The current appearance of Somerled House dates from 1902 when additions, designed by William Turnbull, were made to an existing house owned by well-known businessman and politician Thomas Kennedy MacDonald (1847–1914) and his wife. MacDonald purchased the house from Frances Pharazyn in 1892. Other former owners of the property include Alfred Domett, former premier of New Zealand and a poet (owner from 1868 to 1874) and John Blackett, Engineer-in-Chief of the Public Works Department (1874 to 1889). It was MacDonald who gave the house its name of Somerled – a 12th century Scottish King of Argyll. MacDonald owned the house until 1900 when it was conveyed to his wife, Frances Rossiter MacDonald. The 1902 additions were designed by William Turnbull of Thomas Turnbull and Son and built by a Mr Humphries. William Turnbull later designed the grander Antrim House (Register No. 208, Category 1) (1905), and both houses include a distinctive turret.

T K MacDonald had many business and political interests. As well as an auction business, he was chairman of the Wellington Harbour Board, a Member of Parliament and Legislative councillor. His daughter Vera had her wedding reception at Somerled in 1907. Somerled’s household furnishings were advertised for sale in 1911 and in 1912 ‘superior board and residence’ at Somerled was advertised. T K MacDonald died in 1914 and his wife sold the house in 1920, after which it had a succession of owners. Files at Wellington City Council Archives include one from March 1932 relating to ‘reinstate dwelling damaged by fire’; repiling (1976); and additions and alterations (2006).

Somerled House is an Edwardian addition to a smaller Victorian residence. The construction is timber, with rusticated weatherboards, a corrugated iron roof, and kauri window joinery. The facade has projecting bays, porch, balconies and a square turret that give it a distinctive appearance in the streetscape. According to the Wellington City Council Heritage Inventory, the present entrance porch was originally a conservatory, and the most distinctive element on the facade is the square turret, ‘with its elongated windows, string courses, half-timbered frieze and hipped roof capped by iron fretwork’.

Although the building has been converted to apartments, the Wellington City Council Heritage Inventory notes that some of the original elements remain, especially on the first floor of the house: ‘One of the main features is a domed ceiling with a stained-glass lantern illuminating the central hall. A fine kauri staircase survives, along with kauri doors, arches, fire surrounds, and other features.’

Somerled House, with its distinctive porch, balcony and turret, is an important part of The Terrace streetscape, and one of a diminishing number of substantial wooden houses that once lined both sides of The Terrace that were built for middle-class Victorian and Edwardian Wellington residents. This building has been associated with a number of historically important owners. It is enhanced by a setting of trees and cast iron fence and gates.