The bog had kept the timber in a condition that open air would have destroyed within years, which is part of what makes the find unusual. The drain has since been filled back in, and the timbers are now held by the landowner rather than removed to any institution.

A fulacht fia is a type of site found widely across Ireland and Britain, typically consisting of a horseshoe-shaped mound of fire-cracked stones beside a water source and a trough, usually cut into the ground or lined with timber or stone. The standard interpretation is that stones were heated in a fire and then dropped into the water-filled trough to bring it to the boil, though what exactly was being cooked, or whether the structures served other purposes entirely, has been debated for decades. At Garranes, the trough survives as seven pieces of timber: two large rectangular planks and five smaller assorted pieces. The larger of the two main planks measures roughly 0.9 metres long, 0.34 metres wide, and 0.08 metres thick; the second is slightly narrower and a little shorter. Both appear to have been cut from near the outer edge of a tree trunk, since one face of each plank carries a slight curve, the ghost of the original wood's shape. The site sits to the west of a stream on the lower slope of the mountain, which is exactly the kind of topography these sites tend to favour, close to a reliable water source and on ground that holds moisture.