The main building of the Porthgain Brickworks is situated at the bottom of the valley, adjacent to the harbour. The building is referred to as 'Ty Mawr' and was originally the brickmaking building, with drying sheds (now removed) located to the southeast on what is now a small football field, and the kiln (now removed) to the northeast. The brickworks is not shown on the 1st Edition 25" OS Map published in 1889, but its construction must have begun shortly after the survey work for the map was completed, because it is noted as being near completion in 1890 (Davies, 2015: 35). The brickworks utilised slate waste for the production of bricks which was a unique process within Britain at that time. The bricks produced were used extensively within the renovation of Porthgain Harbour (see NPRN 34343), as well as in the construction of the storage bins for crushed granite along the western side of the harbour, some bricks were also exported (Davies, 2015: 42). The scale of the works is indicated in numbers cited by Davies (2015: 53) who records that in 1909 there were 600,000 bricks in the brickyard, 100,000 remaining in the kiln, and 200,000 that had been used for construction within Porthgain itself. The brickworks closed in 1911, with the last shipment of bricks in 1912, and the kiln was dismantled in 1925 (Davies, 2015: 76).

Ty Mawr is a Grade II listed building, with the description of the building as follows: Green granite rubble rectangular structure, externally of two storeys with large cambered-head upper windows, five each side, four to south end. Sides and south end have broad low ground floor openings with timber lintels. There was formerly an open lean-to range along W side and two long low sheds running S from S end. S end has corbelled rough stones vertically up to gable apex, presumably for an intended addition. North end has large lean-to built in two stages, first in stone with arched doorway each end then in brick, single slate roof carried over. These two sections are marked ‘Engine House’ and ‘Boiler House’ on 1896 plan and the stump of a removed square brick stack remains at NE angle.

Ty Mawr is now home to a restaurant within the lean-to on its northern end, and is used for the storage of traditional rowing boats within its main space. The former open lean-to along the western side, noted in the Cadw listing, was reconstituted in 2025 to provide an additional seating area for the restaurant.

Sources include:

Cadw Listed Building 12433: https://cadwpublic-api.azurewebsites.net/reports/listedbuilding/FullReport?lang=&id=12433

Davies, P. B. S., 2015. Porthgain & Abereiddi. A Century of Industry. St Davids: Merrivale.

J. Whitewright, RCAHMW, May 2025.