Ty-Du-Isaf comprises two houses: a 16th or 17th century house, which has been largely rebuilt; and an 18th century additional house to the south - dated 1788, and inscribed with the intitials, 'R H V'.
Source: Caernarvonshire Parish Files (CPF/L/26/02).
L. Moore, RCAHMW, 9th December 2011