Tilbygg

I am considering purchasing a property with a 2012 extension to the underetasje and 1st etasje. i want to build on top of this extension, creating an extension to the 2nd etasje. i need to know (as quickly as possible) if this can be done without significantly raising the height of the roof, as this would not be allowed. The extension only needs to accommodate one bedroom (and possibly a small bathroom) so does not have to be huge. i am happy to pay for advice/consultation/drawings but am very time limited is currently in the midst of a bidding round. i have included a cross section of the extension in its current form below along with an image, floor plans and a link to the property on Finn.