Foundations garage dormer bungalow

[101010]

Hi all.
We are buying a dormer bungalow which has an attached garage (flat roof) which the current owners have converted to a playroom. We are wanting to go above for another bedroom. I doubt the foundations are deep enough for standard second storey but as it’s a dormer bungalow only we would be putting a pitch roof on and the bedroom within.
Anyone know the rules regarding foundations and if we would need the full ‘normal’ double storey foundations or might we be okay ?

 

[^woody^]

The foundations for a garage are normally as deep as those for a house, but not as wide.

 

[frutbunn]

Generally on modernish housing estates the JCB drivers rarely changes the bucket just for the attached garage foundations, certainly none of the big house builders I've dealt with do, older sites they generally did change the bucket.
Either way the foundations will need to be assessed, some local authorities will view a trial hole prior to an app and fee is paid, but not all.
Unless the garage was a later addition the depth should be similar to the house.