Roath Park House was built in 1897 within the Pleasure Garden as the official residence for the Parks Superintendent (later Chief Parks Officer). It was home successively to William Pettigrew until 1915, his younger brother Andrew Alexander Pettigrew from 1915 to 1936, and William Nelmes senior, who was appointed Chief Officer of Parks and Open Spaces in September 1936. When Nelmes retired in 1967 his son, also William Nelmes, succeeded him as Director of Parks and moved into Roath Park House with his family.
One of the rooms in the house served as a departmental office until the new Parks Depot in Wedal Road was completed in 1901.
A telephone line was installed in 1901 by the National Telephone Company for an annual charge (including unlimited use) of £8. In April 1914 a tender was accepted to install electric lighting.
In July 1949 repairs and improvements to Roath Park House in the form of a new kitchen and bathroom were undertaken at a cost of £53.
There was a World War 2 Anderson shelter at the bottom of the back garden, near the tennis court, which still existed in the early 1970s.
The house ceased to be the official residence of the Director of Parks in 1975 when William Nelmes junior vacated the property. It was then used as accommodation for other members of the Parks Department. In February 1982 it was reported that the house had not been used for accommodation for employees since December 1981. The building suffered from serious dampness, had no adequate heating system, was slowly deteriorating and considerable finance would be necessary to bring it up to a condition in which it could be re-let. The Leisure and Amenities Committee agreed in principle that the building be converted to office accommodation as the district office for the northern area. In December the Committee approved works estimated to cost £42,000 to create office space with living accommodation on the first floor. Additional expenditure of approximately £22,600 was approved in July 1984 to remedy extensive dry and wet rot. The works were reported to be complete and the building ready to be occupied in September 1985.
Beginning in September 2019 Cardiff Council carried out a programme of renovation work at Roath Park House, which was expected to finish in January 2020.
Sources of Information