Oerddwr-Isaf

Oerddwr-Isaf is a small single-storey cottage built of rubble with prominent boulder foundations and irregular rubble gable parapets. The cottage has a corrugated iron roof and a tall chimney on the left gable, featuring plain capping. The near-central entrance consists of a deeply-recessed boarded door with a stone lintel, flanked by small square windows that have 4-pane late 19th-century glazing. There is a similar window, which is unglazed, on the right gable end, with a deep inward splay.

Inside, the two-bay layout likely originally included a croglofft. The central collar truss features one principal that is a probably re-used cruck blade, along with the collar. There is a wide fireplace at the chimney end on the left, with a flat oak bressummer, and the interior has 20th-century partitioning.