Dyffryn Mawr Farmhouse

Dyffryn Mawr Farmhouse is a two-storey farmhouse built in the first half of the 17th century, with its main range oriented approximately east-west. The exterior is made of limewashed rubble and features a central modern porch on the front (south) elevation. The building was re-fenestrated in the early 19th century and has a two-storey single bay extension at the rear. It is likely that the eaves were raised during this period, resulting in a roof with a lower pitch than the original. The gabled, pitched roof is now covered with concrete tiles and has two square gable stacks made of limewashed rubble. The small-pane hornless sash windows have been removed from the ground floor, but they remain on the first floor. At the eastern end of the southern elevation, there is a stair outshut with light, which retains a fragmentary slab roof.

The main range consists of two cells and a hearth passage on the ground floor, with each cell heated by substantial rubble open fires featuring heavy timber bressumers. The fires are chamfered with straight cut stops and fillets. The kitchen fire is now obscured, while the parlour fire shows evidence of a former gable entry on the southern side. The parlour and kitchen were previously separated by a timber plank and muntin screen, which has been recently removed. There is evidence of a large timber door frame on the north rear wall of the parlour, which is now blocked by rectangular cupboards on either side, each retaining scratch moulded, pegged frames from the 17th century. The doors are missing. The farmhouse has heavy beams with medium chamfers and straight cut stops with fillets, and exposed joists with scratch mouldings on the face and sides in the parlour. The kitchen end features stone stairs with a gable entry but no outshut, while the parlour end has lateral entry stone stairs within an outshut. There is allegedly a "priest's hole" located behind the kitchen fire, accessible from a chamber above. The chamber above the parlour is heated by the original gable fire, while the chamber at the kitchen end is unheated. Original pegged "A" frames are retained beneath the modern roof structure. The later rear wing contains a dairy on the ground floor, which has a Victorian quarried terra-cotta floor.