Main Building At Upper Mills

The Main Building at Upper Mills is a former mill building, now used as offices, constructed in 1875 for R.S. Davies, a cloth manufacturer. It is made of red brick with stone dressings and features a Welsh slate roof. The building is three storeys tall with an attic and includes a four-storey tower on the west side.

The west front showcases a ten-window arrangement with segmental arched casement windows that have stone sills, interrupted by an off-centre tower. This tower has paired sash windows on the third floor, topped with a pointed arched panel bordered by stone moulding, which extends to form a pointed hoodmould above a circular window on the fourth floor. The tower is capped with a sprocketed and hipped roof, featuring brick eaves decoration, lucarnes, and ironwork cresting. The main block has plain stone banding and sloping attic windows in a mansard roof.

The rear of the building mirrors the front with a ten-window fenestration. The ends of the building have coped gables and single window casement fenestration. There have been some 20th-century alterations to the ground floor. The interior has not been inspected.