Rubble Trench Foundations 

 

Background: 

• Was used by famous American Architect Frank Lloyd Wright in the design of low-cost earthquake proof foundations, such as the Imperial hotel in Tokyo that survived the devastating earthquake of 1923. 

• Is commonly used for railway track construction as well as for the foundations of building cranes. 

• Gravel and Recycled brick / rubble is sourced from dumpsites, cleaned and sorted to use in rubble trench foundations.  

 

Benefits: 

• Is a use of local “free” material.  

• Can contribute to environmental clean-ups, as building rubble is often dumped illegally. 

• Helps to reduce landfill at municipal waste sites.  

• Helps in creating addition work on site. 

• This construction method eliminates min 75% of concrete typically used in foundation design. Note that: 

• Concrete production is harmful to the environment and is said to be responsible for between    5 -8% of greenhouse gases. 

• Concrete is a costly material. 

 

Technical information: 

• The rubble trench is filled with smaller rubble/gravel around a filtering drain pipe at the bottom of the foundation, followed with larger fist sized pieces packed firmly ready to form the base of the wall. 

• Is suitable for a wide variety of soils including clay soils, but its use would still be subject to the specific design and on-site conditions. 

• Once one has sourced and cleaned the rubble, it is a very fast way to construct one’s foundations. 

• Trenches are typically lined in a geo-fabric filter cloth to protect the trench from filling up with any fine material. 

• Gravel is also suitable for use and is well tamped into place. 

• A concrete ground beam is finally cast to cap the top of the foundations. The beam can be cast to finish around 50mm below the finished ground level.  

 

Company Track record/examples of work: 

• House Rissik. Prince Albert, Karoo, 2023-24  

• House Mendel, Hout Bay, Cape Town, 2021 

• Staff houses, Stanford Valley Farm, Western Cape, 2008 

• Upgrade of Nieuwoudtville Caravan Park, Namaqualand, 2004-2007, which won Silver 2005 in the Holcim Awards for Sustainable Construction in the Africa Middle East region 

• House Perry 2007 - in Masipumalele informal settlement, Cape Town