Most of the national codes of practice do not give characterization and cla
ssification of expansive soils, in spite of expansive soils being distribut
ed very widely over almost all geographical locations in the world, causing
distress to the structures founded on them and discomfort to the users. A
simple user-friendly approach based on the free swell ratio, defined as the
ratio of the sediment volume of soil in distilled water to that in carbon
tetrachloride or kerosene, is formulated considering the compatibility of t
he results with oedometer free swell tests and the soil clay mineralogy. St
atistical illustrations are provided which clearly indicate that while the
assessment of soil expansivity based on index properties is an overestimati
on, there is a consistency in the classifications based on oedometer test r
esults and the proposed approach. It is recommended that simple approaches
such as the one proposed here to classify the expansive nature of soils are
entered into standard codes of practice.