Per sq metre, you can expect to pay in the region of £1000. This means, average prices for a 3m x 3m garden room extension will cost upwards of £9000. Costs vary depending on the materials used, additional trimmings and of course your own post handover ideas also. Compare this to a side extension on a UK semi-detached home, where all you really needed was one extra room, and you are comparing £9-15,000 vs £50,000 + and the longer build time.
So if costs per square metre are the same between extensions and garden rooms, why such a big difference for a finished project?
Well it comes down to ‘dead space’. A side extension requires connecting structurally to the main residence as well as space over and above that additional room you wanted. Just as two homes of equal square footage can feel vastly different in how much livable space one has over another – the final bill for a garden room extension will always come in far cheaper. That’s why they are being built in ever increasing numbers.