Cost of single v double storey extension

[LovingTheSunshine]

Hi
I'm in Herts and we are contemplating an extension to create a new kitchen/diner/family room across the back of the house and a bedroom/ensuite above. I believe that it doesn't cost double to do a 2 storey extension - is this right? Is a lot of money in the foundations? Thanks

Currently adding a kitchen/breakfast room downstairs and a bedroom upstairs, plus a separate laundry/utility room. Reckon it's going to be at least £150k. Sigh!

Gulp!

Just to update you LovingTheSunshine we have now got the final written quotes in for our two storey side and one storey rear extension (rather than fag packet estimates from the builders...). Cheapest was £190,000 +VAT most expensive was £250,000+VAT plus kitchen plus architect's fees. The cheapest was £10,000 above the architect's worst case scenario highest estimate... There is a lot of refurb work included in that like new timber windows, re-wiring and patios and a drive...but still...... We are reeling from the shock. Oh and the architects's original estimate (when we were at the drawing stage) was £100,000.

Cripes ixos!!!!! That is huge money...what are you going to do? We have been looking at knocking through the kitchen to the dining room & seeing if that would work. We have a playroom off the dining room & double door off the dining room to an insulated conservatory/garden room at the back. The architect said we have lots of useable space, which I know we do, but the conservatory still won't get used a lot in summer even though it doesn't get as hot as it did pre insulation. But we could keep the door open from the dining room for at least 3 months of the year. Decisions, decisions....

Sorry, to clarify we are looking at options in using current space instead of adding an extention :)

we have a quotation for a demolish garage and build 2 double extension of 2.8m x 9.5m; an additional new pitch roof size of 1.7 x 8m. 9 windows. 1 bathroom, plumbing & electrical . all for 87000 + VAT. we are in avon south west.