Porth-y-Twr, including Gateway & South Tower

Porth-y-Twr is a Grade I listed bell-tower, which is a large two-stage octagonal structure featuring a moulded plinth and a moulded course before the set-back bell-stage. Although it was ruinous and roofless in old photographs, it now has a corbelled flat parapet. The bell-stage includes large pointed openings that were originally longer but are now partially blocked, complete with hoodmoulds. The lower stage has a lancet window on the east side and a pointed moulded doorway on the north side, which includes column shafts and a hoodmould. The doors are studded planks. There is a southeast stair tower that slightly projects on the upper stage and rises to a restored octagonal turret. The south side of the tower is obscured by an attached gateway.

The gateway and south tower, added to the south, are constructed from rougher rubble stone and feature a corbel table below the former battlements, which are now in ruins. The rounded south end has a higher corbel table. The east front displays a large segmental pointed arch over the roadway, with a small blocked doorway to the right and a loop above it. Adjacent to this, the south tower has one high window and a rounded south end with a Close Wall attached to the southwest. The west front features a window at an upper level and a large pointed light to the left, just before a change in the level of the corbel table. To the left, there is a segmental-pointed large arch over the roadway, and above it, to the left, is a small window that has been robbed of ashlar.

The southern range is roofless, but within the gateway, there are two portcullis slots and a double archway on the north side, which has been robbed of ashlar, leading to a half-round recess with a narrow round-headed doorway. The south side has a round-headed narrow doorway as well. Both doorways feature studded plank doors with iron strap hinges.