Pentre Ffynnon Mill

Flagstone floors to ground level, wooden floors above with trapdoors. The R ground floor bay has wooden hoppers with chutes attached to the ceiling, along with belt drives. Wooden boarding around wheel and machinery to centre of S side; drive shaft with wooden pulley wheels for belt drives. Straight timber staircase against N wall. The L bay is open with 2 doorways leading into the adjoining single-storey range. On the 1st floor are 2 bed stones in situ, between which is an iron shaft with crown wheel driving shafts for pulleys and wooden wheels for belt drives. Roof structure of closely-spaced timber trusses in attic.

Large 4-bay mill of 2 storeys and an attic constructed of rubble sandstone with large quoins under a shallow hipped slate-covered roof. The 2-storey open-fronted porch to the N is under a corrugated roof and contains 3 wagon bays divided by rectangular stone piers. The sides are also open, with a single-storey U-shaped range, now altered, adjoining to the E. Wood planked bins to upper storey of porch (accessed from 1st floor, internally). Above the porch are 4 square ventilation openings with wooden slats to the attic. Inside the porch are doorways to L and R, both with planked doors. That to the L has a flat chamfered stone head, pierced with holes, probably reused from elsewhere. That to the R is wide with a Tudor-arched brick head. The doorframe has an inscription 'I W 1823'. To its L is a 2-light window opening, partly missing, and possibly inserted into a doorway. Further L is a doorway blocked with stone under a flat stone lintel.

To the S side is a large opening to the L (probably originally a wagon bay), now blocked in stone and under a segmental head of stone voussoirs. To its R at 1st floor level are 3 x 2-light iron-framed windows, most of the glazing missing, in chamfered stone surrounds with flat heads. To the attic are 4 square ventilation openings in stone surrounds, the wooden slats retained to the far R only. To the lower storey are 2 iron-framed windows to the R, aligned with those above. The L one is blocked with stone and brick. Small square opening to centre, now altered, with stone and brick lintel, which lights the machinery. At ground level is a wide segmental arched opening, in front of which is the wheel pit, now covered with a steel grille. The headrace runs into it from the S. An arc of the cast iron and wooden wheel survives in situ; it was probably high breast-shot and is at right angles to the S wall of the building. A wallower and wooden main shaft also survive and appear to be well preserved.

The W end of the mill has 2 square ventilation openings with wooden slats to the attic. Loading door offset to R to 1st floor with stable doors under a segmental head of stone voussoirs. Similar ventilation openings to E end; opening to 1st floor offset to R, and single-storey range adjoining below.