Collapsible Void Former
VOID-TEK arrives on site flat packed only 31mm high. Simply lift into an upright position. Pull down the support flaps and lock into deployed position.

Product Documentation


VOID-TEK is a collapsible void former which is used to protect concrete structures from the effects of ground heave, typically associated with clay soils. It is supplied in a thickness which is suited to accommodate the plasticity range as identified.

The product consists of folding polypropylene sections which are bonded together to produce a robust structure which can withstand a load implied by up to 900mm thickness of concrete. Its unique structure means that it arrives on site just 31mm thick and is deployed in seconds to produce the required Void former.

When the product collapses due to the upward pressure caused by
ground heave, the VOID-TEK sheet will compress to a thickness of
just 31mm creating the required void.

The VOID-TEK system is complimented by a range of ancillary products including VOID-TEK Heave protection Sheet for side heave applications, VOID-TEK Tape, VOID-TEK Central and Interlocking fins and VOID-TEK Pile Collars.


VOID-TEK is used beneath suspended structural concrete slabs to create a void which allows ground heave to occur without adversely affecting the integrity of the concrete.

VOID-TEK can also be ordered and configured to specific size requirements for use beneath reinforced concrete ground beams and pile caps.

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VOID-TEK Presents some unique advantages over conventional void former systems as follows:

  • Reduces dig – saving labour & muck away costs.
  • Flat-packed on arrival – vast reduction in transport costs and less space needed for storage.
  • Deploys in seconds – quick to assemble, less breakage and easy to cut with minimal mess.
  • Polystyrene free & high strength – made from polypropylene fluted board – no crushing/snapping & better for the environment.

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