Developing the floating platform to meet the design objectives

The floating platform of the house consists of two parts, the floating elements- responsible for the buoyancy- and the structural frame, that form a stiff base for the development of the house. Its geometrical configuration and the material selection are such to comply with the criteria of lightness, waterproofness, simplicity in detailing, usage of waste materials and sustainability. 

Structural concept of the ReVolt House

To begin with, the floating elements are situated at the lower part of the system, in contact with the water. They are formed into hexagonal modules, in order to be evenly distributed inside the circular outline of the house. In section they are shaped in such a way as to create a catenary dome that reassures their co-operation and their staying in place. This dome configuration of the floating platform causes the peripheral elements to submerge deeper into water, receiving larger water pressure and therefore producing larger support reactions at the points where the loads from the walls are received.  Even more, the dome is the optimal choice in terms of stability, forcing the house to behave as a catamaran in all directions. 

The floating elements, according to their position in the dome, are categorized in 4 different types. In one of the categories, at the periphery of the house, the hexagons adjust their shape to fit with the circular boundary of the construction. 

The draught of the house is minimised by reducing the density of the floating platform, without losing however on strength or ability to withstand water pressure. This is achieved by designing the hexagonal modules along the concept of sandwich panels, where the thin exterior layers and the interior foam work together to produce a strong yet lightweight structure. 

Considering the infill of the floating modules, the idea of replacing a standard foam infill with pressurized air that enables the thin skin of the module to withstand the water pressure, can lead to a stronger, lighter and more sustainable structure. The hexagons are therefore filled with polyethylene terephthalate (PET) bottles for carbonated drinks containing powdered dry ice that turns into carbon dioxide, pressurizing the bottles’ vessels. The PET bottles, due to their shape, are distributed in a hexagonal pattern, and joined together with a compression belt. A thin layer of PET foam is introduced at the upper part and the sides of the modules, to achieve the required shape for each hexagon module.  It must be noted that the choice of PET bottles as a construction element relies to their good strength to density ratio, their low cost, and at to the fact that it reduces the embodied energy of the hexagons, by reusing already produced elements. Moreover, taking into account that, due to the organisation of the plan, the mass of the house is not homogeneously distributed, the bottles provide the flexibility to adjust the weight from the platform and reach equilibrium, by filling the bottles in the problematic areas with sand. 

Floating platform: plan, section, details

Regarding the PET foam, it is a foam material produced from recycled PET bottles, and with higher mechanical strength and better insulating properties from eps or pu foam usually applied in sandwich panels. 

The outer layer of the hexagons consists of a 4mm thick glass fiber reinforced (GFR) polyester surface. This decision is based again on the superior strength to density ratio that glass fiber reinforced polymers (GFRP) show but also to the minimal maintenance costs that they demand and their excellent behavior in water.  In addition, because of their non-corrosive behavior, water pollution is avoided, a case very common with steel pontoons. 

Section of floating module

The structural frame of the platform, out of GFR polyester I-beams, comes on top of the hexagon modules in a triangular grid, and is joined with them to ensure that they work as a unified rigid the structure.