Advantages of Using Vermiculite

The fireproofing characteristics of vermiculite concrete are recognized nationwide by insurance companies, state rating bureaus and local building officials. Underwriters' Laboratories have assigned up to 4-Hour ratings to systems that employed vermiculite as one of the components.

Vermiculite insulating concrete is easily placed by modern specially designed pumping equipment. Up to 25,000 square feet can readily be placed in one day

Vermiculite concrete can be applied over a variety of bases, allowing architects and engineers ample flexibility in their design criteria. The thickness of the concrete can be varied to permit necessary slope to drain.



Slope to drain systems employing vermiculite concrete and polystyrene vent board provide an economical solution to existing flat roofs with damage due to ponding of water.

Vermiculite concrete has excellent insulating properties. Three inches of vermiculite concrete is equivalent to 1 1/2" of rigid board insulation laid over steel decks. One inch of vermiculite concrete is equal in insulating value to 20 inches of regular concrete. 

Vermiculite concrete is suitable for installation over most structurally sound roofing systems with structural decks of concrete, metal, or wood. Care must be taken to properly vent decks poured over impervious materials.


The term vermiculite applies to a group of minerals characterized by their ability to expand into long, worm-like strands when heated. This expansion process is called exfoliation. The name vermiculite is derived from a combination of the Latin word vermiculare meaning "to breed worms," and the English suffix-ite, meaning mineral or rock. In its expanded form, vermiculite has a very low density and thermal conductivity, which makes it attractive for use as a soil amendment, lightweight construction aggregate, and thermal insulation filler. Expanded vermiculite also has a very large chemically active surface area, which makes it useful as an absorbent in some chemical processes. When vermiculite is ground into a fine powder, it is used as a filler in inks, paints, plastics, and other materials.

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