If you're planning to renovate your home or office, you'll likely need to work with drywall. Drywall is a popular material used to create walls and ceilings in buildings. It's affordable, easy to install, and provides a smooth surface for painting or wallpapering. However, to achieve a flawless finish, you need to know how to seal drywall properly. In this article, we'll guide you through the process step by step.

What is Drywall?

Drywall, also known as plasterboard or gypsum board, is a building material made of gypsum plaster sandwiched between two sheets of heavy paper. It's used to create interior walls and ceilings, and it's popular because it's relatively easy to install and provides a smooth, even surface for painting or finishing.

Why Do You Need to Seal Drywall?

When you install drywall, there are inevitably gaps between the panels, and these gaps need to be filled to create a smooth, even surface. Additionally, drywall is porous, so it can absorb moisture, which can cause it to deteriorate over time. Sealing drywall helps to prevent moisture from getting in and also makes it easier to paint or wallpaper over.

Materials Needed

Before you get started, you'll need a few materials. Here's what you'll need:

Drywall Joint Compound
Also known as mud or spackle, drywall joint compound is used to fill gaps and smooth out the surface of the drywall.

Drywall Paper Tape
Drywall paper tape is used to reinforce the joints and prevent cracking.

You'll need sandpaper to smooth the surface of the drywall after applying the joint compound.

Putty Knife
A putty knife is used to apply the joint compound and smooth it out.

A paintbrush is used to apply primer and paint to the surface of the drywall.

Vacuum Cleaner
You'll need a vacuum cleaner to clean up the dust created by sanding.

Preparing the Surface

Before you start sealing up the drywall, you need to prepare the surface. Here's what you should do:

Cleaning the Area
Make sure the area is clean and free of debris. Remove any loose or chipped paint, and vacuum up any dust or debris.

Sanding the Surface
Use sandpaper to rough up the surface of the drywall slightly. This will help the joint compound adhere better.

Applying Drywall Joint Compound

Now it's time to start sealing up the drywall. Here's how to do it:

Mixing the Joint Compound
Follow the manufacturer's instructions to mix the joint compound. You'll want it to have the consistency of peanut butter.

Applying the First Layer
Using a putty knife, apply a thin layer of joint compound to the gaps between the drywall panels. Make sure to fill the gaps completely.

Applying the Second Layer
After the first layer has dried (usually about 24 hours), apply a second layer of joint compound. This layer should be slightly wider than the first layer to help feather the edges.

Applying the Final Layer
Oncethe second layer has dried, apply a final layer of joint compound. This layer should be wider than the second layer and should blend in seamlessly with the surrounding drywall surface.

Applying Drywall Tape

Now that the joint compound has been applied, it's time to reinforce the joints with drywall tape. Here's how to do it:

Choosing the Right Tape
There are two types of drywall tape: paper tape and mesh tape. Paper tape is recommended for inside corners, while mesh tape is better for outside corners and flat surfaces.

Measuring and Cutting the Tape
Measure the length of the joint and cut a piece of tape slightly longer than the joint. Then, fold the tape in half lengthwise and crease it down the middle.

Applying the Tape
Using a putty knife, press the tape into the joint, making sure it's fully embedded in the joint compound. Smooth out any wrinkles or bubbles with the putty knife.

Sanding the Surface

After the joint compound and tape have dried (usually about 24 hours), it's time to sand the surface. Here's how to do it:

Sanding after the First Layer
Use fine-grit sandpaper to sand the surface after the first layer of joint compound has dried. Make sure to sand lightly to avoid damaging the surface.

Sanding after the Second Layer
Repeat the sanding process after the second layer of joint compound has dried. This time, use a slightly coarser sandpaper to smooth out any bumps or ridges.

Sanding after the Final Layer
After the final layer of joint compound has dried, sand the surface again, this time using very fine-grit sandpaper. Make sure the surface is smooth and even.

Finishing Touches

Now that the drywall is sealed and sanded, it's time to apply the finishing touches. Here's how to do it:

Applying a Primer
Before you paint or wallpaper the surface, apply a coat of primer. This will help the paint or wallpaper adhere better and will also help to seal the drywall.

Painting the Surface
Once the primer has dried, you can paint the surface. Use a paintbrush or roller to apply the paint, making sure to cover the surface evenly.

Common Mistakes to Avoid

Here are some common mistakes to avoid when sealing up drywall:

Rushing the Process
Take your time and make sure each layer of joint compound and tape is fully dry before moving on to the next layer.

Over-Sanding the Surface
Be careful not to sand too aggressively or you may damage the surface of the drywall.

Not Using Enough Compound or Tape
Make sure to fill the gaps completely with joint compound and use enough tape to reinforce the joints properly.


Sealing up drywall may seem like a daunting task, but with the right materials and techniques, it's actually quite simple. By following the steps outlined in this guide, you can achieve a smooth, even surface that's ready for painting or wallpapering. Just remember to take your time, avoid common mistakes, and have fun!