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What you'll need:
TOOLS
Paint tray
Paint roller
Squeegee and taping knives
Drop cloth
Drywall tape
120–150-grit sandpaper
Paint stir sticks or stirring drill attachment
SUPPLIES
Painters tape
Drywall primer
Joint compound
Knowing how to skim coat a wall is a skill that will always come in handy. With it, you’ll always have the ability to fix up imperfections in a drywall’s finish or to revamp the texture of your walls altogether—and at a fraction of what it would cost to hire a drywall contractor.
Whether you want to give your interior walls a smooth finish or finally hide the imperfections you can’t bear to look at any longer, applying a skim coat will give you the results you’re looking for. Use this guide to learn exactly which tools you’ll need, and how long the project will take for both beginners and avid DIYers alike.
Prepping to Skim Coat a Wall
Because the objective of skim coating a wall is to establish as smooth of a finish as possible, it’s important to take a few preparatory steps to ensure that is the case. Here’s what you might need to do beforehand to guarantee the best possible results.
Whether you’re painting, skim coating, or demolishing a wall, it’s always a good idea to protect the rest of your home with a drop cloth and painter’s tape. Cover all areas that might be affected, and affix the cloth to your baseboards or to the bottom of your wall with tape to prevent any slipping or sliding.
Next, unless you’re working on a blank wall, you may need to remove wallpaper. The cost to remove wallpaper for a pro averages almost $800, so you may want to DIY if at all possible. Fortunately, removing wallpaper is pretty easy in many cases.
If the walls have paint on them, you can take a few steps to prep the walls before you skim coat. You’ll want to clean the walls, removing any grime or flaking paint.
If the drywall has significant damage on it, such as torn tape, dents, or holes, you will want to repair these first. The average drywall repair cost is almost $600 for a pro, but it depends on the extent of the damage and the size of the repair required.
This step ensures that your joint compound will adhere properly and provide a smooth surface for all your future wall-painting projects. Use a paint roller to apply an even layer of primer to your wall. Rather than attempting to do the whole wall at once, roll on the primer from the outside in, working in squares until the entire surface is covered. Let it dry before moving on to the next step.
Mix Joint Compound
The joint compound that you will use when learning how to skim coat a wall needs to have a much thinner consistency than typical joint compound, also called drywall mud. When skim coating, you will be applying it almost like paint, requiring a thick liquid consistency.
You can use joint compound that you buy premixed in a tub or that you buy in a powder form and add water. Use a mixer attachment on a common household drill to stir the joint compound.
Premixed: If buying premixed mud, it will be the consistency of thick peanut butter. Add a bit of water and mix it in carefully. Slowly add more water until you end up with a consistency that’s close to pancake batter.
Powdered: Mix the powder with the amount of water recommended on the container for the powder. This should create a consistency in the mud similar to thick peanut butter. You can then slowly add more water and mix it in until you end up with a consistency close to pancake batter.
You may want to mix the joint compound in a larger bucket than you actually need, as it could splatter while using the mixer attachment, especially as its consistency becomes liquid.
Pour the mixed joint compound into a paint tray. Gently dip the paint roller into the tray until covering the roller in a thin, even layer of joint compound. Then apply it to the walls similar to applying paint. Work in vertical sections, about three to five feet in width, along the wall. Work from the ceiling to the floor. Once you finish one vertical section, move to the next step.
Smooth Imperfections With a Squeegee or Taping Knife
Once you finish a vertical section of the wall, you need to smooth out the skim coat before going to the next section. Make use of a magic trowel, a squeegee, or a taping knife to smooth out the mud.
Start at the top of the wall at the ceiling and work downward to the middle. Use gentle pressure and drag the squeegee downward to smooth the wall. Any extra mud in the high spots should fill in the low spots during this process. Then work from the floor toward the middle of the wall in the same section.
As you are smoothing out the section, you may end up with a bit of mud left on the squeegee or taping knife. If so, use a towel to wipe it clean.
After finishing one section, use a spotlight to look for areas you may have missed or areas that have too much mud on them. Shining the spotlight from the side can reveal areas with imperfections. Fix them with the squeegee or, if the mud is becoming too thick as it dries, use a taping knife. You can also spray water onto any area you’re trying to fix to temporarily soften the mud.
Try to make the section as smooth as possible (keeping in mind that you can sand later, so it doesn’t have to be perfect in this step).
Continue working on Steps 3 and 4 in slightly overlapping vertical sections until you finish the entire width of the wall.
Apply Additional Coats (if Necessary)
After the wall dries, inspect it with the spotlight again. How long does it take drywall mud to dry? It depends on many factors, but because of the thin layer used in skim coating, it may completely dry within 30 minutes to four hours. Thicker layers for mudding and taping drywall can take 24 to 48 hours to dry, so mud for skim coating dries much faster.
Upon inspection, it may not be quite as smooth as you would like. The smoother it is, the less sanding you’ll have to do later.
To further smooth it, consider adding a second skim coat of mud. You can add additional coats as desired. Follow Step 3 again to apply the new coat.
In Step 4, use the squeegee or taping knife at a right angle. For the first coat, you should use it vertically, dragging downward from the ceiling and upward from the floor. For the second coat, drag the squeegee horizontally in your section. For a third coat, go back to using the squeegee vertically in the section. Continue alternating the direction of the squeegee for each subsequent coat.
Once the final coating of the joint compound has dried, use sandpaper to smooth out any remaining imperfections. Opt for a hand sander over an electric one because the latter may remove too much and create more imperfections.
DIY Skim Coating a Wall vs. Hiring a Pro
The cost to skim coat a wall for a pro ranges from $500 to $600 on average for an entire room. On the other hand, it can cost as little as $100 to do it yourself, depending on how many of the tools and equipment you already have on hand.
If you know how to paint walls, you probably can learn how to skim coat a wall successfully. However, this is a process that requires more patience and time than a typical painting job. It’s also a job that can be messier than painting.
If you are someone who struggles to stand in place for long periods of time to do precision work like smoothing and sanding, you may prefer to hire a pro.
Applying drywall mud is a job where the experience of a professional can be invaluable. Pros know how to work with this material and make it smooth much more efficiently than someone who’s trying this type of job for the first time. However, you can learn how to skim coat a wall successfully if you’re willing to put in the time.
If you decide to try to hire a pro to do the work, the pro may quote you an estimated cost based on drywall finish levels, which may be a confusing term for you. These levels range from Level 0 to Level 5, and skim coating represents Level 5. The Level 5 skim coating is the most expensive level of drywall finish work when hiring a pro.
Frequently Asked Questions
You certainly don’t have to skim coat new drywall. However, if you want to paint on almost perfectly smooth drywall, skim coating is money well spent. If you have no plans to paint the wall, you probably don’t need to spend money or time on skim coating. For example, if you plan to leave the space unfinished or if you will cover the drywall with shiplap, there’s no reason to skim coat it because the quality of the finish on the drywall is not important.
Most people will skim coat the entire wall unless unusual circumstances exist. If you have a couple of areas of a wall that have a bad finish, you can apply a layer of skim coat on those areas to smooth them, improving the look. If the bad areas are widespread, though, you may want to skim coat the entire wall to fix everything at once. If you plan to add any of the different types of wainscoting to the wall, you only need to skim coat the part of the wall that the wainscoting won’t hide.
Multiple drywall texture types exist, but you can skim coat over almost any of them to create a smooth finish, if desired. However, the skim coating process differs when going on textured versus non-textured walls. For the textured wall, you need to use a thicker layer of mud that has a consistency similar to smooth peanut butter to cover the texture. For the non-textured wall, you can apply a thin layer of mud with a paint roller, using mud with a consistency like pancake batter. Add water to the mud to achieve the desired consistency.
You can apply skim coat over a painted wall, as long as you follow a few key steps. Start by cleaning the wall thoroughly, removing any dust or greasy spots. If you’re going over glossy paint, rough it up a bit with fine-grit sandpaper, so the mud will adhere better. You also should use a drywall primer over the top, whether you have glossy or flat paint, to help with adherence. Once everything dries, you can start the skim coating process.
You can skim coat over wallpaper, but you must follow a few techniques. Start by removing any loose segments of wallpaper. The less wallpaper you have to remove, the faster the job occurs, but loose wallpaper must go. Additionally, it is difficult to skim coat over highly textured wallpaper, so you may need to remove all of it in a case like this. Apply a stain-sealing primer over the wallpaper. This prevents the wallpaper from absorbing the mud. After the primer dries, you are ready to start the skim coating process.
Kyle Schurman has a passion for writing about topics ranging from home improvement to consumer electronics. His writing appears in online publications like Business Insider, New York Magazine, Scary Mommy, and multiple Tribune Publishing websites.
Kyle Schurman has a passion for writing about topics ranging from home improvement to consumer electronics. His writing appears in online publications like Business Insider, New York Magazine, Scary Mommy, and multiple Tribune Publishing websites.
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