Basements built under windmills

In some of the windmills built in the late 18th or into the 19th century, a basement space was built under the working floor of the mill tower. Advanced masonry skills allowed creation of basements that used less material than the solid fill under the working floor that was elevated by some 10 feet above the surrounding ground level. Basements provided extra elevation for the sails and working floor in addition to a substantial storage area.

The entrance to the basement is right under the juice trough opening at Hope & Carlton Land. The basement entrance under the juice trough opening at Hope & Carlton Land.

Purposes of elevating the windmill

The working floor of a windmill was always built above the factory to allow for gravity fed delivery of the cane juice. By being slightly elevated, the windmill was also better situated to catch the breeze. In some sites, especially on St. Croix’s flatter south shore extending all the way to the west end of the island, a substantial foundation was needed to provide proper height. In later years of construction, instead of filling the foundation with rubble, basements added underneath the mills provided height for catching breezes, elevation for gravity feed for cane juice and a storage space underneath the mill.

The storage space under the Two Brothers mill, looking west from under the tower. Storage space under the Two Brothers mill, looking west from under the tower.

Where are the windmill towers with basements?

At least seven locations incorporated a full basement into the windmill. Basements under the full extent of the working floor are found at Cane Estate (WE), Diamond-Keturah (CQ), Enfield Green (PQ), Hope and Carlton Land (WE), Marienhoj (EA), Two Brothers (WE), and Williams Delight (PQ). All these mills are located in relatively flat areas on the south shore. Another basement is found in the hilly area immediately east of Christiansted at The Sight (EA).

An entrance door to the basement at Hope & Carlton Land. An entrance door to the basement at Hope & Carlton Land.

One of the entrances to the Two Brothers basement is partly blocked by rubble. One of the entrances to the Two Brothers basement is partly blocked by rubble.

One of the side basements at The Sight mill. One of the side basements at The Sight mill.

When do the windmills with basements appear on maps?

While not appearing on the original printing of the Oxholm map in 1799, the windmill at The Sight is prominently included on the 1820 revision to this map, apparently as a maritime navigation aid. In contrast, the mill at Enfield Green  is depicted on the Oxholm’s map published in 1799, the only mill with a basement on this pre-1800 map. The windmills at Hope & Carlton Land, Marienhoj, and Williams Delight are not depicted on any of the historic maps. Of the remaining windmills with basements – Cane, Diamond Keturah, and Two Brothers – all appear on the Parsons map along with animal mills depicted on the 1799 Oxholm map.

The center pillar at the Two Brothers mill supports the mill’s working floor above. The center pillar at the Two Brothers mill supports the mill’s working floor above.

The apparent relatively late development of windmill basements suggests that the need, idea, or skills for creating the basements had not arisen until after the turn of the 19th century. The use of a basement for a windmill is not unique to St. Croix, as the windmill at Catherineberg on St. John included a basement. This mill is located on the central plateau of the island. An animal mill, but not a windmill was depicted on Oxholm’s 1780 map of St. John at the Catherineberg estate.

The center pillar supporting the basement and mill above at Hope & Carlton Land mill. The center pillar supports the basement and mill above at Hope & Carlton Land.

The typical design of the windmill basement

The design of these basements was a central pillar, typically round or with eight sides, that supported an arched opening in all directions to the outer wall of the basement. Several windows as well as a doorway provided light, ventilation, and access to the basement. In addition to this, a passageway led from the basement, which was directly underneath the working floor of the mill, westward to beyond the western edge of the main entrance to the mill tower. This passageway was surmounted by a ramp way accessing the working floor of the mill, with side ramps reaching to the ground to form a “T.” Additional storage space was accommodated under each side of the T-ramp, providing extensive storage under the windmill.

The ceiling of the basement under the working floor arches to support the tower above it at Two Brothers. The ceiling of the basement under the working floor arches to support the tower above it at Two Brothers.

Storage space under the Hope & Carlton Mill T-ramp. Storage space under the Hope & Carlton Mill T-ramp.

The exceptions: The Sight & Enfield Green

The basement structures at The Sight are the most different from other mills that incorporated basements into their construction. The windmill at The Sight has three spaces that stretch east-west under the mill, each several feet wide and several feet high. Only the center of the three spaces stretches the full width of the mill. Given the size of these openings, they may have stored the sails of the mill when the mill was not in operation.

The main basement at The Sight mill goes directly under the center of the windmill tower. The main basement at The Sight mill goes directly under the center of the windmill tower.

The basement at the Enfield Green mill also differs from the other basements. Instead of the usual central pillar arch, in which a central, octagonal pillar expands at the top to meet the outer walls on all sides, the basement of Enfield Green was constructed using two central, rectangular pillars supporting the mill floor above.

Some may think the basement area of the windmill at Canaan (NB) may be another exception. However, given the rough surface treatment of the stonework in that space’s interior, it is likely that this space was carved out after the windmill was decommissioned and converted into a residence.

Some remaining questions about the basements

Basements under windmills present an interesting curiosity about their inclusion in these windmills. Certainly, the windmill used less material to be constructed by including the basement. As well, additional storage space was created. This leaves questions about the engineering and masonry skills required to effectively create a basement that would not jeopardize the operation of the mill by collapsing. What was the storage space used for?

What is the purpose of this alcove near the doorway into this basement at Hope & Carlton Land? What is the purpose of this alcove near the doorway into this basement at Hope & Carlton Land?