The stable/granary/cow-house range is a stone-built early-mid 19th century `L? shaped range, which includes a stable with granary above, reached by an external stone stair at the south-east gable. At the north-west gable-end a single-storey, `L? shape cattle range and lean-to adjoins. All the roofs have pegged lap-collar trusses with morticed apexes, supporting two pairs of side-purlins, a diagonal ridge with pegged slates and grouting over. The ridge slates have interlocking slates held in place by grouting. Another feature of its roof are the original swept valleys between each unit.
The stable has cambered brick arches to its doorway and flanking windows, while the granary with external stone stair, has timber lintels to its openings with frames containing holes for horizontal ventilation grilles. It has two windows to its west front and a north gable opening. The interior has some surviving sawn softwood stall-posts and mortices for former timber rails with vertical boards (see drawing), to house 4 horses. Its sawn-softwood joist ceiling has a long ceiling-beam to which the posts are attached. Some of these posts retain cast-iron bridle gear supports and hooks. The former mangers do not survive, and it now has a concrete floor. The cow-houses consist of two units, each with two similar roof-trusses. Each unit has a central entry, with cobbled floor, probably with cattle tethered facing the end walls (no tethering survives), where the ventilation-slit would cast some light. A lean-to at the north-west, probably used for calves, has its own west doorway and a ventilation-slit to north. The unit's original entrances to east and north have been widened with eaves raised, in the 20th century, to allow machinery access for muck clearing.

The documentary evidence from the 1843 tithe map and apportionment shows similar building shapes as today and that they were already two farms. `Trehellin? (Trehilyn-West) rented by Anne Richards is shown as a holding of 26 acres, and `Trehelling? (Trehilyn-East) as a farm of 146 acres owned and occupied by Stephen Crunn. The farm `Trehelling? relates approximately to the present Trehilyn-East. There are separate `homesteads? noted, as existing, and both have mixed arable and pasture land, with some outlying cottages included. The outline of these buildings, are also shown on the OS map, 2?:1 mile, dated 1814, and Trehelyn-West is similar to today, while Trehilyn-East appears to differ. This provides a building or re-building date for Trehilyn-East buildings, of between 1814 and 1843.
Visited, prior to conversion, initiated by Gill Wickenden the builder, Geoff Ward, 16/02/2011.