understand what applies to your home before design work begins.

The right configuration, rear, side, wraparound or double-storey, depends on your garden, existing layout and what you're trying to achieve. Our extension explorer is a starting point; a site visit confirms what's realistic.

Timelines vary with scope, so we don't quote a fixed figure until a project has been properly planned. What we can say is that most delay in building projects comes from poor preparation and uncoordinated trades, which is exactly what our process is designed to remove.

Most extension projects allow you to stay in your home, though there will be periods of disruption, particularly around structural work. We'll talk through what to expect for your specific project.

It depends heavily on size and specification. Published UK ranges put a single-storey extension at roughly £1,800-£3,000 per m² (see our house extension cost guide for sources), which puts a very small, simple extension within reach of that budget but a typical 20-30m² kitchen-diner extension well above it. A garage conversion or a smaller garden room often fits a tighter budget better than a new-footprint extension does.

It's one of the more reliable ways to add usable space and value, though the actual uplift depends on your local market, the quality of the work and how the finished space compares to similar homes nearby. We won't quote a specific percentage figure, since that varies by property and area rather than being a fixed rule.

A rear extension projects into the back garden. A side extension fills the gap between the house and the boundary. A wraparound combines both into one L-shaped space, and is typically the largest single-storey footprint available. Each has its own permitted development limits, which our extension explorer and permitted development checker cover in detail.

If the work is on or near a shared wall or boundary with a neighbouring property, the Party Wall etc. Act 1996 is likely to apply, and a wraparound extension in particular can engage it on two boundaries rather than one. We'll flag this early if it's relevant to your project.

Almost certainly, and they're separate questions. Planning permission (or Permitted Development) covers whether you're allowed to build something; Building Regulations cover whether it's built safely and to current standards - structure, insulation, fire safety, ventilation. Most extensions need Building Regulations sign-off regardless of the planning route.