Doing ground and first floor extensions separately - how much extra?

[littlebylittle]

We have planning permission for ground floor extension and part of first floor. We can't afford the whole amount at the moment and I wondered how
much difference it would make to overall cost to do the ground floor bit now and first floor later. Whole cost likely to be 70k but that was architect estimate not builder's quote. Any ideas?

Ask a few builders to quote you for both situations.

I want to add bedroom on ground floor with shower room at side of the house Lally