Limestone has been a source of construction material in Gibraltar since the very first city was built in the twelfth century. The Arab chronicler Ibn-Juzayy commented how the white houses of Gibraltar contrasted against the red sands that were still visible in those days of the fourteenth century. Limestone has therefore been traditionally used as a raw material for mortar, used in construction. Lime Kilns, which cooked the limestone to make lime, have been around since medieval times for the production of lime mortar for construction purposes.
They were also used extensively in the 18th and 19th Centuries, and Gibraltar’s lime kilns date from this time. There were many kilns located on different parts of the Rock, but today there is one left, located on Willis’s Road. Three types of lime were produced: White lime (used in agriculture), Slaked lime (used as weak building material) and Quicklime (used in construction works).
The latter was produced by heating crushed rock up in a kiln. The end product was a very corrosive substance that was used in the old days by the authorities to dispose of bodies quickly. Quicklime was also used to make whitewash which was regularly used to paint houses and patios, a practice that seemingly goes back to the days of the fourteenth century when the Arab chronicler described his view from the Bay. Lime Kiln Steps in the Upper Town takes its name from the activity of lime production.
Limestone and lime kilns were an important economic commodity that generated activity in many trades such as stone masonry. The need for lime stone and lime mortar in Gibraltar created a thriving group of trades and industries working with lime, and also a number of related activities such as charcoal vendors who supplied the fuel for the kilns.