I have an 8 X 12 wellhouse that I would like to add an 12 X 16 addition to.  The well house is built on a slab with a barn type roof.  My new addition will be a simple gable roof, and will be higher than the well house roof but the floors will be level. 

My question is, what problems do I have to watch out for, if any, by attaching my new slab building to the old slab building re; frost heave or settling, etc.  I want to have them attached to bring water and electricity into the new addition without having to bury these lines.

Thanks in advance for any help.