Eco foundation system from Clayboard, how it works and why do I need it?
How Clayboard® eco foundation system Works
Clayboard® is a unique, environmentally friendly void former and
eco foundation system developed by Dufaylite.
Clayboard® has a biodegradable honeycomb core set between
lightweight polypropylene facings.
When dry, Clayboard® eco foundation system is strong enough to
support the weight of wet concrete and steel reinforcement.
Water is introduced to the Clayboard® core once the concrete is
set, degrading the Clayboard® honeycomb centre which will
ultimately lead to the creation of a void. This space will
accommodate clay expansion without exerting undue pressure on the
structure above.
The resulting void continues to accommodate natural soil
shrinkage and expansion.
The Natural Threat of Clayheave
The damage risk posed by natural shrinkable clay soils is well
known to engineers and builders. Changes in the soil water content
cause shrinkage or expansion which, if not properly accommodated,
can exert intolerable pressure on any building standing on the site
causing structural damage when clay heave foundation systems are
not present.
Shrinkable clay soils are present all around the world. In the
UK, these soils can be found deposited throughout the country and
most commonly in the South East, falling in an area between Exeter
and Hull. However climatic changes are now affecting similar soils
in the North, making foundation systems much more important as a
clayheave solution.
With the increasing occurrence of droughts, geological
conditions have worsened with clay soils compacting and drying out.
Tree roots search out an increasingly deeper and lower water table,
and rainfall has little impact.
Evaluating Soil Types And Risks
Soil analysis is essential to determine the suitability of
potential sites and the required foundation system protection.
Shrinkable soils are classified by their Plasticity index, which
can itself be affected by changes to the immediate environment. For
example, the removal of a single tree can add as much as 150 litres
of water a day to soil. The blanket removal of trees will make
exaggerated clayheave almost inevitable.
Clayheave assessment should be carried out by a soil testing
laboratory. The depth of void required to protect a structure from
ground expansion and contraction is then specified by the soil
engineer.
We recommend you refer to the appropriate Codes of Practice, BRE
Digests and NHBC Guidelines for technical information on shrinkable
soils and their structural implications.
Clayboard® eco foundation system has won British Board of
Agrément Certification for all types of residential, commercial and
industrial buildings.
Who should use our eco foundation system product
- Architects
- Ground workers
- Structural Engineers
- Housing Associations
- Home Builders
- House builders
- Civil engineers
- Building Control Officers
