That was what happened with the farmhouse my mom grew up in. My great-grandparents built it as a two-story - kitchen, dining room, living room on the main floor, 2 bedrooms and a bathroom upstairs. When my grandparents moved in, they added the single-story addition - master bedroom, 2nd bathroom, and a study (which doubled as my uncle’s bedroom when he was a boy).
“Clapboard farmhouse”, perhaps? To us it was just “the farm”. 
I’d call them clapboard houses but I don’t know if that is a style or a type of construction.
Here’s a little trivia regarding these add-on farm houses: The young couple would start small and as their families and fortunes grew they could afford to add on. Frequently on the farmplace there will be another, smaller and newer, house which Grandpa and Grandma will move into when the eldest son takes over the farm. Which is becoming increasingly rare.
I appreciated the comment about the kitchen being included in the two-story portion and helping to heat the house. The early settlers did quite a bit of outdoor cooking during the summertime.
And from the movies: the Ed Gein House in WI was constructed in this manner and served as the model for the Texas chainsaw massacre house in the original eponymous film.
The "I-House"was a standard around the country in the 19th century. It was very simple- usually2 over 2 with a center hall (sometimes just a staircase in one room) and it was the plain black dress of vernacular architecture. One reason it was so popular was that it was very easy to add on to when the family got larger or richer- just tack on a wing- and in doing this sometimes the front became the back or the side.
I think that’s what this is- an I-house that a wing was added to and the wing became the entry room.
Also, while the term Greek Revival conjures images of southern mansions with huge columns, that was only one form and obviously only for the rich. Most Greek revival homes were much plainer- example example example. The style was defined by the pitch of the roof and the relatively straight lines et al. Some I-houses were also Greek Revival.
I think Sampiro describes better what I was getting at. And I can’t find any reference to that book at all. It was laying around at a newspaper where I used to work and I used to spend hours poring over it and musing about times past. When I wasn’t out raking muck, of course.
In a book called A Field Guide to American Houses by Virginia and Lee McAlester, that style is called a gable front and wing. The two-story main section has a gable at the front and the one or sometimes two-story addition wing is set at right angles.
Googling dubs’ information finds a design labeled gable front and wing which looks a lot like the OP’s designs.
I was going to say saltbox but that’s not it, either. And since I live in the area the OP’s pictures are from and see that style all the time, you’d think I’d know. But I don’t.
Hmmmm…this looks close.
Oh, great…the link went to the homepage. let me see if I can fix it in the five minute window!
ok, click on home portfolios, regional collections, the Green Horizons, NC link…fourth house in the gallery…second row left.
