Ballpark extension costs (beyond online calculators/rules of thumb)

ilikecookies

Hello,

I have a question about getting an accurate-ish cost estimate for an extension.

I am aware of the general rules of thumb in terms of cost per sq/ft, that there are online calculators, etc.

However in this case the extension isn't straightforward as some alterations would be needed to the roofline as it is a case of potentially building on top of a single storey and merging into the existing second storey.

As such I'm not sure of the feasibility vs. the potential cost to muck about with the roof. Is there a half-way house between just getting a builder out to give a finger in the air cost and instructing an architect to do full plans? For example, would a chartered surveyor be able to give a ballpark cost from a one-hour site visit for example?

Thanks in advance for any help folks can give!

marksoton

Get quotes from local builders. We can't know your market..

martindow

You will need to dig out to see what foundations the existing building has. If these are inadequate for a second storey, you might as well price it as demolishing and building the whole thing from scratch. Many older buildings will have footings that are considered inadequate for what's there at present let alone cope with a second storey.