Cottesmore including attached E conservatory and NW wing.

Cottesmore is a grade II* country house comprising a main block with attached east conservatory and north-west wing. The building is rendered in stucco lined as ashlar, with a slate hipped roof of deep eaves and two rebuilt red brick ridge stacks.

The principal front is three storeys arranged in five bays. The windows are small-paned sashes with bands under the eaves and between the first and second floors. The upper floor has square six-pane sashes, while the first and ground floors have twelve-pane sashes. The ground floor is dominated by a full-length portico of eight Bath stone Roman Doric columns raised on a double step of cut Pennant stone, with paired columns to the centre bay. The columns support a Greek Doric painted wood entablature with triglyphs and metopes, very similar to the porch at nearby Sealyham. Small signs suggest the colonnade may be reused: there is a cut-out on the left column and some holes in the step possibly indicative of a former metal veranda, though nothing is conclusive. The centre doorway is wide, with a stone step and a six-panel fielded-panelled door with side-lights and top-lights, flanked by panelled piers with roundels at intersections—similar to the entrance at nearby Poyston.

The west side has four bays of similar character but without the portico. Numerous blank windows are present, including three to the attic (two with inserted twentieth-century windows) and one each to the right bay of the first and ground floors.

The east side comprises three bays with blank windows to the left on the upper two floors and ground floor. An attached conservatory extends eastward along this elevation, running for ten bays with renewed timber small-paned glazing between thin cast-iron pilasters. Below the glazing are panelled piers with rosettes. The conservatory has a glazed timber roof with short pitch on the north descending to a rubble stone rear north wall. A glazed east end comprises four bays. A six-panel door to the basement with overlight is present.

The rear north elevation is roughcast with three equal gables, the outer ones featuring red brick renewed chimneys. One attic twelve-pane sash is positioned to the left of the centre gable, with twelve-pane sashes on each floor between the left and centre gables. A door onto the service stair accesses steps in the angle to the rear north-west wing.

The rear north-west wing is two storeys with a hip to the north end. The east side has four bays: one blank and three nine-pane windows above, a blank window, a hipped lean-to, a door and a twelve-pane sash below. The west side has two nine-pane and one twelve-pane sash above, with three twelve-pane sashes below that are not aligned.

The entrance hall is positioned centrally with a staircase to the rear and two doors to the left, one to the right, giving access to principal rooms to the south-west, north-west and south-east. All doors are six-panel with panelled shutters. The staircase is a fine cantilevered stone construction with cast-iron balusters, lit by a top lantern over a circular light with coloured glass to a floral pattern.

The south-east room features an exceptionally large ceiling rose with lotus, anthemion and acanthus leaves, with an anthemion-pattern ceiling border. A white marble fireplace with rosettes is present. Sliding double half-glazed doors on the east wall open into the conservatory. The south-west room was formerly the library and contains a large fitted bookcase on the west wall of six bays with glazed doors and roundels to the piers between. The north-west room has a similar very large ceiling rose and neo-Grec ceiling border. A plain marble fireplace with a mid to later nineteenth-century cast iron grate is present. The walls of this room are boarded, lined with canvas and papered. An elliptical-arched recess is set into the north wall.

Within the conservatory, original cast-iron piers between renewed small-paned glazing are wider than the thin pilasters visible on the exterior, here displaying Corinthian capitals. The timber roof structure may be later nineteenth-century or early twentieth-century with one long pitch and a short rear pitch clad in corrugated plastic sheet. A liftable ridge, now removed, formerly existed but some of the mechanism survives. The floor is laid in stone flags.