Yes, it is a flat roof (in MN) and is a concrete and wood frame house.

Yes it is a flat roof. It is not possible to determine the deck type based on this photo. There are several possible options for a deck including a regular plywood, steel and concrete to name a few. I would assume it would be steel or concrete due to where the home is located. Snow is always a huge factor and can add a great deal of weight which will require a strong deck. Hope that helps

The flat roof deck is made up of truss joist wood 'i' joists (TJI) and plywood decking. It has a rubber membrane roof with tapered insulation to create positive drainage toward water drainage locations. The roof was engineered to account for snow loads.

The upper level of the house and all interior walls are wood framed - the lower level foundation walls are Thermal-Mass Concrete (two layers of exposed concrete with a layer of rigid insulation between them). There is little to no structural steel used in the construction of the house.