Y Garn, Llanychaer, is a gentry house dating probably from the early 17th century. It is one of the best surviving examples of the massive round chimney set on a side wall, a particular feature of Pembrokeshire. Peter Smith suggests a ground-floor hall house, a single range with lower eaves than at present, originally thatched.

It has a three room plan with a cross passage to the south of the main hall with a massive east side fireplace and the lateral outshuts, characteristic of this house type, on both the east and west sides of the hall. The pointed south door of the hall and the blocked plain door in the same wall gave onto an unheated upper end room, possibly a parlour or service room. A timber partition divided the cross passage from the lower end lofted section, now the kitchen.

The hall is single space with 3 large oak collar trusses, the principals curved and resting on tops of walls, except the south pair which rest on renewed cross beams over the outshuts. The north truss was concealed by a plaster partition (with bramble laths), but has been exposed by setting back the partition just behind. On the east wall there is an exceptionally deep square fireplace with a massive timber lintel and stone jambs.

A range to the north is possibly an early byre, much rebuilt, and converted to accommodation.

Reference: Cadw listed buildings database.