Ground floor extension plans
Professional plans for single-storey rear, side-return and wrap-around ground floor extensions. Most fall under permitted development — meaning no full planning application required. We'll tell you straight away whether yours qualifies.
The four common ground floor extension shapes
Ground floor extensions are the most common Arkiplan project — over 600 drawn — and they fall into four broad shapes. Which one you can have depends on your house type, your garden depth, and your local planning rules.
Extending out the back of your house, usually 3m–6m deep. Most common form of ground floor extension. Often permitted-development if depth limits and side-window rules are met. Usual finish: open-plan kitchen-diner with bifolds.
Filling in the alley alongside Victorian and Edwardian terraces — that wasted strip between your kitchen and the side wall. Adds 6–10m² of usable space. Frequently permitted-development.
Combines a rear and a side-return into one continuous L-shape. The biggest single uplift in ground floor liveable space without going up a storey. Usually needs full planning permission rather than PD.
Less common but worth knowing about. Porches under 3m² external footprint and below specific heights are usually permitted-development. Larger front extensions almost always need full planning permission.
What's included
Single-storey extensions are simpler than two-storey ones — but the council still wants the same standard set of drawings. Here's what arrives in your Arkiplan package.
See all packages →Planning rules for ground floor extensions
The good news: most ground floor extensions don't need planning permission. They fall under permitted development — but only if they meet a series of strict rules. Get any one of them wrong and the whole thing reverts to needing a full planning application.
For a single-storey rear extension on a detached house:
· Maximum depth: 8m (subject to neighbour consultation)
· Standard depth without consultation: 4m
· Maximum height: 4m at the ridge
· Eaves height within 2m of boundary: 3m max
· Materials: must be similar to the existing house
For a terraced or semi-detached house, the limits are tighter — depth maxes out at 6m (with consultation) or 3m without. Side-return extensions follow a different rule set entirely.
You'll need full planning permission if you're in a conservation area, your home is listed, you're on Article 4 land (where local councils have removed PD rights), or your design exceeds any of the above limits. We handle full planning applications too — including the awkward conservation-area ones.
Even when your project qualifies under permitted development, we strongly recommend applying for a Lawful Development Certificate. It's a paper trail that proves to your future buyer (and their solicitor) that the extension was legal. Without it, you'll have a hard time when you come to sell.
For a more detailed read, see our blog: Ground Floor Extension: The Complete Homeowner's Guide and Do I Need Planning Permission for an Extension?
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