Some have tried to distinguish vernacular houses on the basis of the position of their hearth. The hearth can be on a gable or in a central position. However this apparently straightforward classification is made difficult when additional rooms are added beyond a gable, making a gable hearth into a central hearth. A more useful method of classifying vernacular houses lies in the relationship between the door and the hearth.

Hearth Lobby houses

In this type of house a wall, called the jamb wall, of brick or wood is positioned between the front door and the fireplace. It was usual to have a small hole or window in the jamb wall to allow light into the hearth and to allow those inside to see the door. Often there was also a small window in the rear wall providing further light to the hearth area. Work by the geographers Des McCourt and Estyn Evans suggests that this house type is not indigenous to Ireland but was introduced from England in the early seventeenth century. Hearth lobby houses are not found, except for occasional outliers, in North Antrim, County Derry, West Tyrone or East Down. There are no examples recorded in County Donegal. The nearest to Inishowen are outliers in Co. Derry, close to Limavady.

Direct-entry houses.

Some houses in Ireland were constructed with a front door opening into the room with the fireplace. The earliest houses of this type that remain are byre-dwellings where people and animals were housed together. Milking cows needed to be kept indoors in Winter and during the night in other seasons other than Summer. Byre-dwellings had doors opposite to each linked by a flagstone floor. The animals were tethered to the wall opposite the fireplace and a drain led downhill from that area to the outside. Evidence for these byre-dwellings in recent times in Ireland shows them to have been distributed throughout Ulster, including the Inishowen peninsula, and in the west of Ireland. Gailey, in Rural houses of the North of Ireland (1984) notes "The byre-dwelling was used widely in Donegal in the early nineteenth century. In 1814 it was seen as far east as Culdaff in Inishowen." Standing remains of byre-dwellings are confined to Counties Mayo and the western fringes of Donegal. Caoimhin O'Danachair mapped examples in north west Inishowen in 1970.

A number of alternative forms seems to have derived from byre-dwellings. In some cases the byre was separated from the main living area with a solid wall with separate access for the animals. Often this allowed the room where the byre would have been to become a bedroom. If a bedroom already existed beyond the fireplace, the 'new' room may have become a formal parlour. These would have been three unit houses, and occasionally four unit houses would also have been constructed.

By the mid-nineteenth Century it became more common to have fireplaces in other units to heat them. In two unit houses this led to a chimney being built in each gable. Three units meant that a chimney would be built between the two gable chimneys, in a asymmetric position.

Outshots

In many areas in the north and west of Ireland, the bed outshot is a feature of vernacular architecture, as here in a modernised cottage close to Malin Head.

This extension, usually to the rear of the dwelling, housed a bed next to the kitchen hearth. Traditionally this bed was used by the oldest inhabitants of the house. A shallow bed outshot meant that much of the bed protruded into the kitchen floor area but many outshots were deep enough to accommodate the bed entirely. The bed was screened by curtains or, more commonly in Donegal, by wooden doors.

Since the bed outshot is found in direct entry houses which have derived from byre dwellings, it is unclear why they are not generally found in of County Antrim and Down, for example. Perhaps they existed in the past but there is little evidence to support this. They date back at least to the early 19th Century and are a traditional element of vernacular buildings. Since they co-existed with houses without outshots, and in many areas were in the minority, they are not thought to provide the basis for a separate oushe type.