The more traditional farm house had tended to be the house itself and then alongside a byre for the animals. With a Bastle house this changed. The animals lived on a ground floor and the people above.
Typically there would be no stairway to the first floor, just a trapdoor and a ladder which could be pulled up. The Walls and door would be very strong.
Housty Bastle house lies in the Allendale valley. Technically this is a little further south than would be expected but in reality the only restrictions on the range of Bastle houses was the area which was terrorised by the Border Reivers.
Housty itself has been dated back to 1625.
Other references
Housty Bastle house. More pictures.