Rosehill House, associated outbuilding and boundary walls to north and east

Rosehill House is a Tudor and Jacobean revival-style house, possibly designed by E. B. Lamb around the 1840s, with late 19th-century alterations and a small early 20th-century extension. The house is constructed of red brick laid in Flemish bond, decorated with diapering of Staffordshire blue brick, with sandstone dressings, under gabled roofs clad with alternating courses of Staffordshire blue plain tiles and fish-scale tiles.

The house has two storeys plus attic and is situated on a corner plot fronting Wilfred Street to the west and Rose Hill Street to the north. It has an asymmetrical plan consisting of two parallel ranges running north-south, each with a central projection under gabled roofs. The west projection is the three-storey entrance porch and that to the east is a two-storey domestic projection housing the housekeeper's room on the ground floor. The service rooms were sited to the north leaving the main reception rooms facing south.

The west elevation was originally symmetrical and of three bays, the central one developed as a three-storey entrance tower under a shaped gable. The recessed entrance is set under a four-centred arch with outer two-leaf storm doors hung on bifurcating wrought-iron hinges. The inner door is six-panelled (the upper three are glazed), and has glazed side lights and a three-light overlight. One single-light casement window lights each floor above. The bays either side have a cross casement to the ground floor, a two-light casement to the first floor, and a saw-toothed brick cornice at eaves level. The roof terminates in plain gable coping to the north and south, and there is cast-iron ridge cresting which is common to all the 1840s build. At the north end of the roof is a triple-flued, diamond, internal, gable-end chimneystack. Abutting against the north gable end is a two-storey extension built around 1910 as the consulting room for Dr. Charles Potter in the ground floor and domestic accommodation above, lit through two altered two-light casements to each floor. The saw-toothed cornice and fish-scale roof tiles have been copied from the earlier build, as has the triple-flued diamond stack which rises out of the west slope of the north gable.

The two-storey gabled east projection has vertical blue brick diapering, sandstone dressings and one two-light casement to each floor facing east, the lower one elaborated as a cross casement. There are saw-toothed eaves cornices to the north and south returns, and a triple-flued stack emerges above the wall plane on the north side. The northern spur of this wing is of two storeys with one two-light casement to each floor facing east, and a corner window at the first-floor turning into the north face. In the angle between these two elements is a two-storey flat-roofed extension built around 1910 as the new kitchen immediately north of the housekeeper's room, of red brick laid in English bond. A stone, single-light casement window remains to the first floor of the north and east elevations, but the corresponding ground-floor windows have been changed to three-light steel Crittall casements in the 1920s.

The south elevation presents two gables of unequal size and height. The western gable end has a two-storey canted bay window added in the 1870s and lit through one- and two-light sandstone casements. Between the two floors and in the plain stone parapet are floriated terracotta tiles and the attic storey has a single-light stone casement. The eastern gable end has a single-storey bow window, also added in the 1870s, which is lit from a four-light stone cross casement beneath a plain brick parapet with stone coping. At first-floor level is a two-light stone casement and in the attic is a square wall sundial under a gableted hood. Between the two ranges is a clustered four-flued chimneystack.

The entrance hall from the west door has a 20th-century tiled floor, a ceiling of exposed timber joists and a four-centred arch over the inner entrance door. Two six-panelled oak doors within bolection-moulded doorcases open into the original service rooms (to the north) and the dining room (to the south), and there is a third similar doorway immediately east into the small sitting room, which was built as the housekeeper's room. The mahogany open-well staircase has alternating turned and twisted balusters rising from the closed strings to the moulded handrails. Square panelled newels each have terminating obelisk finials and the soffits of the flights are panelled. A wall-mounted dado rail mirrors the rise of the handrail.

The small sitting room has two chamfered bridging beams running east-west and there are eight sprung service bells mounted on the west wall, tall roll-moulded skirting and a 1960s chimneypiece. The main sitting room to the south has a six-panelled entrance door of the same pattern as the others, and there is a wide four-centred timber arch in front of the southern bow window. A 1950s tiled chimneypiece is set in the west wall and two chamfered bridging beams run east-west rest on corbels. The ceiling is finished with a hollow and roll-moulded cornice. The dining room has three chamfered bridging beams, tall moulded skirting and the same shelf-picture rail as the sitting room and the hall. The service end of the ground floor and the around 1910 kitchen have less elaborate features and four-panelled doors with plain surrounds.

The first floor has a large landing from which four bedrooms open, each with similar six-panelled doors to those on the ground floor. The rooms repeat the motif of having one or two chamfered bridging beams in the ceiling. One room was converted to a bathroom in the mid-1970s. The attic floor has a staircase landing with turned balusters and there are plain six-panelled doors in simple frames to each room.

To the north-east of the house is a single-storey gabled outbuilding of the 1840s clad with plain tiles and with Staffordshire blue brick diapering to the north and south elevations. The roof is over a brick saw-toothed eaves cornice and there are sandstone gabled copings. This is attached to the house by a brick wall and railings which form a boundary around the north and west sides of the house.

Rosehill House appears on a map of 1852 and was probably built in the 1840s. At that time the house was surrounded by horticultural fields and was situated opposite the new Arboretum which had been established in 1839-40. The entrance lodges for the Arboretum were built for J. C. Loudon (1783-1843) by Edward Buckton Lamb (baptised 1805, died 1869), a nationally important architect, whose imaginative neo-Gothic and Tudor revival designs are stylistically similar to Rosehill House. There is no direct evidence for Lamb's involvement in the design of Rosehill House however. During this period the population of Derby was greatly increasing and new suburban districts, such as Rose Hill, were being developed. By the 1860s the first terraces had been constructed along the south side of what was now officially called Rose Hill Street. Around this time Rosehill House was bought by William Sale, a prominent manufacturer and proprietor of Sale & Co, silk throwsters. On his death in 1875 the house passed to his son, who sold it in 1891 to the Rev. Claude H. Parez, the Chief Inspector of Schools for Derby. The sale allowed the development of Wilfred Road across part of the garden to the west of the house, which left the building occupying the corner of two streets. In the early 20th century Rosehill House was occupied by Dr. Charles Edward Potter who used the former kitchen as a waiting room.

The house has been altered since it was first built, with the addition of the canted bay and bow windows to the south elevation in the later 19th century. In the early 20th century the former kitchen was extended from the north-west corner of the house up to Rose Hill Street to provide a consulting room for Dr Potter; and at the same time a new kitchen was added to the east side. The 19th-century conservatory, located in the south-east corner, has recently been removed.