What USG Joint Compound Should I Buy for My Project? (All-purpose, Plus 3 or Topping)

If you’re tackling a drywall project, choosing the right joint compound—or drywall mud—is one of the most important decisions you’ll make. Three of the most commonly used products are All-Purpose Joint Compound, Plus 3 Lightweight All-Purpose Compound, and Topping Compound. While they’re often sold side-by-side in hardware stores, they serve different purposes and perform best in specific stages of the drywall finishing process. Understanding their differences can help you work more efficiently and achieve a better final result.

All-Purpose Joint Compound

All-Purpose Joint Compound is the standard, workhorse product for drywall finishing. It’s thick, strong, and designed to do it all—embedding joint tape, filling seams, and finishing coats. Many professionals use it as their base layer because it adheres well and forms a solid, crack-resistant finish. It also contains more glue than other typed of joint compound, which is great for making sure you tape stays embedded. However, it’s heavier than other options and can be more tiring to work with, especially on ceilings or large surfaces. It also dries more slowly and typically requires more sanding, making it less ideal for those seeking a quicker, cleaner finish.

Plus 3 Joint Compound

Plus 3 Lightweight All-Purpose Compound is a variation of standard all-purpose mud, designed to be approximately 30 percent lighter. It handles much more easily and sands with less effort, which makes it a favorite among DIYers and professionals who want to reduce fatigue on larger jobs. It still performs well for embedding tape and applying finish coats, though it may not be quite as strong as regular all-purpose mud in terms of bonding power. Because it shrinks less and sands more smoothly, it’s often used for second and third coats to achieve a clean surface before painting.

Topping Compound

Topping Compound, unlike the other two, is meant exclusively for the final coats of a drywall job. It isn’t designed for embedding tape or covering large gaps; instead, it’s used after the seams are already filled and reinforced. Its smooth, creamy texture makes it very easy to feather out over joints and creates an exceptionally smooth finish with minimal shrinkage. Topping mud also sands with ease, which is why many pros rely on it for the final coat to create a nearly flawless surface. However, because it’s softer and less adhesive, it should never be used as a first or only coat.

In practical terms, many experienced drywallers use a combination of these compounds. A typical approach would involve starting with all-purpose for embedding tape and applying initial coats, then switching to Plus 3 or topping compound for the final coat or two. This strategy takes advantage of the bonding strength of all-purpose compounds and the finish quality of topping mud.

Choosing between all-purpose, Plus 3, and topping compounds really comes down to your goals and experience level. If you’re doing a full drywall installation and want one reliable product, all-purpose mud is a solid choice. If ease of use and sanding is your priority—especially if you’re working alone or overhead—Plus 3 offers excellent handling with minimal sacrifice in performance. And if you’re focused on achieving the smoothest finish possible with the least amount of sanding effort, topping compound is the clear winner for the final coat.

Ultimately, using the right mud at each stage of your drywall project will save time, reduce frustration, and leave you with a professional-looking result.