The Plas was sold in 1947 and converted into flats, remaining in private ownership and closed to the public between until 1979.
The mansion was bought in 1979 by AJ Clarke who refurbished the building, converting it into residential flats. During the mid 1950’s, following Mr Clarke’s death the Plas was sold to the Macmaster family from Manchester, who used part of the building to store furniture.
By the 1970’s, the Plas was left empty and was falling into a state of disrepair with water pouring through the roof. In 1979 it was bought by the artist Gwyneth ap Tomos and her husband, Dafydd and they worked hard to renovate the mansion throughout the 1980’s and early 1990’s, saving it from dereliction.
This was a very important period in Plas Glyn-y-Weddw’s history, Dafydd and Gwyneth saved it from becoming a ruin and without their hard work it is likely that its doors would never have opened to the public again. During the 15 years Dafydd and Gwyneth ran the gallery many significant exhibitions were held by leading Welsh artists.
The Friends Organisation was formed by Gwyneth and Dafydd in 1987 to promote and support the gallery.