After printing, the bathroom is furnished with toilet fittings to become a pre-fabricated unit, ready for use in construction projects, according to researchers from Nanyang Technological University in Singapore who have developed the system.
This could potentially help firms build prefabricated bathroom units (PBU) about 30 per cent more quickly and 30 per cent lighter than current PBUs.
In the past four years, the team focused on developing a special concrete mix which is fluid enough to flow through the hoses and print nozzle, yet can harden fast enough so that the next layer is able to be printed on it.
The printing process takes half the time needed in the construction of a conventional bathroom unit that uses concrete casting. The fittings, tiling and finishing will typically take another five days.
PBUs are usually cast from concrete and completely preassembled offsite with all necessary finishes and fittings, ready to be lifted and installed in abuilding project.
By shifting most of the fabrication off-site to the controlled environment of a factory, PBUs yield time and manpower savings of about 60 per cent, compared to on-site construction which was the practice prior to 2014.
To enable printing, the team also had to develop new printing and control systems which could match the flow rate of the nozzle to the hardening properties of the concrete.
The printing was then carried out in a single build using a 6-axis KUKA Robotic arm, which has a reach of about 6 metres in diameter.