Dramatically perched atop a small crag in Fladdabister are two 7m in diameter drystone circular limekilns. Used as a render for mortar and additive to reduce soil acidity, they continued in use from the 19th into the early 20th century. At this point the kilns were likely abandoned as lime could be more readily purchased due to industrial scale production on the mainland. Quarry holes can still be seen all around the site along with two rectangular buildings, the larger possibly associated with the kilns. There are also the remains of boat noosts at the southern base.
Known as draw kilns, they operated by layering chunks of limestone between combustible material heated to as much as 1000 degrees celsius. The resulting lime was then extracted through draw holes found along the bottom of the structures.
The site has been scheduled, of national importance due to its fine preservation as an example of resource extraction on a local scale. It is also deemed of interest because of its context within the subsistence economy of 19th and early 20th century Shetland.
Information on the scheduling can be found here. Directions to the site and a larger Fladdabister walk can be found here. Getting to and from the kilns is a rather easy amble, continuing along the coast for wonderful views and sea life is only slightly more rugged but highly recommended.