The Sunday School at Llidiardau is a small mid-nineteenth century single-storey stone building with a slate roof and a red brick gable stack at the western end. It is built in the Vernacular style of the gable entry type. In both the northern and southern long walls there are two flat-headed nineteenth century window openings with slate cills and iron-paned lattice windows. There is a late twentieth century lean-to against the eastern gable, enclosing a stopped and chamfered doorway with a wooden-boarded door. Inside are two nineteenth benches and a fireplace at the western end. By 2003 this chapel stood disused.

RCAHMW, May 2011