Trewarthenick

Trewarthenick is a country house, originally larger, dating back to 1686, with a datestone indicating that year. The house was altered considerably, including remodelling by H Repton circa 1792, and extended with flanking wings by Henry Harrison of London in 1831. These flanking wings were removed circa 1950. The front of the house is constructed of dressed and finely coursed slatestone, while other areas feature rubble stone or face-brick. It has Delabole dry slate roofs with gable ends to the rear wings. A 20th-century roof to the main part is concealed by a parapet over a moulded cornice. The house follows a double-depth plan with a nearly central stairwell and rear wings. It is two stories with a partial basement, and three-story wings.

The symmetrical east front has seven windows, with the three central bays projecting slightly under a plain pediment. The central doorway has glazed double doors and a fanlight over. Later stonework beside the door and above incorporates a datestone. The windows are 12-paned wood sashes, likely dating to 1831. Windows in the projecting bays, which lack horns, may have been added during Repton's remodelling. Original flat arches are above the openings. A sill band runs along the first floor. A moulded cornice and plain ashlar parapet may also be from Repton’s time. High stucco chimneys are likely the work of Harrison.

The north front features a Tuscan distyle in antis pedimented principal entrance, broken forward, with a tripartite sash above and a datestone dated 1934. Basement lighting to the left consists of two two-light granite mullioned windows, likely reused from an earlier house. High stone walls to the right enclose a courtyard and mask part of the rear, with an arched granite doorway. 18th-century lead downpipes are found on the left and right sides. The south face of the rear wing has 16-pane wood sashes.

The interior retains several original panelled rooms; an oak-panelled room in the south-east corner and a pine-panelled room in the north-east corner have robust bolection mouldings. A main room between the hall has a marble chimneypiece in a mid-18th-century style. Ceiling cornices are found in various rooms across different periods. A lantern lights the stairwell. Trewarthenick was the residence of the Gregor family from 1640. A watercolour of the house dated 1792 shows its original appearance. Repton’s Red Book for the property survives in the County Record Office. Rubble stone terrace walls with ashlar capping lie before the east front. A notable member of the Gregor family, William Gregor, discovered Manaccanite circa 1790, later renamed Titanium after German analyst J C Claproth, who also isolated the metal in 1794.