Felin Isaf, including former Water Mill to rear

Felin Isaf is an early and later 19th century mill and mill house located on the River Alun. The mill building at the rear is likely from the early 19th century, while the mill house dates from the mid to later 19th century. This site has been recorded as a mill since 1326.

The mill house is a two-storey structure with three windows, built from rubble stone and previously roughcast. It features an imitation slate roof and roughcast end stacks. The windows are 20th century timber sashes, with a 9-pane design above and a 12-pane design below, all having cambered brick heads. The center window has replaced a ledged door, and all windows have been changed since 1981. The end walls are roughcast, and there is a lean-to on the eastern end.

The mill building behind is constructed from rubble stone and has a southern gable over the mill stream, although the former overshot water-wheel has been removed. There is one small fixed light at a low level and one 2-pane fixed light with a cambered brick head above. Evidence in the gable suggests that the eaves have been raised. The western side has been extended since 1981 with large French windows, although the original wall remains intact within. The eastern side features a lean-to to the left and a recessed porch with 20th century double doors.

The mill is supplied by a mill-leat from Cathedral Close and was known as the Bishop's Mill, also referred to as Dewiston, Dewston, or Lower Mill. The complete mill machinery is still present within the mill section, and there is a date inscribed as 'I Roberts 1810'.