Callowell House, including outbuilding to the north

Callowell House is an early 19th century dwelling with later additions. It is constructed of hammerdressed, coursed rubble stone with ashlar dressings and stone cills, and has pitched roofs covered in concrete tile, along with three ashlar chimneystacks. The interior includes stone flags to the cellar. Window frames are a mix of uPVC and aluminium.

The house is arranged as a three-bay, single-depth building of three storeys, with a partial basement and a later 19th-century wing forming an L-plan (extended further in the mid-20th century). A further two-storey addition was built in the late 19th century to the rear, central and south bay of the house.

The symmetrical three-bay east-facing façade has two steps leading to the central door, and features ashlar quoins and architraves around the openings. The attic floor openings are smaller than those below. The north flank includes a ground-floor opening in the later 19th-century wing, stone cellar steps, and a rendered mid-20th century concrete extension with openings to both floors. The rear of the house has two flights of concrete stairs leading to a 20th-century single-storey extension with a pair of first-floor doors. A casement opening and an opening with a stone mullion are located above in the late 19th century wing. A late 19th century lean-to has a door to the left and irregular window openings. The south end of the house features an attached timber glasshouse/conservatory with glazing above low stone walls.

The internal layout was reordered in the mid-20th century, replacing the original staircase with a new lateral staircase to the rear. Some historic fittings remain, including panelled doors, a glazed door to the conservatory, other joinery such as glazed fitted cupboards on the ground floor, and a timber fireplace in one bedroom. The roof structure comprises sawn timbers secured with iron bolts. The original stone staircase from the cellar has been enclosed in concrete, and the ledged plank cellar door has iron strap hinges.

To the north of the house, attached to a drystone wall, is a rubble stone outbuilding with a monopitch roof. This outbuilding sits on the edge of a retaining wall that extends forward in front of the main house.