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, anyway 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, 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.
The levels of 3, 4, 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 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 wall should look completely flat and will not have any imperfections, even in 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 a Skim Coat When Painting Walls?
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 over time 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 Skim Coat?
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 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 it.
This means rooms with any skylights or hallways with lots of light sources should probably have a level five finishes applied to it.
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 with gloss or semigloss paint, as other reflective paints will show the mistakes in the skim coat.
In a similar way, they suggest you to 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.
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 skim coating requires 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 paint brush – 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, on 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 are relatively straight forward, but can be hard to get perfectly correct.
Skim coating is a lot easier said than done.
If you follow these 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 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.
This will help your compound stick and seal the wall better.
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.
Step 4: Repeat and Sand
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 walls as 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 eaiser.
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 on the plastered wall for achieving smoother finish.
While on the other hand, plastering is a broader term which includes skimming as one of the whole processes.
In simple terms, you can say that skimming is a part of a 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 service can be classified into 3 types. These include:
- Lime plaster: Traditional plastering done using sand, lime, and water
- Cement plaster: This is done on the masonry work using cement, sand, and water
- Gypsum plaster: Thick plaster coat done on walls with calcium sulphate and water
While a backing plaster will take around 4-6 days to dry, skim coat should take 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 includes:
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 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 looks old, tired, and dingy, you can improve their appearance by adding 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 texture, 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 even 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.
Jack Luis is a semi-retired painter who loved painting his clients’ ideas on their walls. He had worked as a painter for more than a decade to serve the customers in areas such as Charleston, Mount Pleasant, Beaufort, Georgetown, SC (South Carolina). Today in his free time, he likes to read and write about the newer techniques that are being implemented in his profession. You may read more about him here or get in touch with him here.