How to Smooth Walls

Have you ever wanted a smooth wall in your home? I have! Especially as prep before I wallpaper- there’s nothing worse than drywall texture showing through paper. It’s also a nice look to have a smooth wall before painting. I’m going to show you how to smooth walls by doing a skim coat. This post will have DIY tips and include a video and lots of picture so you can do it too!

For this project, I’m working on my craft room. Last week I wallpapered one side of the room. The slanted walls really showed the drywall texture through the wallpaper. Which I HATE! Before I did the other side (which has worse texture), I thought it’d be good to try doing a skim coat. Spoiler alert- it worked so well! Ready to see how?!

Do all textured walls need to be smoothed before wallpaper?

If you are doing this project before wallpapering, I’m going to suggest that you look over my tutorial about if you can wallpaper over textured walls. Because MOST of the time the answer is YES! So you can usually skip this tedious skim coat step.

However, if you’ve bought wallpaper and tried it on your wall and the texture shows through or you want a smooth wall before painting. This post is for you!

Can you Wallpaper over Textured Walls?

how to smooth walls

Let’s start with the video tutorial so you get an overview on how to smooth walls. Plus I show you a video of the craft room with the finished wallpaper! Then, I’ll dive in with more details below:

If the video doesn’t work here, you can watch it on YouTube here. I’d be over the moon happy if you subscribed to my YouTube channel! Videos are actually released on YouTube first (usually the night before they’re published on the blog). Thank you!

SUPPLIES

9″ Paint Roller Frame
Paint Roller Cover with 3/4″ Nap
Paint Brush Extension Pole
Topping Joint Compound (we used 1 – 1/2 of the 4.5 gallon buckets)
14″ Taping Knife
14″ Drywall Mud Pan
Drill
Mixing Paddle for a Drill
Joint Knife
LED Work Light
Fine Drywall Sanding Block
5-gallon bucket
Sponge
Drywall Primer

For this project, we bought a 14″ taping knife and two buckets of joint compound. That cost $50. So this isn’t an expensive project cost wise (especially if you mostly have the tools and supplies like we do), but it is labor intensive. So if a contractor was charging for this, most of the cost would be in the labor because it takes time and is tedious.

Note, for this project I suggest investing in a longer taping knife. We bought a 14″ long taping knife even though we already owned a shorter one. Why? Because the longer the blade, the flatter the finish will be. Another option is using a long skimming blade. They come in lengths up to 40″ to get a really even finish.

what is skim coating?

So, what is skim coating? Skim coating is where you take drywall mud and put a thin layer on top of the walls texture to get a smooth surface. This method can be used to repair drywall that is damaged or just smooth out textured walls.

This is the method we’ll be using to smooth the walls to prep for wallpaper. This can be also be done before painting or creating an accent wall and is a great way to give the walls a like-new appearance.

before

First off, here’s the texture on the wall in my craft room-

It doesn’t look bad from far away, but close up it’s terrible.

So that was my starting point! Really rough texture that I hated.

step 1- scrape the existing texture

To start, scrape the existing texture with the taping knife. If there’s high ridges in the drywall, this will cut them off and jump start the process for getting a smooth wall. It will also save time later when applying the skim coat since less layers will be needed.

step 2- prepare the joint compound

For this project we’re using a product called Topping that comes pre-mixed in a bucket. It’s designed as a finishing joint compound that creates a smooth finish and is easy to sand. Not having to mix the joint compound saves a step and makes this project less messy and easier. Note- the dry mix is cheaper if you’d like to save some money on this project.

Next, prepare the joint compound to get the right consistency before applying it to the wall. We will thin the joint compound a bit to make it easier to spread on the wall and get smooth.

First, add a little water to the bucket of joint compound. Then, use a mixing attachment on a drill to stir it. Keep adding water until it’s about the consistency of thick cake icing. We probably only added about 1 cup of water total.

Make sure to not make it too thin! It should hold its shape and not drip off the mixer. Adding too much water will make for a messy application and can result in air holes in the mud that will dry and create pin holes in the finish.

step 3- paint the joint compound on the wall

And now, the easiest way to apply the joint compound to the wall is to paint it on with a roller. This is the main way to make this a DIY project! Sure you could use a knife and use that to put the joint compound on the wall, but that is a much slower and trickier process (especially if you don’t do it often).

Place a roller cover onto a 9″ roller frame. The roller cover can be old and used- that’s totally fine. It should have a 3/4″ nap so that it’ll apply the joint compound in a thick layer and work it into the existing drywall texture as it does. Last, attach a paint brush extension pole to the roller frame so all parts of the wall can be easily reached without a ladder or stool.

Dip the roller right into the bucket that the joint compound comes in. Rotate which section of the roller is being dipped into the bucket so all of the roller gets covered in joint compound.

Next, roll the the joint compound onto the wall. Start in the middle of the wall and then push the roller to the top and then to the bottom. It will be most thick in the middle since that’s where the joint compound was first applied. Roll it all the way up and down to distribute it evenly. Don’t worry if it’s not perfect- the next step will clean it up nicely.

Work in small sections on the wall– we generally did 4’x4′ sections at a time since we were either rolling on the angled wall or the flat part of the wall. If your whole wall is flat, you can work in up to 4’x8′ sections. Go as far as possible without the mud drying out.

Note, the working time on the joint compound can be affected by room temperature, airflow, and humidity. So, each space will be different.

Pressing the roller onto the wall firmly will remove any air that might be in the mud that could cause bubbles (another great reason to “paint” it on).

While painting on the joint compound, stay an inch away from the baseboards, other walls, outlets and the ceiling. Work as far as possible without the mud drying.

Another tip, keep a bucket of water and a sponge handy. That way it’s easy to clean up if any joint compound is flipped on the floor or anywhere it isn’t wanted.

step 4- remove excess joint compound and smooth it out

Next, use the 14-inch taping knife to skim off the drywall compound. Make sure to examine the knife before beginning and see how the blade curves. Position the knife so the curve is away from the wall to make sure it doesn’t gouge the wall.

Scrape from the top and pull the knife downwards. This will put some mud on the knife, use that in the inch on the top and sides where the joint compound wasn’t spread in the last step. Work down the wall until you’re 80% of the way down. Then go down to the bottom and do the same going up.

Continue in column sections across the wall. Don’t push so hard to take all of the mud off. Just flatten the joint compound. Put any excess mud in the pan. You can scrape the excess mud back into the bucket if it’s clean.

Don’t be too much of a perfectionist– especially on the first pass through. The main goal is to remove the excess joint compound while it’s still wet. The idea is to to apply a few thin coats to build up a smooth wall.

Once the first section is smoothed out, go back to step 3 and continue to paint on the joint compound. Overlap the last section by a few inches and then continue over. Continue until the wall is complete.

Tip- it’s helpful to have extra lights on the wall that’s being smoothed. That way it’s easier to see any imperfections or ridges while working.

Let the joint compound dry. Most textured walls will need 2-3 layers to get a smooth surface. Once it’s dry, add another coat until it looks good.

On the last coat, we just touched up small problem areas with a 6″ joint knife to finish it up.

Here’s how the wall looked after 2 coats of joint compound.

Now, here’s the same wall with 4 coats of joint compound. It’s glassy smooth!

When cleaning up after applying the joint compound, it helps to use a painter’s multi-tool to scrape the roller cover as clean as possible.

step 5- sand

Once the wall is smooth enough, use a fine drywall sanding block to lightly sand any imperfections. The taping knife smoothing the joint compound will mostly leave a flat surface. So a quick sanding should clean up any bumps of ridges.

Make sure to wear a mask while sanding. The dust can irritate your eyes, nose or throat. Down the road it can lead to health issues. So make sure to put on a mask!

After sanding, vacuum the wall to remove dust left from sanding.

Next, use a slightly damp rag and wipe over the wall to remove any leftover drywall dust. You don’t want it too wet because the joint compound is water soluble, so if you clean to much it will damage the finish. Now the wall is ready to be primed!

step 6- prime

Finally, prime the smooth drywall. Apply at least two coats. Note, make sure to use primer. It’s less expensive than paint and will prep the walls for paint or wallpapering. If this step is skipped, you’ll need lots of extra coats of paint. So it’s best to just prime since it saves time and money.

This is the last step that’s needed to prep for the smooth wall for paint or wallpaper. Let the primer dry 24 hours.

how long did it take?

The walls in the craft room were very textured to begin with. We ended up applying 4 layers over 5 days. One layer was done each day. With it being cold outside, the walls almost needed 24 hours to dry.

This isn’t a necessarily a hard project, but it is tedious. So if you have patience and a few days, you can have a smooth wall!

after

Once the wall was smooth and primed, I finished the rainbow wallpaper on both sides of the wall.

When I did the first side, the texture showed through the wallpaper. I’m not a fan of that, so it was good to apply the skim coat for a nice clean finished look. The best design is when the details are thought out and clean and I think this looks much better!

It feels good to know a new skill. And I may or may not want all my my walls perfectly smooth from here on out- lol!

I hope this post is helpful to you! Please let me know if you have questions. I hope you now know how to smooth walls and can repeat this process in your house too.