Drywall mud is used by professionals and do-it-yourselfers alike when hanging drywall. The mud is used to fill in joints, secure and cover drywall tape and to cover up nail and screw heads. There are different grades of drywall mud. Some of it is dries 20 minutes after it is applied, while other types take as long as 24 hours to dry.
Whether you are a professional or an amateur, will be a factor in which type you use. Considering all of the choices, though, there are five basic types of drywall mud, three of which are known as drying types. The fourth type is a light version of each of the previous three. The fifth is known as a setting type of drywall compound.
What You Need to Know
The first four types of drywall mud are called drying-type drywall compound. They come premixed and are ready to use immediately. Whatever is not used can be properly stored and used later.
Taping Compound: When covering up joints and drywall tape with drywall mud, three layers are typically put down. The first two layers use what is called taping compound. Taping compound is used to fill in the joints between drywall sheets and at corners. Anywhere there is a gap between sheets there needs to be tape. Once the taping compound is put down, tape is applied. The excess mud is scraped out and is allowed to dry. A second coat is then applied, which further smooths out the tape. Taping compound does not crack easily and shrinks little.
Topping Compound: After the first two layers have been applied to the drywall, a third, final layer must be put down. This smooths out the last remaining rough spots and can be sanded down. It is on top of this coat that the wall’s texture and paint will be applied. Topping compound is used only to cover up the previous two coats. It is not used to adhere the tape to the joint.
All-Purpose Compound: As an alternative drying type of drywall mud, all purpose compound can be used in lieu of both taping and topping compound. It is the type that is most commonly used because it works for all three layers and can even be used to add texture. The downside is that it is not as strong as the taping/topping layers and is not as crack-resistant. In many cases, it takes 24 hours to fully dry.
LITE Drying Compounds: Each of the previous types has a particular density to it. If it is applied too thickly, it will show through the texture. LITE drying compounds are essentially the same except they go onto the drywall lighter. There is a LITE compound for each of the three types; taping, topping and all purpose.
Setting Compounds: The fifth type of drywall mud is known as setting-type drywall compound. It is most often used by professionals and for patching small holes in the drywall. It is superior to drying compounds in that it dries harder, bonds better, and is more shrink and crack-resistant, but it is harder to use. Plus, it dries a lot faster than drying compounds.
The quickest drying time is about 20 minutes, but there are varieties that take several hours to dry. A second coat can be applied without waiting for the first to dry. That is another advantage of setting type. Setting type does not come premixed, so it must be taken to the right consistency before it can be used.
Different kinds of drywall mud are used for various jobs, although many of the differences allow the drywaller to choose the type to be used. The five basic types of drywall compound discussed in this article are used in both professional and private applications.