How to Skim Coat Your Walls Before Painting?

How to Skim Coat a Wall before Painting

If you have dabbled in painting or construction, you may have heard something called finished levels.

Essentially a finish level is how well finished a piece of drywall is on a scale from 0 to 5.

Zero tends to be completely unfinished, with no tapering and especially no skim coat, while a five is a perfectly skimmed and finished wall that you can shine a bright light on and would not be able to tell where the wall ends or begins.

When it’s about skimming the walls before painting, there are dozens of different ways.

Depending on who you ask there is a wrong way and a correct way.

IMO, either way, is correct if it brings you to the final product, a perfectly smooth wall.

In this article, I will be describing my personal favorite way to skim coat.

But before we come to our main questions of what, when, and how to skim coat, let’s try to understand more about the drywall finish levels.

What are the Levels of Drywall Finish?

Finished levels are an industry-standard set by the major drywall companies and are commonly used in this profession.

Contractors use the purpose of the wall in determining how much finishing is required.

For example, the guidelines only suggest using levels 0, 1, and 2 for areas that are generally out of view of the public such as an attic or a garage.

These levels have minimum tapering and especially no paint. While you increase the scale on the level, the wall generally looks better and better.

Levels 3, 4, and 5 are all more accepted by different scales of a similar thing. I mean that level three has tapering and to hide the seam, a wall texture is used.

This makes the wall appear much flatter; however, it will have a bumpy finish.

A level four wall will appear almost completely flat after it is painted with a minimum texture. It makes sense that a level four is better than a level three.

So, what about a level five?

A level five wall is the best of the best, where a skim coat is used on the entire wall to make it appear flat.

This high level of the wall should look completely flat and will not have any imperfections, even in an inspection under hard light.

The only way to get this best of the best level on your wall is to skim coat, as it completely removes all imperfections and hides the joints of the drywall perfectly.

What is Skim Coating?

Long story short, a skim coat is a small coat of drywall mud on top of a piece of drywall that helps become flatter.

When you build with drywall or have drywall exist in a home environment, it can become not flat overtime or naturally at the joints.

And who would want a bumpy wall?

A skim coat is able to fix all of your problems, relatively quick.

In fact, a skim coat is the only way painters and contractors have agreed to make a textured wall look smooth in bright light.

Also, the skim coat is the only way to meet the drywall level finish of five, which is the best of the finishes that are generally used on walls with bright lights.

When to do the skimming?

If you want to smooth out your wall (and hide imperfections) without plastering, sanding and skim coating the walls is a way to go for.

We mentioned it earlier, but not every wall has to be skim coated.

In fact, not every wall should be, as the skim coating is very time-consuming, and if you are doing it yourself, can be a tricky task.

Also, as we mentioned earlier, skim coats should be used on walls that will be heavily looked at and have a lot of light on them.

This means rooms with any skylights or hallways with lots of light sources should probably have level five finishes applied to them.

Or you can have a skim coat done in any room you want to look particularly perfect, such as a living room where you will host a lot of guests.

You can do it all through your house, but keep in mind, as it is a time-consuming process, it will increase your coat by a good amount, and some walls simply do not need it.

If you are working with a contractor, ask about skim coating and see what they recommend.

But, if you are working by yourself, consider only using a skim coat on the most important walls.

Drywall companies also suggest that a skim coat should be accompanied by gloss or semigloss paint, as other reflective paints will show the mistakes in the skim coat.

In a similar way, they suggest you do not use paints with textures such as eggshell or knockdown, as that kind of defeats the whole purpose of the flatness of a skim coat.

Just in case you find all this troublesome, there is a better alternative to skim coating walls and that is wallpaper or wall liners.

Mist coating is another good alternative to skim coat in which a thin coating is applied on a plastered wall as a substitute.

Put them up and stay relaxed for a year or two!

What is a Skim Coat

How to Skim Coat Walls Before Painting?

Skim coating can be a difficult task for even the masters of the trade.

However, you will only get better if you practice, and to practice, you have to do it.

What are the Items Required?

The bread and butter of the skim coating require a 14 inches squeegee knife and a regular old paint roller.

And of course, some drywall mud to actually apply the skim coat. But it’s not that easy.

There are actually a few things that I recommend you to use so you can have the best outcome possible.

Here is the list of items you will need for this project.


  • A Mud Pan – To hold the mud you are currently using
  • A painter roller and paintbrush – To apply the mud to the wall quickly
  • A squeegee knife and taping knives – To smooth out the coat of mud
  • Sanding tools such as a sanding pole and safety glasses – to smooth the wall at the end

Note: The roller sleeve that is used with the paint roller should match the size of the roller and should be the smoothest one you can find.

Those are the tools I recommend for the job.

You can pick up these all at your local paint store, or if you look, maybe even online, at stores such as Sherwin Williams or Amazon.

Just a quick note, the use of a squeegee knife and taping knives are heavily debated within this community, however, I stand behind the squeegee knife as a good alternative between knives as it is simply easier to use.

But I recommend having both on hand so you can personally choose which one you prefer.


All projects require a certain amount of materials, however lucky for us, the amount of materials is relatively short so you may already have some of them on hand.

If not, you can always pick them up wherever you gather your tools. The required materials for skim coating include…

  • Masking Tape and Primer – For preparing the walls
  • Drywall Mud / Compound – To hide the imperfections in the wall
  • 120 Grit Sandpaper – To smooth the wall out

The Steps

The steps are relatively straightforward but can be hard to get perfectly correct.

Skim coating is a lot easier said than done.

If you follow the following steps, anyone can be able to skim coat, at least a little bit of a wall.

So let’s just get into it.

Step 1: Prepare the Wall

Before you start to skim the coat, you will have to do some basic preparation of the wall.

First, you should add masking tape to the bottom and top of the wall and any other place you wish to mask off.

We will be applying primer and drywall mud to this area so if there is anything you don’t wish to properly damage, remove it, or mask it off.

After this, you can fill the holes (if any) and add primer to the wall if the wall is not primed.

A primer like Zinsser Drywall Primer or BM 253 primer (Benjamin Moore) will help your compound stick and seal the wall better.

So, you can use them fairly well for skim-coated walls.

Step 2: Add Mud

As step 2 is named, here is where you add the mud to the wall.

You can use a paint roller to apply the mud. The mud shouldn’t be too thick or too thin.

A good standard is that the mud should be applied to the wall and just barely not roll down it.

And this is called a skim coat, not a heavy coat, so go light on the mud and try to make it as smooth as you can.

Step 3: Smooth the Mud

This is the hardest part of the project at all since you have to be perfect in an imprecise task.

You will want to get your knives out and flatten the mud. Starting in a corner, pull down through the mud, removing in excess.

You will have to go up and down and side to side.

This is a difficult task, but don’t get frustrated. You may want to look up YouTube videos to learn the technique and the fastest ways.

Step 4: Repeat and Sanding

You will want to repeat step 3 a few more times for a total of two or three coats.

This may sound like a lot, but this will ensure you will get the smoothest plastered walls possible.

Also, since the coats dry relatively fast, you can complete this project also relatively fast.

After you have all of the coats applied, you will want to go in sandpaper and sand down any of the peaks, and just smooth it out.

I recommend using a manual sanding pole to help you reach up to heights. This will make the process easier.

What Joint Compound Is Best to Use for Skim Coating?
I have been using a general all-purpose compound for skimming since long and it works fine. It’s a type of pre-mixed mud for drywall that is available in buckets or boxes. Make sure you thin out the compound with water and mix well before applying.

Difference between Skimming and Plastering

While plastering and skimming may seem to be similar for many, it’s not the same.

Before you try any of these processes, it’s important for you to know the difference between both of them.

Skimming is a process where a thin layer of mud coat is applied to the plastered wall for achieving a smoother finish.

While on the other hand, plastering is a broader term that includes skimming as one of the whole processes.

In simple terms, you can say that skimming is a part of the process of plastering the walls for getting a smooth finish.

While you can skim coat the walls without plastering, the process of plastering the walls isn’t said to be complete without skimming.

Furthermore, plastering services can be classified into 3 types. These include:

  1. Lime plaster: Traditional plastering done using sand, lime, and water
  2. Cement plaster: This is done on the masonry work using cement, sand, and water
  3. Gypsum plaster: Thick plaster coat done on walls with calcium sulfate and water

While a backing plaster will take around 4-6 days to dry, a skim coat should take a relatively lesser time to dry completely.

On average, it takes around 3 days for the skimmed surface to dry and be ready to apply the paint.

The cost to plaster, skim coat and paint the walls will generally depend on the job size, condition of the walls, and finish options you choose.

Skim Coating vs. New Drywall: What’s the Better Option?

If your walls and ceiling are looking shabby, getting new drywall is not the only option.

Depending on the condition of the current drywall, you can improve the way it looks through the skim coating.

Sometimes called level-five drywall finish, a skim coat fills in the dings, dents, and other rough areas of the existing drywall so you have a new surface that can be re-textured or painted.

It takes two layers of skim coating to do the job and there are good reasons why you should consider this alternative to putting up new drywall.

Some of them include:

1- New Installations

If you have new drywall added to your home or office, then adding a thin layer of skim coating is recommended.

A single layer can ensure that the surface is primed and ready for painting.

Adding skim coating is important because drywall may absorb the paint you apply differently compared to the joint compound and that will leave an impression.

By adding skim coating, you ensure that the paint will be absorbed evenly for the best look.

2- Repairs and Fix the Damage

If the drywall has been repaired either on the wall or ceiling, it’s going to stand out from the existing drywall.

By applying the skim coating, you can even out the surface so it can be re-painted or re-textured.

Additionally, if you are planning to remove the wallpaper before painting, removing old wallpaper can damage the surface of the drywall.

In fact, sometimes removing the outer layer of drywall paper may expose the brown paper that is underneath.

At this point, the brown paper will need to have a prime surface sealer applied before you can add a skim coating.

Otherwise, you will not be able to cover the damage.

3- Restore Old Ugly Surfaces

If your walls or ceiling look old, tired, and dingy, you can improve their appearance by adding a new skim coating.

This will create a new layer that is bright and will take years off the appearance of your walls or ceiling.

Sometimes the problem isn’t that the surface of the drywall or painted wood paneling is old, it’s just unappealing.

Outdated textures, colors, or patterns can make the surface quite ugly.

A new layer of freshly skimmed coat will provide a method of adding new texture, colors, or patterns that better suit your style.

Plus, you do not have to rip out the old drywall to get the job done.

The Bottom Line

Now you know a great deal about skim coating such as – what it is and why it’s important.

If you are working on a home project that involves adding a skim coat, you can do it yourself.

Skim coating is less expensive and far less time-consuming compared to adding new drywall.

So, if you are remodeling your home, needing to repair the damage, or just want to brighten up the look of your walls or ceiling, a couple of layers of the skim coating may do the trick.

After a skim coat, the next step is to paint the wall and you should be essentially there.

And by the time you finish, you will have a lot more appreciation for local contractors that provide these skim coating services.

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