Limestone roofs in Bermuda

The islands of Bermuda sit on a long extinct volcanic seamount in the part of the North Atlantic known as the Sargasso Sea. The islands were created by mid-ocean volcanic eruptions about 35 million years ago. Today the rocks above water  are almost exclusively limestone, with the basalt volcanic core below. So Bermuda has igneous and sedimentary rocks.

Houses in Bermuda all have white stepped roofs. Bermuda has no fresh water springs, rivers or lakes so the design of the roofs is essential for collecting rainwater. This was first introduced 400 years ago. Many of the houses are made of limestone and painted in pastel colours with a white roof with steps. Bermuda has a lot of rain and the steps on the roof slows down the heavy rainfall which collects in the gutters and stored in a tank under the house. Each home is self sufficient and there is no mains water and no water rates. House building regulations state for each square foot of roof, all houses must have eight gallons of tank space. 

The roof is made of limestone, which is heavy enough not to be moved by hurricanes. In the past it was covered with lime mortar, which has antibacterial properties. Now the mortar has been replaced by white paint, this reflects ultra violet light from the sun and this helps purify the water. 

See BBC article from 2016.

In 2023 I visited Crystal Cave on Bermuda.