How to Apply Vermiculite & Cement

Apply vermiculite and cement in a mold to set for use.

Vermiculite is a mineral mined in the U.S. and around the world, used for insulation and lightweight structures. Found in nature, vermiculite is a flake-like yellow or brown mineral. When the mineral is processed for use in construction, it becomes an expandable substance. When combined with cement, the vermiculite creates a sturdy structural material that dries strongly and holds a shape. Fortunately, applying the cement/vermiculite mixture isn't a special process.

Things You'll Need

• Vermiculite
• Cement
• Water
• Tarp or another barrier
• Cement mold
• Trowel

Instructions

1. Prepare your vermiculite, water and cement for mixing. The mixture is six parts vermiculite to one part cement. Dineen Sales Limited, a dealer in construction materials, suggests having enough water nearby to make the mix into a loose paste. The amount will vary.

2. Mix the vermiculite, water and cement in a cement mixer to create a slurry. Let the cement mixer work until the slurry forms, adding water in small increments to avoid making the mixture too watery.

3. Place the cement molds on a tarp, plyboard or another barrier between the molds and the ground to prevent splashing the mix onto the ground. Pour the vermiculite and cement mixture into the molds to set into the desired shape.

4. Scrape away the excess mix from the top of the mold with the trowel. Do this to ensure that the final product has nice flat sides and so that the mold releases easily once the mixture sets.

5. Let the mixture dry in the mold 24 hours before attempting removal. Test one vermiculite/cement block. If it breaks or seems wet as the mold is removed, do not attempt to remove the others.

Tips & Warnings

• The vermiculite blocks are lighter and more prone to breaking than 100 percent cement blocks. So, use care in extracting the blocks from the molds to avoid breakage.

• The cement in the mix is a caustic substance. When handling the cement, wear goggles, long pants, boots, gloves and a face mask to prevent inhalation and from getting wet cement on your skin.

References

• Ohio Concrete; Floating Concrete Lesson
• The Vermiculite Insititute; Vermiculite
• Dineen Sales; Lightweight Concrete
• William Sinclair; Insulating Concrete Roof and Floor Screeds Using Vermiculite