Building Case Study: Holland Park Rammed Earth Eco Building
Key facts:
Holland Park Ecology Centre, Ilchester Place, London, W86LU
Sub-contractor: EcoCarpentry Design and Build
Architect: Munkenbeck and Partners
Consultant: Rammed Earth Consulting CIC
Client: Royal Borough of Kensington and Chelsea
Context
The use of compacted earth as a building material is common in many countries. Despite its apparent abundance, use of earth as a building material remains relatively rare in the UK.
The rammed earth Eco Centre in Holland Park was built over ten days in the grips of sub-zero temperatures, by a team with minimal experience but maximum enthusiasm.
Materials and costings
The building was composed of Rammed Earth and Timber. The Earth material was a grey brick clay mixed with 'twenty to dust', a red crushed limestone. This mix was prepared off site and brought in in bulk bags. This not considered a large job, but still 50 tonnes of mix was needed. The materials were prepared off site, brought in in bulk bags.
In terms of costings other than materials, there was labour for the ten days, including a driver to bring in the materials, and a front-end loader with a ticket to drive the material onto site. Rammed Earth is a material that can be used in many applications, but the considerations of other costings such as these must be taken into account at each unique site. For example. in central London where this project took place, labour is expensive but very flexible. In a more rural area, labour may be cheaper but sourcing a front end loader may have been much harder.
Building
The team had to batch load into a mixer with water to get the moisture content right, then bucket and barrow to the formwork. Formwork was done by a man-handled system by someone hired in specially for the job. 14m lengths were used to build 'invisible' angled joints to minimise the working area.
Lessons and questions
How do we continue to ensure builders and contractors receive credit and acknowledgment for their projects? Architects often get a lot of the praise, but these other parts of the project are important to acknowledge, particularly in Earth Building that requires specialist knowledge.
When could it be necessary to use stabilisers, and what are the concerns with using concrete for this?
Watch the video by NBS to explore these questions and explore some other high-profile successes and failures.
