Tŷ Cerrig is a cruck-framed hall-house. Originally half-timbered, the walls were later encased in stone. The crucks are very heavily smoke-blackened.
In the 16th-17th century, a fireplace was inserted into the hall, blocking what must have been the passage, and creating a lobby entry. Over the fireplace is a characteristic tall, square Denbighshire-style chimney.
No upper floor was ever added, but the 'hall' had a ceiling inserted.
The exceptionally heavy smoke-blackening over the outer room suggests some sort of industrial use, possibly a blacksmith's shop.
Dendrochronology results: from the Oxford Dendrochronology Report, Miles and Bridge. Oak from four crucks was sampled by dendrochronology experts, and the dates obtained suggest that Tŷ Cerrig was most likely built in 1501.
Location - Tŷ Cerrig, Llanfwrog, Denbighshire.