Slater & Gordon is representing several homeowners in the north-western and western suburbs whose newly built houses are cracking and twisting.

Lawyer Robert Aurrichio blames a particular type of concrete slab foundation, known as a "waffle slab", claiming it's risky to use in the volatile soil conditions in the west.

"We've spoken to a number of experts who believe that [the waffle slab] needs to be designed with adequate drainage to cope with the variable nature of the soil in the western suburbs," he said.

The waffle slab design reinforces concrete using a steel grid with polysyrene cubes placed between the lining. It maximises efficient use of concrete and requires less material than conventional flat slab designs.

Mr Aurrichio said houses sitting atop waffle slabs in the western suburbs, where the clay layer is deeper underground, seemed to be "heaving" with soil movements due to this year's heavy rain.

Archicentre general manager David Hallett said waffle slabs had been widely used for more than a decade across Melbourne's western growth areas due to the high volume of new housing estates.

"In suburbs like Caroline Springs, areas around Burnside, Tarneit, Werribee and Melton, the simple fact is that there's been thousands of these buildings built over the last decade and typically more and more have been with waffle slabs," he said.

But Mr Hallett disputed Slater & Gordon's claim that building cracking was related to a particular design of concrete slab foundation.

He said foundations for any new building needed to be designed to suit the soil conditions of the site.

Master Builders Association director Brian Welch said the industry would be concerned if there was any evidence to support the allegations that homes in the west were cracking due to their waffle slab foundations.

- with Dan O'Sullivan