Coedtrewernau Mill and attached cottage

Coedtrewernau Mill is a 2-storey mill with an attached 1½-storey cottage to its right, separated by a vertical joint. Both structures are built of rubble stone and have slate roofs, with the cottage featuring a stone stack on the right side; a stack on the left side has been removed. The mill faces south and has openings under wooden lintels. There is a boarded door on the right side, with two windows covered by corrugated iron to the left. In the center, there is a gabled loft loading door, and to its left is a small upper-storey window. The gable end has an irregular opening where the axletree was removed, along with a small opening to control water flow. The wheelpit has been infilled, and the gable is weatherboarded with an opening that has a boarded shutter. At the rear, there is a split boarded door on the left, a shuttered opening on the right, and a small loft window.

The restored cottage has two windows facing south and features a central replacement split boarded door flanked by 3-light windows under brick segmental heads and 2-light half dormers. The rear of the cottage includes a lower gabled projection, with a replacement boarded door to the right and a half dormer above, which formerly had a lower sill.

The mill retains much of its machinery, including the pit wheel, spur wheel, and two bed stones located on the upper floor. The roof has a 3-bay collar-beam design with iron bolts instead of wooden pegs.