In a 2009 thesis for the Degree of Master of Architecture, we proposed a thermal therapy resort that utilizes rammed earth construction. The conception and design were centred around using rammed earth to minimize the project’s ecological footprint. In contrast to the existing linear process of architecture – where resources are extracted to construct buildings before being discarded as waste at the end of the building’s lifespan – rammed earth can be returned to the ground upon demolition, leaving the natural environment similar to its original state pre-construction. This project would hopefully demonstrate the viability of rammed earth construction in Singapore and inspire greater utilization of this sustainable material.

The proposed thermal therapy resort, incorporating spa treatments, aims to provide a secluded private location for Singapore’s urbanites to get back in touch with nature, rejuvenate and relieve the stresses of urban life. The resort would be located in the Kranji countryside which is far-removed from the urban city and has an abundance of protected natural settings zoned for leisure activities under the URA masterplan. Sun path, topography, vegetation, traffic & noise, and gradient & slope analysis were conducted to find the ideal plot that would also minimize the falling of exiting trees.

The construction of the resort would utilize soil excavated onsite to level the site. Analysis of the soil in Singapore has shown that up to 75% is suitable for rammed earth use and most can be classified as lateritic – making it highly resistant to weathering. The excavated soil would be poured into temporary formwork and compacted with a mechanical ramming equipment before being left to dry, layer by layer. Use of onsite soil would minimize emissions caused by material transport and ensure that the rammed earth can be returned back to its original environment at the end of the building’s life. As rammed earth has a high thermal mass, it can be used to both retain the heat used in the therapeutic areas, and regulate temperatures to keep the accommodation area cool.

The operations of the resort would be reliant on the biomass waste collected from local farms, agricultural plantations and restaurants in the vicinity. An estimated 15-20 tonnes could be collected daily. Pyrolysis would be used to convert the biomass into syngas and bio-oil which would generate heat and energy for the resort, and biochar which can be returned the surrounding farms and lands to fertilise the soil.

To aid the conception of this project, we conducted a few material studies to investigate the properties of rammed earth.

The first investigation brought us to Sekeping Serendah in Selangor, Malaysia where the mud houses featured infill walls made with poured earth – a process similar to rammed earth with the exclusion of the compaction phase. Using data loggers, we tracked the temperature of humidity of the rooms enclosed with the poured earth walls and compared it to a timber house and the control – the outside environment.

The investigation showed that the walls made from earth had the capacity to regulate heat and humidity well, maintaining a comfortable indoor environment for inhabitants. We also concluded that natural or mechanical ventilation is preferred over air-conditioning for buildings made of rammed earth. These properties make rammed earth an extremely suitable material for the proposed project.

The second study saw the construction of 3 prototype rammed earth walls made form locally excavated soil to understand the construction process and possible limitations; test possible protection by incorporating other materials; and investigate the integration of services and creation of openings. The study and prototyping yielded useful insights such as the importance of formwork rigidity and resistance, waterproofing during the construction phase, optimal depth of each layer, and use of chamfering to strengthen rammed earth structures.

With the result of the studies in mind, we conceptualise the design for the project as such:

The front of the project facing the access road would feature a stunning rammed earth wall spanning the length of the main complex.

The complex would feature a garden, café, accommodation area and natural pools. 

The main therapeutic area is composed of a wet area – including a hot, warm and cool pool – sweat rooms, a sensual lounge and a private treatment area. The treatment would conclude with a deck lounge for post-treatment relaxation.