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What is Vermiculite Board?

Kay Paddock
Kay Paddock

Vermiculite board is a fireproof product made from vermiculite and treated for use in a variety of ways. It is often used as firebrick, shelves for kilns in which things like ceramics are fired and hardened, and in industries that work with substances like molten metal and glass. Vermiculite board also provides insulation and deadens sound. This product is used frequently in construction for its heat-resistant and insulating properties. It is also often found in furnaces, loose insulation, and potting soil and growing mediums for gardening.

This board is made from vermiculite, a natural mineral that must be mined. Vermiculite is typically mined in open pits and then put through a process called exfoliation. Exfoliation heats the mineral, causing the water trapped inside it to turn into steam. This expands the vermiculite and changes it into the porous, lightweight material that is used in products like vermiculite board. The board can generally withstand temperatures of up to almost 2,200 degrees Fahrenheit (1,200 degrees Celsius), which makes it useful in the steel industry, in furnaces and in things like aluminum production.

Vermiculite is a natural mineral that must be mined.
Vermiculite is a natural mineral that must be mined.

While this type of board can be thin, it can also be chunky like a brick. Large blocks are still often marketed as vermiculite board. They weigh much less than a block of that size made of concrete or other dense materials. Vermiculite board can come in a variety of colors. The shade will usually range from light and straw-colored to a darker and more reddish brown. Thick vermiculite boards of this type can be used anywhere there is a need for heat resistance, soundproofing or insulation.

There are many other uses for vermiculite besides boards and bricks. It is sometimes put into walls and attics in loose form as insulation. Drywall made from gypsum, also commonly called gypsum board, often contains vermiculite and other heatproof materials. Gypsum is already an insulating and fire-resistant material, so the addition of vermiculite and other substances makes the product even safer. The addition of vermiculite usually also makes the wallboard more soundproof. Gypsum board is the most common drywalling product used today, so many homes contain vermiculite in this form.

Vermiculite has the ability to absorb several times its weight in water which also makes it a popular choice for gardening. Perlite is a natural volcanic glass made mostly of silica that is expanded to make it lightweight and easy to use. It holds its shape better than vermiculite and allows air to flow better through dense soil. A perlite vermiculite combination is sometimes used to aerate and hydrate roots for healthier plants. Vermiculite can be mixed into potting soil or it can be used in hydroponic gardening that grows plants without natural soil of any kind.

Discussion Comments


Why are all vermiculite heat resistant board manufacturers and vendors overseas?


@Nvaradarajan: I think the binder used would typically be a cement, some time of clay or gypsum. Often, several different compounds are used at once. The same binders are usually used when producing products designed for soundproofing.


What is the binder that is used for the manufacture of vermiculite boards for fire resistance applications?

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    • Vermiculite is a natural mineral that must be mined.
      By: praisaeng
      Vermiculite is a natural mineral that must be mined.