Will the house we build be an interior cell? At first I though it would be, but then I saw the transition from http://youtu.be/TvhQZoyZn1g?t=19s, we notice a front door being placed on an already built house. So this suggests to me that our house will not be an interior cell, but then what about the well known snow/rain bug? The one that allows snow and rain to pass through sheltered exterior locations.

Could they have fixed this bug? Or will our houses be interior cells?

I think it will be a different cell just like every other building or home in Skyrim. Wouldn't make sense to change it.

I don't imagine your house having anything in it until you finish it by putting a door on it.

I would venture that once the roof goes on, the door appears and the house becomes an interior cell.

The house is built in stages the video is basically skipping the DB returning to the crafting bench.

Yeah it doesn't become an interior cell until it's complete. You can see how you can walk around the 2nd story even though it isn't done, but has walls and a roof. You could fight enemies there if they attack it seems so it is a exterior cell.

But hey maybe they'll put invisible walls up and not let us tour are inprogress home...