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What is Drywall Typically Made Of?

After the issue of cheap Chinese-made drywall came to light, most homeowners were left asking the question on what their drywall and joint compound was made of. In addition to finding the most reputable drywall supplier Toronto, it is imperative that you also learn of the key components that make a good quality drywall.

Rock and paper

Even after years of technological advancements, the best drywalls are made using simple materials: rock and paper. While each manufacturer uses various additives, the main materials in quality drywall are:


This material has for years been the backbone of drywall products and today makes up between 70 and 90 percent of the drywall sheet. Gypsum is easy to mine; it is fire-proof and offers remarkable soundproofing benefits. The fire-rated Type X drywall has fiberglass added to gypsum. What is more, is that gypsum dust doesn’t cause grave health issues.


This material makes up the remaining 10% of the drywall composition. It is the paper facing on either side of the drywall. There has been an increase in the use of mold-resistant fiberglass mat facing on drywall today.

Gypsum and cellulose are the main materials that makeup drywall. Other materials found in trace amounts include:

  • Starch
  • Crystalline silica
  • Mica
  • Potassium sulfate
  • Vermiculite
  • Boric acid
  • Wax

Joint Compound Composition

Mud or joint compound looks like gypsum but it is not gypsum. This is the material used to cover the tape joints between drywall sheets.

The joint compound is made of:

Calcium carbonate

This material is also referred to as ground limestone. It is the main mineral that creates the joint compound.


This is ultra-fine material similar to baby powder. It is used in the joint compound since its particles lie flat and are resistant to cracking. This is the material that helps the mud sand down as smooth as glass. Joint compound is made of 5 to 15 percent of Talcum.

Sulfur and strontium are bad

The Chinese drywall contained sulfur. All the U.S. made drywall don’t have sulfur. It is also good to note that the Chinese made drywalls also contained a significantly high concentration of Strontium. These are important points to put in mind when searching for drywall from the local drywall supplier Toronto.

In both U.S. and Chinese drywall, both formaldehyde and acetaldehyde were found. The elements were within the safe limits in the U.S. manufactured drywall.

The most popular drywall is the Sheetrock brand wallboard which is manufactured by the USG Corporation. What this means is that if your wallboard is from USG you can be assured of the best quality. With 90 years of manufacturing, USG Corporation reports that its products have never had the same issues as the Chinese drywall. USG also stated that their products are manufactured in North America and have never been manufactured in China. A joint study by the U.S. Consumer Product Safety Commission and other federal agencies reported that the U.S. made drywall has no issues that are similar to those of drywall manufactured in China.