At the heart of the two-unit house was the living room, variously called the house, the firehouse, the kitchen etc. and this contained the principal or only hearth or fireplace. Off this room opened a room serving as a parlour or ground floor bedroom. In the earlier and smaller examples this room was unheated; later a gable fireplace was included. A dairy, or similar ventilated storage space, was partitioned off the parlour or was included in a leanto extending behind the living room. Virtually all surviving examples of the two unit houses have an intermediate floor, the earlier and smaller buildings having an undivided loft in the roof space, the later and larger farmhouses having quite well-proportioned bedrooms upstairs.
A tight winding staircase ran either from the rear of the living room or, rather surprisingly, from out of the parlour. Most commonly, however, the staircase was contained in a deep projection from the rear wall. The main heat source was the open fire burning peat on a hearthstone in an inglenook. The focus of domestic life and the centre of folk practices and superstitions connected with the house, the inglenook dominated the traditional farmhouse interior until it was superseded by the coal-burning castiron range. The upper part of the inglenook was the hooded chimney consisting of a wide flue gathered together in a half pyramid to join the chimney stack.
The hooded chimney was made of studs lined with wattle, clay daub and plaster, and joined a stone chimney stack which was carried on wooden cantilevered beams. In later examples both chimney and stack were made of stone, retaining the original shape but modified to a graceful curve. At one side of the hearth was a stone or timber partition called the 'heck' and this shielded the inglenook from the worst of any draughts coming through an adjacent door. At the other side, the front wall of the house included a small window, the 'fire window', which lit the deep inglenook. The hearth wall usually included a recess which served as a salt or spice cupboard and other recesses or 'keeping holes' for a lamp or the farmer's pipes. Usually the spice cupboard had a carved door but many of these have been removed.
Occasionally houses of this plan were entered through a gable wall but in nearly all the examples now to be seen the main doorway is placed near the centre of the elevation and opens directly into the living room. Only in later centuries, it seems, was a single-storey porch added to help counter the draughts from the winds sweeping in from the fells. The basic plan of the two-unit house was employed until well into the eighteenth century. It met the minimum domestic demands of the small farming family for a more public room for eating and entertaining, a more private room for the master and mistress and for storage of seed corn and fleeces, and some loft space for the children. At the same time the room sizes and the room heights could be increased without altering the plan so that later and more progressive farmers could enjoy a familiar plan in improved form.
Like the two unit plan, the cross-passage and downhouse plan consisted of two main living rooms on the ground floor but in addition there was a substantial service room at one end. A cross-passage ran from the front to the back of the house alongside the wall which contained the principal or only hearth; access to the house was through a doorway in the hearth wall near the end of the cross-passage and by way of a short lobby formed by the heck partition.