What Is Drywall Made of? 

Which Mineral Is a Major Component of Drywall?

As we’ve just learned, one of the primary drywall ingredients is gypsum rock. Gypsum, or dihydrous calcium sulphate, is a mineral that has been used in construction for centuries. The reason for its popularity in the industry is that it is fireproof and easy to mine. It can also help to reduce sound travel and doesn’t pose any major health concerns.

Drywall panels comprise 90 percent gypsum rock.

To create gypsum board, the mineral is first ground to create gypsum powder, which is then blended with a variety of additives, such as wax, vermiculite, starch, plasticizers, boric acid, potassium sulphate, ground mica crystals, and more. These substances are often found in trace amounts.

At this point, the gypsum is in a paste form. It is then sandwiched between cellulose or fibreglass (which we will get to in a minute), left to harden in a drying room, and then used as the foundation in drywall structures.

About the Cellulose or Fibreglass Outer Coating

In addition to gypsum, drywall sheets are made up of 10 percent cellulose. This is the “paper” you see on the outside of each sheet. It is added to improve the overall strength and resilience of drywall panels and also offers great fire resistance.

This material is also added to boost the moisture and impact resistance of the gypsum board and can help to reduce the expansion and shrinkage of the building material. 

In many cases today, drywall is coated with fiberglass mats that are mold-resistant rather than paper. If you've ever used fiberglass joint tape, you're essentially applying the same kind of stuff that's used in mold-resistant plasterboard sheets.

What Is Drywall Mud Made of? 

Drywall construction doesn’t stop at the wallboards. After these boards are hung, they are covered with a layer of joint compound in a process called “mudding.” The point of this is to strengthen the wall and hide any bumps or empty spaces to create a consistent, smooth surface. 

The common misconception is that compound for drywall is just gypsum plaster. This simply isn’t the case. When creating drywall mud or joint compound for drywall, there are two main substances that are used. Let’s take a closer look at each of them in the section below.

Calcium Carbonate (Ground Limestone) 

Unlike gypsum paste, whose main mineral is gypsum rock, joint compound’s main mineral comes from limestone. Calcium carbonate is an essential component of drywall mud. It is a cost-effective filler and a thickening agent to give the joint compound its paste-like appearance.

Talcum Powder or Talc

It also contains another mineral known as talcum, or talc for short. This baby powder-like ultra-fine material is utilized in drywall mud because its particles lay flat and don't shatter easily. Your mud will become as smooth as glass with the help of the mineral talc. Talc makes up between 5 and 15 percent of the total volume of traditional joint compound.

Water Is Then Added to Finish It Off

Both calcium carbonate and talcum are in powder form, so how does it become a paste?

Well, to create the drywall mud we know and love, a combination of these minerals is added to water that, when left to dry, will harden. Joint compound and gypsum plaster can also be used for creating ceiling and wall texture. They hold their shape well and can be molded to form a variety of patterns and shapes to add aesthetic appeal.

Want to Know More About Gypsum Wallboard and Plaster? Contact Us Today!

Now that you have the answer to the question, “What is drywall made out of?” you won’t be left wondering the next time you look at your walls and ceilings. It’s important to keep in mind that drywall composition often varies from one brand of material to the next, but the basic concept and primary constituents remain the same. 

If you have more questions about drywall cement or plasterboard, you can contact Innovation Drywall of Edmonton for assistance. Call us today or fill out the contact form to hear back from us.