Difficult to rely on 3D printing alone for Singapore buildings

I commend Singapore researchers and organisations that are developing new applications for three-dimensional (3D) printing, especially in traditional construction, where material wastage and productivity present challenges (“How Singapore researchers 3D-printed a bathroom unit in 12 hours”; May 22).

Nanyang Technological University’s researchers have found a way to build prefabricated bathroom units, without fittings such as pipes, in 12 hours with a 3D printer. They eventually hope to roll out the technology for a housing project.

There are challenges, however, when it comes to putting in place 3D printing in the construction industry.

In land-scarce Singapore, most buildings are high-rise.

As such, prefabricated or precast building parts have to be hoisted during installation. At present, 3D printing for building applications is inappropriate for this.

As the technology is limited largely to short-span concrete structures, these parts are vulnerable to stresses from hoisting and being stacked above one another.

While 3D-printing a bathroom unit takes only 12 hours — almost half the time needed for conventional concrete to harden — it could cost substantially more than conventional precast bathrooms.

This is because the capital costs of commercial 3D printers for construction may be higher, since they are not used widely.

Moreover, a 3D-printed bathroom is presently unable to accommodate concealed electrical, plumbing and sanitary pipes, which are standard features of public housing projects.

This reduces the prospect of 3D-printed bathroom units being widely adopted in public apartments.

To overcome these challenges, a combination of 3D-printed and conventional building materials could be used to build units that are structurally sound, fast to construct and flexible in accommodating hidden pipes.