yup check with engineer - get architect to draw it -0 do you have the inital house plans - nope then you need to do it can help along the way - kosmosnooit - gave you decent advise - not sure on the architects he has used - mine were great - going up on another level can be tricky and allot harder than digging trenches - also gonna create more mess and stress on the home front - move out for a month or 2 if you can