Brynberian Cottage — Over-Slate Thatching in the Preseli Hills

This ruined cottage at Brynberian in the Preseli Hills, Pembrokeshire, presented an unusual challenge: an over-slate thatching project, where a thatched coat is laid directly over an existing slated roof rather than a bare rafter structure. The technique is a genuine vernacular Welsh tradition, once used to extend the life of ageing slate roofs cheaply using locally available straw.

Pembrokeshire Thatch and Carpentry used combed wheat and drum-thrashed landrace straw — an older, taller-strawed variety closer to historic crop types than modern short-strawed wheat — to build up the courses over the existing slates. Hand-made straw rope was twisted on site and used to fix the courses and ridge in the traditional manner, working up from the eaves in stages typical of historic Welsh thatching practice, with clom (a traditional Welsh daub) used to dress and seal junctions and detailing.

The completed roof returned a derelict cottage to a weatherproof, traditionally finished state while preserving the evidence of its earlier slated roof beneath — a layered record of the building's repair history that is typical of vernacular Welsh roofing and rarely seen restored with this level of historical accuracy.