Two story extension costs

[123NorthWest]

I am thinking of buying a house that would need a two story extension. We are trying to figure out how much these cost now! Please could I ask if anyone has had a two story extension recently and how much you’ve paid per m2 for the basic water tight shell (windows, roof etc but not kitchens etc)
thank you

I know people who are getting quotes of £100k for single storey. It’s crazy money. I wouldn’t buy a house knowing I was going to extend. It’s cheaper to buy a bigger house to start with.

Where are you based?

Ask local architects, I think we were quoted £1500 per square metre.

We just finished a single storey. It was £2.5k per square meter plus VAT. Cost 80k in total with us doing the decorating. We had a quote four years ago that was literally half the price. Inflation isn't fun. We are in Wales.

Where in the country are you?

I don’t know the psqm amount but our recent 2 storey side extension was upwards of £100k building costs.

Friend in expensive part of country £200k all fitted out for bedroom and small sitting room, en-suite and downstairs loo.

Yup, start with about 3k per sqm for double storey.

Our single storey of about 5m x 6m quotes are coming in over 100k. Madness.

1930 small 3 bed semi (in London). Quotes to knock and replace garage with two story extension plus wrap around (3x6m) rear extension ranged from 150k-260 (excluding kitchen, finishing etc). First quoted 6 years ago at 80k.

We’re in the process of buying a house that needs a two-storey extension and have been researching current costs. For a basic watertight shell foundations, walls, roof, and windows, but excluding internal finishes,we were quoted last month in the range from £1,200 to £1,700 per square metre. This estimate can vary based on location, design complexity, and material choices.

If you're interested, this guide on the costs of a double storey extension was super helpful to us.