Single vs double-storey extensions: which adds the most value?

The right extension depends on what your house needs, but the value question does have a real answer.

Single-storey extensions

Best for: opening up the ground floor. A rear or side-return single-storey extension gives you the kitchen-dining-family room every buyer looks for. In most Worcestershire family homes, a well-executed single-storey extension typically returns 10–15% of home value.

Double-storey extensions

Best for: adding bedrooms. If you can go from a three-bed to a four-bed (or four to five) with a two-storey rear extension, you're crossing a real market threshold — and the return typically sits at 15–20% of home value.

Bonus: per square metre, a two-storey extension is usually cheaper than a single-storey one, because one foundation and one roof serve two floors.

The real answer

The best-value extension is the one that fixes the biggest thing the house is missing — a fourth bedroom on a three-bed, or a proper kitchen-diner where there isn't one. Talk to us about your house and we'll tell you honestly which route makes more sense.