- Project plans
- Project activities
- Legislation and standards
- Industry context
Last edited 23 Feb 2017
Rubble trench foundation
This is a variation of the trench fill foundation, and is a traditional construction method which uses loose stone or rubble to minimise the concrete requirement and improve drainage. It follows the same approach as a French drain, with a trench that is filled with crushed stone letting any water drain down and away from the foundation.
This approach has been used in various guises for thousands of years but it was popularised in the 20th century by the architect Frank Lloyd Wright, and has been promoted as being more environmentally-friendly than other foundation types.
The bottom of the trench should slope with an even descent of at least 3 cm for every 1 m of trench, which diverts the water towards one point, from which it can be diverted away through an outlet or to a dry well.
The trench should be lined with a geotextile material to prevent the surrounding soil from clogging up the trench and outlet. It is then filled with angular and washed stones of average size 2.5-5 cm, with them being compacted at every 30 cm layer using either a pneumatic or hand-powered tamper.
When it reaches around 20-30 cm below grade, the larger blocks of stone can begin to be built up as a continuous wall.
 Find out more
 Related articles on Designing Buildings Wiki
Featured articles and news
The structural feasibility of modular high-rise buildings.
BRE conference on ways of providing and maintaining quality indoor environments.
CDBB publish foundational definitions and values to guide the development of the National Digital Twin.
Despite the reduction in staffing, most users remain satisfied with the service.
We run through the top 37 styles in history - but how many would you recognise?
Improving approaches to risk in the built environment sector.
Megatrends: Smart Building Technology
Share your BREEAM knowledge to help improve the industry.
Are you innovating without realising it?
Is timber a carbon source rather than a carbon sink?