Liitle Lligwy is in two sections, the older being late medieval, claimed by Fox and Raglan to be "The only example of a mediaeval one-roomed house open to the roof in Monmouthshire" (Part I, p.90). This house may date from the early C16, but it was extended in c1610 by a taller and larger block when the older part was demoted to being a service wing. This section has now been abandoned other than for storage. The medieval house appears to have been open to the roof, and to have had a floor inserted in the C17.
Source: Cadw listing description
RCAHMW 2012