Joint Compound vs Plaster: Pick the Right Material

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Do you badly need a wall repair or hole patching? Before rushing to the nearest home improvement store, get your facts right. There will be a lot of wall repairing choices on the shelves; all will advertise to get the basic works done. So, how can you know which one is best for your job?

Before jumping on to your next project, know the difference between joint compound vs plaster. Look no further to buy the right product and do your home renovating job like a pro!

Scroll down to clear your concept on joint compound vs plaster of Paris, which suits better for what type of work. On top of that, we will share some useful tips on mixing plaster of Paris with joint compound.

Plaster vs Joint Compound: A Details Comparison Overview

Before getting on to an in-depth detailed explanation, here’s a concise and brief comparison chart. To weight out their differences, we’ve considered the following factors:

  • Consistency
  • Setting Time
  • Required Effort
  • Shrinkage
  • Proneness to Crack
  • Water Solubility
  • Flammable
  • Life Expectancy
  • Quality
  • Sanding Tendency
  • Skill requirement

So, get a quick glance to easily understand the dissimilarities between the patching plaster vs joint compound.

Factor Considered Joint CompoundPlaster
ConsistencyThinnerThicker
Drying TimeMoreLess
Amount of Effort Required to Sand LessMore
Required EffortTakes less laborLabor-intensive
ShrinkageShrinks moreDoesn’t shrink
Prone to crackingEasily CracksDoesn’t crack
Water ResistanceNoYes
Fire RatingNoYes
DurabilityLessMore
QualityHighRelatively low
Skill RequiredLowHigh

Which One Has More Consistency?

Consistency is one of the most significant factors that set the two categories worlds apart. The joint compound, widely known as dry mud, is a gypsum-based white mixture. It has the consistency of cake frosting. On the other hand, plaster is a soft mixture of lime and water, which is way thicker in consistency than dry mud.

So, use dry mud only when the gaps are 1/8” or less. Repairing plaster walls with joint compound gives a seamless finish as it allows to apply a thinner coat.

Which Takes More Time To Set?

Settling time of both of the kind are also poles apart. So if you are a newbie in taping drywall seams, go for the joint compound to level up your game. It gives you the flexibility to go through the trial and error process when you make a mistake or want a better finishing.

After applying a coat, it takes 24 hours to dry. So you can take your time while working with it—no need to race against the clock.

In contrast, plaster sets in real quick, like 30 to 45 minutes. So you have to be fast to work with it. Also, there’s no room for error. So some professional skill is required during plastering.

Which Sands More Easily?

To get rid of the imperfection and achieve a smoother finish sanding is needed. With dry mud, it’s super effortless as it sands a LOT more. Whereas, plaster doesn’t sand that much, and sanding it is a labor-intensive work to do.

So, here’s another reason for the untrained to not use plaster. You can’t effectively smooth away bad plaster without messing up with the quality of the finished product. So, you must get it right on the first go.

Which Shrinks And Cracks More?

One of the disadvantages of all purpose joint compound is that it shows more shrinking and cracking after it dries. So you need to apply extra coats to fill the large holes and gaps.

On the contrary, plaster of Paris doesn’t shrink while setting. Therefore it can be a brilliant medium for casting mold. It’s also less prone to cracking. So, you can apply it as the first coat and then use joint compound as the topping. Doing this will able you to sand away more efficiently and give a seamless finish.

Which One Is More Soluble In Water?

Obviously, it’s the premix joint compound. Water solubility is both an advantage and disadvantage of the dry mud. The pros of being reactivated after water application, you can water trowel it if you make a mistake.

Once it sets, you can take the ridges out. Or you can move the piece of tape that didn’t lay flat like you wanted it to. Again, the downside is it’s water-soluble, so you may not use it in area where there’s a lot of humidity or moisture.

Here comes the setting type joint compound to the rescue that is a bit more moisture resistant. So, if you’re going to tape a bathroom, this is the product that you want to use.

On the other hand, plaster doesn’t retain water; it shows super resistance to it. So, use it in a humid area to get the best outcome.

So, setting type joint compound vs plaster, which has better water resistance? No brainer, it’s the plaster.

Which One Gives Better Protection Against Fire?

Well, both of them are non-flammable. But the plaster offers better protection against fire. It’s an excellent heat-insulating and fire-resistant material. So, if you want to make your room safe against the fire, go for the plaster of Paris. But do keep in mind, it decomposes at extremely high temperature and creates toxic oxides of sulfur.

So, gypsum plaster vs joint compound, which one has the better fire rating? Our vote goes to the gypsum plaster.

Which One Has Longevity?

Plaster has been used since the time of ancient Egypt for wall finishing. In fact, the tombs of the Pharaohs, which are still standing today features the plaster walls. There’s no doubt that you can measure its lifetime in centuries. On the other side, dry mud is less durable; its life span is measured in decades.

So if you want to build a home that lasts for generations go for the plaster instead of the dry wall. Do you have sporty kids who love to throw footballs or soccer balls at the wall? You may want to have plastering finished wall that can withstand anything your kid throws at.

Which One Offers To Provide Better Quality?

Plaster provides undoubtedly top-notch quality than dry mud. It gives high-quality, smooth finishing, which can be the flawless backdrop for your interior decoration. Again, the material takes paint really well and makes the room look more vibrant after painting. On top of that, it’s thicker and less porous, which prevents sound from traveling effortlessly. Therefore, it gives better sound-proof quality and brings a peacefully wholesome environment in your home.

Do you have a noisy kid? Or have you got a better half who loves to watch television at a high volume? Use plaster in the walls and sleep better, forgetting the disturbance.

Applications of Spackle vs Joint Compound vs Plaster

To decide which one to use, you need to consider the application because all of the categories differ in consistency and drying time.

Taping Drywall Seams

If you’re looking for the best product to tape your drywall seams with then, you’re most likely looking for the dry mud. They have longer working time, which makes it ideal if you’re new at this. Also, you can apply thinner coat with them and sand them easily.

There are different types of joint compound to work with. But the ready mixed all purpose one saves you the most, just add water, and you’re good to go.

Repair Work

Sometimes instead of entirely taping the drywall, you need to do some repairing or patch a hole. In most cases, plaster is going to be the best solution for visible defects on the drywalls. As it’s thicker in consistency and less likely to shrink and crack, it can fill out any dents and dings. So patch holes that are larger than 1/8” using it.

If you need a resurfacing on an old wall with wear and tear, go for the plaster. It takes a lot more labor to sand and smooth, but worth applying before a fresh coat of paint.

Filling Small Holes of Nails

Sometimes instead of large gaps, you’ll need to fill out small screw holes. Spackle is designed to fill cavities that are less than 4 inches or 10 cm. But if the gap is larger, you’ll need to use mesh or wire to form firm support. It’s shrink-free and dries rapidly. Besides, you don’t need to prime before repairing unless you’re spackling the exterior area.

Texturize Walls and Ceilings

Do you love to have a new look for your walls and ceilings? Decide the type of texture you would like to have. Surfaces like popcorn ceilings or knockdown textures are perfect for shaping with dry mud. Sorry to burst your bubble, but the hype for them is decreasing nowadays. People are opting for a customized texture with an exceptional finish. Here comes the plaster offering a wide-ranging variety of styles to pick from. With a sponge or trowel, texturize exactly how you desire. But make sure to do it swiftly, as it dries fast.

Mixing the Two to Get the Best out of Them

Do you want something that dries faster and sands easily? Well, mix them both! From patching to skimming, it always serves the purpose. Follow the steps given below to get the most out of them both:

  1. Take some joint compound to make a little mud donut by twirling the knife around the center.
  2. Pour some water first in the hole of the donut.
  3. Add plaster in it. Mix the water and the plaster.
  4. After the plaster has absorbed all the water, start mixing the donut thoroughly too, with a trowel.

Ta-da you’ve made yourself a DIY quick-set! If this mixture is wet for you, try to mix in a 60/40 ratio of dry mud and plaster.

Frequently Asked Questions (FAQs)

Can you use joint compound over plaster?

A: Sure. It’s easy to sand, can be applied in a thinner coat, and adheres well to most surfaces. So lay it as a topping on plaster walls to give a perfect, smooth, and seamless finish.

Can I skim coat plaster with joint compound?

A: Yes, we can’t see any reason not to. Skim coat plaster with joint compound and smooth out the surface with the help of a trowel. You can apply multiple coats with as less sanding as possible until the dings and cracks smooth out.

What is the difference between joint compound and plaster?

A: The joint compound has lesser consistency, more water-soluble, and prone to shrinking and cracking. In contrast, plaster is thicker, water and fire-resistant, and shrink-free. Also, it has fewer pores, which makes paint sit well and makes the room better sound-proof.

The Bottom Line

Now that you’ve got to know the difference between the joint compound vs plaster, consider the type of restoration you need to do. So, no more confused roaming in the aisle, pick the right material and get to the work. Happy renovating!