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The Most Common Drywall Finishing Mistakes and How to Fix Them

The Most Common Drywall Finishing Mistakes and How to Fix Them

The Most Common Drywall Finishing Mistakes and How to Fix Them

Drywall finishing is a crucial step in the construction and remodeling process, as it can significantly impact the overall appearance and quality of your walls. However, even the most experienced DIYers and professionals can make mistakes during this process. In this article, we'll go over some of the most common drywall finishing mistakes and show you how to fix them step by step. You can achieve a smooth and professional-looking finish on your walls by following these tips.

Common Drywall Finishing Mistakes

Over-sanding the drywall

Over-sanding the surface is one of the most common mistakes people make when finishing drywall. Over-sanding can cause the paper facing to fray or tear, resulting in an uneven finish and potential drywall damage. Over-sanding includes sanding too much or applying too much force when you are sanding. 

Inadequate joint compound application

Another common blunder is using too little or too much joint compound. Uneven application can cause visible seams, cracks, or bulging joints, compromising the overall appearance of your walls.

Not using the right tools

Using the wrong tools for the job can also cause issues during the drywall finishing process. Here are two common tool-related mistakes when finishing drywall:

Using the wrong taping knife size

The size of the taping knife is essential when it comes to achieving a smooth finish. A smaller knife may not cover the joint adequately, while a larger one can make it difficult to control the application.

Using rusted or damaged drywall knives

Using rusted or damaged drywall knives can lead to uneven application of joint compound and can affect the overall result of the project. Damaged knives can cause the joint compound to be applied inconsistently, making it difficult to achieve a smooth, seamless finish.

Poorly installed corner beads

Corner beads are necessary for creating sharp, clean corners. However, if installed incorrectly, they can cause visible flaws such as crooked or misaligned corners.

Forgetting to feather out joints

Proper feathering of joints is essential for achieving a seamless and professional finish. Neglecting this step can result in visible seams and an uneven appearance.

How to Fix and Prevent Drywall Finishing Mistakes

Fixing over-sanded drywall

Begin by applying a thin layer of joint compound over the damaged area to repair over-sanded drywall. Allow it to dry before lightly sanding the surface to make it smooth and even. If necessary, repeat this procedure.

To gently smooth out the joint compound, use a sanding block or pole sander with fine-grit sandpaper. Over-sanding the surface can cause damage to the drywall paper facing.

Lightly apply pressure when using a pole sander as to not damage the drywall. Make sure to wear proper protective equipment to prevent inhalation of sanded particles. 

Correcting inadequate joint compound application

If you've applied too little joint compound, simply add more and smooth it out using a taping knife. If you've applied too much, wait for the compound to dry, then sand down the excess until the surface is smooth and even.

When applying joint compound, spread a thin, even layer with a taping knife. Make sure to feather the edges to ensure that the compound blends in with the surrounding drywall.

Choosing the right tools

Using the correct taping knife size

Choose a taping knife that fits the size of the joint you're working on. A 6-inch joint knife is ideal for embedding tape and applying first coats, while a 10- or 12-inch knife is ideal for feathering and finishing coats.

Using well-maintained drywall knives and mud pans

Before beginning your project, inspect your tools to avoid problems caused by rusted or damaged drywall knives. To avoid rust and damage, clean and maintain your drywall knives on a regular basis. If you discover that your knives are rusted or damaged, replace the drywall knives before continuing with your project.

Cleaning your drywall tools

Repairing poorly installed corner beads

To fix misaligned corner beads, carefully remove the existing bead and any damaged drywall. Install a new corner bead, ensuring it is aligned correctly and securely fastened. Apply joint compound to the corner, feathering it out on both sides. Allow it to dry, then sand it smooth.

Take your time when installing corner beads, ensuring they are properly aligned and secure. Before securing the bead, use a level or straight edge to ensure proper alignment.

Fixing unfeathered joints

If you've forgotten to feather out your joints, carefully sand the edges of the joint compound to create a smooth transition between the joint and the surrounding drywall. Apply additional joint compound if necessary, and feather it out to blend seamlessly with the existing surface.

Always remember to feather out your joints when finishing drywall. This will help create a seamless, professional appearance and eliminate visible seams.


  1. What type of joint compound should I use to finish my drywall? There are several types of joint compound available, including all-purpose, lightweight, and setting-type compounds. For most projects, an all-purpose joint compound is a good choice, as it can be used for both taping and finishing


  2. How many coats of joint compound should I apply? Typically, three coats of joint compound are recommended for a smooth, professional finish. The first coat is used for taping, the second for filling and smoothing, and the third for final finishing.

  3. What grit sandpaper should I use for sanding drywall? A fine-grit sandpaper, such as 120 or 150 grit, is ideal for sanding drywall. This will help prevent over-sanding and damage to the paper facing.

  4. How long should I wait between coats of joint compound? Allow the joint compound to dry completely between coats, which usually takes around 24 hours. Drying times can vary depending on humidity and temperature, so be sure to check the manufacturer's recommendations.

  5. What is the best way to ensure straight, clean corners? Using properly installed corner beads will help you achieve straight, clean corners. Be sure to align the beads correctly and secure them in place before applying joint compound.


Drywall finishing may seem daunting, but by avoiding these common mistakes and following the suggested solutions, you can achieve a professional and smooth finish on your walls. Take the time to prepare your surfaces, use the right tools and techniques, and be patient throughout the process. With practice, you will become more proficient in drywall finishing and be proud of the results you achieve and at Timothy's Toolbox we are here to help in your next drywall project.

Previous article Tips To Successfully Mud and Tape Drywall Corners


Abigail Burton - March 11, 2024

What if over sanded drywall was then painted?

The wall was built from new. The over sanding occurred while trying to smooth the joins. However it wasn’t noticed until after the painting was complete.

So the oversanded plaster now has undercoat and two coats of wall paint on it.

What do you think can be done?

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