Hafod Elfyn (former Natural Environment Research Council Offices)

Hafod Elfyn, formerly the Natural Environment Research Council Offices, is an office building designed in a vernacular revival style. It has a single-storey 'L'-shaped plan with additional accommodation in the roof, and the main range is parallel to and set back from Penrhos Road. The building features roughcast walls and a tall slate roof laid in diminishing courses, which includes small hips, a ridge finial, and an axial chimney on the main range. There are dormer windows on the rear roof slope, metal casement windows on the ground floor, and small pane sash windows in the attic floor of each gable.

The main entrance, located on the long elevation facing the road, is offset to the right and consists of plain timber plank doors set within a deep pink sandstone moulded surround. Although not inspected, it is reported that the building remains largely intact, retaining original doors and brass fittings, including the main entrance doors and corridor doors with bevelled glass panels. Inside the entrance, there is said to be a plaque that reads: 'This research building is named Hafod Elfyn in honour of Professor R. Elfyn Hughes for his contribution to nature conservation and research in Wales'.