Tree-ring dating commissioned by Cymdeithas Hanes Beddgelert in association with RCAHMW. Results reported in Vernacular Architecture 36 (2005), tree-ring dating list 181 (notes by Margaret Dunn, Daniel Miles, and Richard Suggett):

7. LLANFROTHEN, Cae-glas (SH 6274 4571) Felling dates: Summer 1546, Winter 1545/6, Winter 1546/7, and Winter 1547/8
Principal rafters (2/3) 1547(28C, 27C); Mantel-beam 1547(27C); Collar 1546(38C); Screen heads 1545(28?C, 26C); Rear door head/lintel (0/1), Rear wing floor beams (0/2). Site Master: see next entry
An early storeyed house of classic Snowdonian plan-type with a voussoir-headed cross-passage doorway and a projecting end chimney. The cross-passage was fully screened with post-and-panel partitions between the outer rooms and the hall. The first floor was open to the roof with two trusses of collar-beam type and two tiers of cusped windbraces. The principal chamber has a corbelled-out fireplace.
8. LLANFROTHEN, Bwthyn Cae-glas (Cottage) (SH 6281 4468) Felling date ranges: 1497-1527, 1519-49, 1527-56, and 1541-71
Crucks 1530(H/S), 1517(2), 1489(H/S), 1482(H/S); Collar 1508(H/S). Site Master (including previous entry) 1386-1547 BDGLRT7 (t= 8.6 WALES97; 7.9 CEFNCAR1; 7.9 PENGWERN)
A three-bay stone-walled range with two cruck-trusses, latterly used as a farmbuilding. The range has opposed central doorways and splayed window openings. The range is difficult to interpret but appears domestic in origin because the lap-jointed crucks are smoke-stained. This is provisionally interpreted as a secondary dwelling (dower-house) in a Snowdonian unit-system arrangement. The dwelling was probably of crog-lofft (half-loft) type with an open hall/kitchen. The wide span of felling date ranges suggests that two of the crucks were re-used, and that the building is probably coeval with the main house.
9. LLANFROTHEN, Beudy Cae-glas (Cowhouse) (SH 6280 4447) Felling dates: Summer 1703 and Spring 1704
Purlin 1703(44?C); Principal rafters 1702(30?C), 1698(36 plus 1-5C NM), 1672(3+28NM); Collar 1664(H/S). Site Master 1578-1703 BDGLRT4 (t= 8.0 BDGLRT5; 5.3 DMCC-T9; 4.9 MIDHSQ01)
A detached cowhouse of three bays with a down-slope siting. The cowhouse was entered at the lower gable end; the upper gable having a loft doorway. The two tie-beam trusses have lapped apexes and `wavey' collars. The tethering arrangements have been lost. Richard Suggett/RCAHMW/September 2006.