Felin Crewi is said to have been built as a fulling mill in the late sixteenth-century, and to have been enlarged and converted to a corn mill in 1740. But the present three-storey building may be later. In the nineteenth century it is reputed to have had a wooden waterwheel 2.9m in diameter, replaced c1900 by an iron wheel of 3.8m diameter. Milling ceased in 1940 and the machinery was dismantled; but in 1985 extensive restoration took place, using machinery (including a 4.7m diameter wheel) from Felin Ffridd 2.8km to the north-west in Gwynedd (NPRN 40974). The mill was fully operational for some years, open to the public and with the adjacent former kiln converted to a cafe.

The mill is constructed on roughly-course rubblestone, with long slab quoins and a partial string course over the main door, under a pitched slate roof. The mill house forms a wing extending to the north-west, and attached to the south-west is a narrow, three-storey building of whitewashed rubblestone, formerly stables with accommodation over. Attached to this is a single-storey building, formerly a drying kiln.

In 1999 the mill and the adjacent buildings were converted to self-catering accommodation, retaining the machinery. The pitwheel, wallower and great spur wheel are behind a glass window, viewed from a kitchen, and an uncased pair of iron-banded millstones and the upright shaft with its crown gear are retained in an upstairs sitting room.

Information from Cadw Listed Buildings database and vendor's websites.
W J Crompton, RCAHMW, 1 October 2014.