Referencing and Marking for Fabrication of Prefabricated Bathroom Units

Prefabricated Bathroom Unit (PBU) is a bathroom unit that is pre-assembled off-site, complete with finishes, sanitary wares, concealed pipes, conduits, ceiling, and bathroom cabinets, before it is delivered and installed onsite.

At different steps of the fabrication process for PBU, reference lines and markings are required to assist with the accurate installation of concealed pipes, tiles, carpentry and other bathroom fittings. These activities are repetitive and often require additional manpower to help with using measurement, marking or lining tools. Also, the reference lines and markings are done separately by the different trades, and this could result in discrepancies.

Once the installation is complete, the visible reference lines and markings are removed for aesthetic reasons.

As the fabrication plant owner, Greyform is interested to lead the streamlining and automation of the process of drawing reference lines and markings. The process could be streamlined into three stages:

1. After carcass production – for plumbing
2. After waterproofing – for tiling or marble installations
3. After tiling and marble installations – for all other trades, such as carpentry and bathroom fittings

We are interested in tools (for example, laser devices), methods, or robotics that can improve the process of producing reference lines and markings. Note that the lines and markings need to be done in stages. We would work closely with innovators to identify and implement the required changes in the fabrication process for the successful deployment of this new tool, method or robotics solution.

The following are some key considerations or specifications:

• The solution must be easy to use for low-skilled workers.
• It must be compatible with Building Information Modelling (BIM) to allow for the extraction of reference data from architectural drawings.
• The resulting reference lines or markings must fall within an accuracy tolerance of ±3mm.
• For the tiling purposes, the solution should be able to produce reference lines at 10mm or less from the corners, depending on the tile thickness.  
• The reference line thickness must be less than 2mm, but have good visibility on different surfaces, for example, concrete, tiles, and wood. 
• The solution must reduce the total time taken to produce reference lines and markings to less than 30 minutes, including setup and measurement.
• If it produces ink-based lines and markings, the ink must be erasable and not leave any residue stains.

 The solution should include a digital interface to carry out simplified programming of the solution based on the PBU to be fabricated.

An innovative tool, method or robotic solution can produce reference lines and markings in less than 30 minutes in total per bathroom unit with minimal human intervention. The solution ultimately saves time and reduces the reliance on human workers, thus, improving the quality and consistency of installations while reducing defects and reworks. 

If the solution is proven to be successful, it could be adapted to other offsite fabrication processes.