Sky Pool | A Transparent Swimming Pool Spanning Between Two Buildings

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Sky Pool is one of its kind swimming pool spanning between two residential buildings, located in London, UK. One thing which sets it apart is that it is transparent. Made from the acrylic material, which has refractive index close to water, the pool seems to be floating midair. The acrylic parts are bonded together which offer almost clear joints and connections.

Image courtesy Eckersley O’Callaghan


The pool connects tenth floor of the two buildings. It has a clear span of 14 meters or 46 feet between the buildings. The thick side walls act as deep beam which are capable of spanning the distance. These walls also bear water pressure from sides and the wind loads. 

The pool has an 8 inch (≈20 centimeters)  thick acrylic frame with a nearly 12 inch (≈30 centimeters)  thick base, having a depth of around 10 feet (≈3 meters). It weighs a whopping 50 tons (≈45000 kgs).


The buildings are acted by various kinds of forces which include earthquakes, winds, uneven foundation settlements, temperature stresses etc. The pool avoids these forces on the buildings by not being rigidly connected to the buildings. Hence it can slide when buildings move relatively, while maintaining watertightness.

Sky Pool Supports Bearings
Sky Pool Supports, Top View and Elevations. Image courtesy Eckersley O’Callaghan

Let us know about these supports in detail. The above illustration shows the locations of the supports in the pool. From the first top view diagram, we can see that the pool has 8 roller supports at each corner which are free to move in any direction. There are two supports at the center line, of which one is roller, and one is pinned. The center roller support is restrained to move in just two directions, while the pin support is restrained for motion in all directions but allowed to rotate.

The next two diagrams show the pool in elevation when the buildings undergo uneven settlement. As the supports are free to rotate, the pool remains safe from such relative displacements.

Sky Pool Bearing Movements
Sky Pool Bearing Movements. Image courtesy Eckersley O’Callaghan

The above illustration shows various scenarios in which buildings can move relatively (bigger arrows). The movement of bearings is shown by smaller arrows for every possible case. Hence for every case, the supports can adjust in such a way that the pool remains isolated from building movements.

The pool went under various analysis simulations taking into account the natural frequencies, water sloshing, water weight, self-weight, temperature changes etc. Structures like the ‘Sky Pool’ keep the structural engineering field interesting and motivate the community to reach newer feats.

Structural Engineers: Eckersley O’Callaghan

Client: Ballymore Group

Architects: HAL Architects

Know more about ‘Types of Supports’ in below video.