Extending on existing extension

[Pronounciata]

I have no idea if this is something that's possible, but we are in a home that is great except size (unexpected pregnancy and need to care for a relative). We are ok at the moment but in the next couple of years we will need an extra two bedrooms.

In our area this will be a massive leap in property cost.
We can convert the study to a bedroom and create a garden office instead but we will still need a further bedroom.

It's a terrace with a rear extension which was pretty well done with lovely high ceilings (done before we arrived) and we have already done the loft.

I'm sure it's impossible but has anyone created a two story extension in a situation like ours or would this require brand new foundations and end up being very pricey?

I am trying to think of ways to be creative with the space we have but there's only so much you can do with the small bedrooms, I don't think chopping them around would work.

I'm going to have to move aren't I?

There are two issues here -

1. was the original rear extension built with sufficient foundations to support a second story? An structural engineer could report on this. It is possible that it was built with that in mind.
2. Have you extended to the maximum allowed by your LA for the type of house you have? Our LA allow for 40% of original floor plan for mid - terraces. Once you've reached that, you'd be hard pressed to get approval. You LA will have their rules on the website.

Would the garden office need planning? Some do - this may also be included in the maximum extension allowance.

Depending on the exact care circumstances, could you look at a granny annex, rather than a garden office? No good if close monitoring required, but might work if it's someone who is a bit more independent (and might help them keep some independence as well)

A study could be easier to make space for reconfiguring the house.