Idea of cost for double storey extension!

[RoseGoldEagle]

We’re planning a 24 metre sq. double storey extension (8 by 3 metres) and am trying to get an idea of costs to know if it’s possible for us to afford it. My calculation so far…

£2000/metre sq for ground floor: £48,000
50% of that for first floor £24,000
=£72,000

The ground floor will be one big room (will need to add new kitchen which have budgeted for separately) but the upstairs will be a new bedroom with en-suite, plus an ensuite for an existing bedroom. Do I need to add more on for the upstairs- given it’s not ‘one space’ (I don’t mean to actually kit out the en-suites, am just meaning the actual building costs)

If anyone has any rough ideas how much extra I should budget for that, or if the above seems realistic, I’d be very grateful!! Thanks.

@TizerorFizz my builder was not VAT registered, his Dad was a financial adviser. As long as he didn't hit the tax threshold of £85k in turnover he could stay unregistered. The way he did it was ordered the supplies for the builder's merchant, passed the phone over to me and I paid them directly. Same with all the subcontractors like plasterer or electrician. I paid them directly. At the end of every week the builder invoiced me with a receipt for the work he had done and I transferred his wage into his bank account. The original quote was bang on, I just didn't pay it all through the builder. No tax dodge, just playing it smart. He liked his holidays so took breaks between each job. It also meant my costs were kept down as no VAT mark up.

We completed ours in 2021 in the SE. 2 storey side extension to kitchen downstairs and new bedroom upstairs measuring 3.5x 8. Quite high spec - aluminium glazing and vaulted ceilings. The basic building cost was £120k incl £35k of windows. All in it was nearer £200k including kitchen, flooring and finishes. I think it would be at least another 50% now.

£150,000 cash in hand as mentioned earlier isn’t under £85,000 pa for Vat registration. Any builder not turning over £85,000 is doing odd jobs. He obviously took long holidays.

Very surprised at these prices. Just paid £60 for double storey extension and porch. Bathroom will be extra. We didn't go over budget either.

To clarify do you mean 3x4 on 2 stories so 24 sq/m in total or 48 sq/m in total? My estimate of 120k is based on 24 sq/m and no other work.

3 by 8 on both storeys, so 48 sq m total

Easymeasy thanks, do you mind if I ask whereabouts in the country? We’re North East.