Underpinning needed for side extension - advice needed

[agentscully]

I’m hoping for some advice.

We’re looking to have a side return extension built but we’ve been told it will need to be underpinned. Has anyone any experience with this? Cost of work? Any insurance issues? Or, issues with selling on?

If it’s too expensive we’re thinking of taking down some internal walls but have been told these may have to be underpinned too. I’m just not sure how big of a deal this is.

Any advice gratefully received.

Underpinning is usually a word for beefing up existing foundations. Are you hoping to reuse parts of a previous structure. It's not clear.
Do you mean piled foundations?

@GrubzUp
Thanks for the reply. It will be a new structure so not sure if they mean the whole structure will need underpinning or if it’s just where the beams will be situated to give extra support to original building.