Joint Compound (Drywall Mud) vs Spackle [Differences]

You’ve probably used spackle before, to plug holes in your drywall. But did you know that spackle is actually very different than drywall mud\joint compound?

Both are whitish-grayish pastes used on drywall. Both are similar in their makeup, consistency, and look.

They couldn’t be that different, right?

Interestingly enough, that’s pretty much where the similarities end.

Joint Compound and Spackle actually have rather different uses. If you want the quick and dirty answer as to whether you should use spackle vs joint compound, it comes down to this:

  • Joint compound (drywall mud) is used when initially installing drywall. 
  • Spackle is used to fix minor blemishes, cracks, and other small repairs. 

This is the deciding factor when choosing one over the other.

Choosing the right one will make your job easier and more efficient, while using the wrong one can lead to poor results. Worse yet, it might require you to do the project all over again.

Deciding between spackle vs joint compound is a vital distinction for a successful project. In this article, we’ll dive into each in more depth, so that you can use the right tool for the job.

What Is Joint Compound (Drywall Mud)?

Joint compound, or drywall mud, is a thick, substance designed to smooth-out the gaps between drywall panels, corners, and edges. It’s sometimes called drywall mud because it has a consistency similar to mud. 

Joint compound is made up of several different components, depending on the specific type of joint compound.

The bulk of it primarily consists of limestone and gypsum dust that you mix together with water. Other components include clay, starch, expanded perlite, mica, ethylene-vinyl acetate polymer, attapulgite, and other ingredients. 

Joint compound is applied in several layers, to get a progressively smooth finish to your walls.

Drywall mud comes in 1-quart to 5-gallon containers, or you can buy it in a powdered form. You can then mix the powder with water just before use to create the paste. It’s often sold in large containers for use on larger projects.

You’ll use a lot of it when installing drywall, unlike small, quick, one-off projects where something like spackle would be more appropriate.

Drywall mud takes about 24 hours before you can sand it down or paint it. 

There are multiple different types of joint compound:

  • All-Purpose Joint Compound: As its name implies, all-purpose joint compound is effective for doing any joint compound work. That said, it does have its limitations. It tends to shrink more, and it’s harder to sand. 
  • Setting Type Joint Compound: Setting type joint compound, or hot mud, uses a chemical reaction to heat up when you mix it. It has a lower set and dry time than all-purpose joint compound.
  • Drying Type Joint Compound: This type of drywall mud comes mixed and ready to use, but it generally takes longer to air dry. 
  • Special Joint Compounds: These drywall muds match well with certain types of drywall, such as low-dust and fireproof drywall. Manufacturers specifically formulate some joint compounds to resist mold. 

What Is Spackle?

Spackle is also a paste used to fill in gaps in walls., but it’s better suited for smaller jobs.

Spackle has a thinner consistency than joint compound. Think of it more like toothpaste than mud. It’s made up primarily of gypsum powders, and binders.

Contractors use spackle to fill small holes and cracks in walls and ceilings. It’s designed to fill small gaps and cracks, rather than using it when initially installing drywall over large areas,

For example, if you damage your wall, or need to fill a hole, you’ll use spackle to fill it in. Spackle is great to fill in something as small as a nail hole.

Spackle dries much faster than joint compound, which is part of the reason why spackle is better for repairing minor damage to walls.

Because it’s used on a smaller scale, spackle comes in smaller containers. That makes it more economical option than joint compound, when it’s for the proper purposes. 

Not unlike joint compound, spackle is also available in several different forms, including:

  • Standard spackle: Standard spackle is an effective general-use spackle when you need to patch holes here and there. It dries quickly and is easy to sand. 
  • Lightweight spackle: Lightweight spackle is the least durable. That makes it better suited to small jobs in hard-to-reach areas, where it’s less likely to be touched or bumped. 
  • Acrylic spackle: Contractors use acrylic spackle for filling small holes like any other type of spackle but can also be used on brick and stone. It doesn’t shrink much.
  • Epoxy spackle: Has to be mixed but holds its shape well and can be sanded down easily.
  • Vinyl spackle: This is a water-based spackle, and contractors use it for filling in small holes and scratches. 
  • Powder spackle: Like joint compound, spackle can come pre-mixed or in powder form that you mix yourself just before applying. 

Joint Compound vs. Spackle: Differences

The main reason joint compound and spackle are different is their ingredients. It’s worth noting, though, that they do have some overlapping components. 

The main ingredient in spackle is gypsum. Gypsum is a white/gray mineral also known as hydrated calcium sulfate.

You’ll also find gypsum in plaster of Paris, cement, and fertilizers. Gypsum is not remarkably durable on its own, but it is when you mix it with adhesives. 

On the other hand, joint compound has more of a limestone base.

Limestone is a sedimentary rock consisting of the minerals aragonite and calcite. Limestone is an ingredient in chalk. It’s used extensively in concrete roads and buildings. Limestone is a key ingredient of joint compound because of its strength, making for durable surfaces once sanding is complete. 

A significant difference between spackle vs joint compound is their intended purpose. Joint compound is designed to fill in gaps between drywall panels. As such, it’s an integral part of the process when it comes to installing walls. 

Builders don’t use spackle for initial construction, but instead for repairs.

For example, you can use spackle for repairing small holes or dents in walls. It can come in handy for renters, as you can use it to seal nail holes and other small holes that can affect how much you get back of your deposit. 

The last thing to note is their price.

If you go by the price you pay by weight, joint compound is less expensive. However, you have to buy more to complete the jobs that you use joint compound for, so it ends up being more expensive.

On the other hand, spackle is more costly by weight, but you’ll spend less considering its intended uses.

When to Use Joint Compound vs. Spackle

If you’re wondering when to use spackle vs joint compound, joint compound is for sealing new drywall installations. So, if you’re building a new home or office, you would use joint compound to finish off any seams. You would also use joint compound if you were doing a complete remodel that requires tearing down existing walls. 

On the other hand, spackle is what you’ll want to use for smaller jobs. For example, use spackle if you need to repair any damage such as holes, dents, or even something as small as nail holes. 

Worth noting is that if you have minor wall damage in need of repair, you can use joint compound to fill it.

However, if you just installed a bunch of drywall, you can’t use spackle to fill in the gaps. The reason being is that spackle isn’t for covering large areas because it will likely crack, crumble, or shrink.

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Tim Wells

Tim Wells, the founder of Garage Transformed, has been featured in dozens of home renovation publications, including, Home Stratosphere, House Digest, Livingetc, and SFGate. Since 2018, he has helped over two million people transform their everyday garages into something they can be proud of. He lives in Central Florida with his wife and bulldog.