Its front wall, built from random rubble and facing south, still holds an earthen core behind it. The entrance recess is spanned by an iron lintel, and the structure corbels inward towards the rear, a technique where courses of stone are stepped progressively inward to form a rough vault or closing, avoiding the need for a keystone or timber centering.

Lime kilns were a common feature of the Irish agricultural and building landscape from at least the seventeenth century through to the late nineteenth. Limestone was burned at high temperatures inside the kiln, producing quicklime that could be spread on fields to reduce soil acidity or slaked with water for use in mortar and whitewash. The survival of the earthen core at Glennakeel is a small detail worth noting; many kilns of this type have lost their internal material entirely through collapse or clearance. What makes the Glennakeel site additionally interesting is that a second lime kiln, recorded separately, stands roughly 200 metres to the north, suggesting the area once supported enough demand, whether agricultural or constructional, to justify more than one such facility within a short distance of each other.