Skim coating is a stylish way to treat ceilings, especially drywall. Not only do you get a unique look, but the skim coat also protects your ceiling from things like cracks. Skim coating also helps to smooth out rough ceiling textures. But can you (and should you) apply a skim coat to any type of ceiling? Will skim coating work with ceiling tiles?
A skim coat may or may not work with your ceiling tiles, depending on the material that the tiles are made of, but you really shouldn’t. Sometimes,skim-coated ceiling tiles can change color or come loose. The safest option is to replace the ceiling tiles with drywall that you can then skim coat.
There isn’t an obvious answer about skim coating ceiling tiles, and there are many variables that you have to consider. But it is not recommended, and it could even be unsafe for you to do so. Let’s look at each of the possibilities in detail; then, you can decide if skim coating is the best option for your ceiling tiles.
Why You Shouldn’t Skim Coat Over Your Ceiling Tiles
You can skim coat over ceiling tiles. In saying that, we mean that it is physically possible to do so. Applying a skim coat is relatively easy, but it is an arduous task, and if you want to cover ceiling tiles with a skim coat, you could run into problems that make it less worthwhile.
Here are a few of the most crucial factors that you should consider before you skim coat over your ceiling tiles.
1. Sculpted Ceiling Tiles Could Be Difficult To Skim Coat
Ceiling tiles with designer patterns were all the rage forty or fifty years ago, and like all popular trends, this one has also returned with force. They can add a classic look to any room. But sculpted ceiling tiles don’t look good forever, and at some point, you may want to do something to make your ceiling look better again. Skim coating may seem like a good option.
The problem is that these sculpted ceiling tiles often have sizeable bumps and curves, making it nearly impossible to apply a skim coat properly. The general rule here is that the smoother the tiles’ surface is to begin with, the easier they will be to skim coat.
2. Ceiling Tiles Can’t Handle The Weight Of Skim Coat
Skim coat mud adds a lot of weight to your ceiling. Drywall ceilings, with their larger panels, can be more securely fastened to the rafters. That way, the ceiling can handle the added weight of the skim coat.
Unfortunately, that’s not the case with ceiling tiles. They are held in place by adhesives, delicate nails, or a thin metal grid. Ceiling tiles are made to be easily installed and removed, so they aren’t installed as solidly as drywall ceilings. Once you’ve added the weight of the skim coat, the ceiling tiles will probably come loose and start falling apart, causing your ceiling to collapse.
3. Skim Coating Over Ceiling Tiles May Cause Discoloration
Depending on the tiles’ material, there’s a genuine possibility that ceiling tiles may discolor the skim coat. This is due to how the tiles handle moisture, and since the skim coat contains water (and is often diluted further when you apply it), the moisture is absorbed by the tiles, leading to brown discoloration.
You can quickly solve this by painting over the skim coat with a primer and then another paint but painting over it defeats the purpose of applying the skim coat in the first place.
4. Some Ceiling Tiles May Lose Their Consistency With Skim Coat
Ceiling tiles are often made of gypsum, clay, cellulose, or starch. These are four materials that can’t handle moisture very well, and since a skim coat contains copious amounts of water, applying a skim coat to these tiles could actually damage the tiles rather than improve them.
If you skim coat over these kinds of ceiling tiles, the tiles will eventually crack, chip, and break. You are effectively ruining their consistency by applying a skim coat.
If your ceiling tiles are made of material better at handling moisture (like mineral wool or fiberglass), this should not be too much of a concern. However, most of the other negative factors will still apply.
5. The Spaces Between Ceiling Tiles Can Cause Problems
There are always boundaries between ceiling tiles. These boundaries could be spaces or thin metal strips, for example, and it’s a given that ceiling tiles will have these areas or separation between the tiles, unlike drywall sheets that can be applied with minimal gaps between them.
Applying a skim coat over these borders or gaps is nearly impossible. Even if you have metal strips, you will find that the skim coat will eventually crumble and expose the boundary underneath, making it look unfinished and rough.
Covering up the spaces or metal strips between the tiles with some masking tape will help. You can then simply apply your skim coat over the masking tape. But masking tape is a paper-based product that will absorb the moisture from the skim coat and weaken in the process. It may look neat for a few months (maybe even a year or so), but it will eventually show cracks and crumble.
Ceiling Tiles, Skim Coats, And Safety Concerns
The primary reason people choose to skim coat their ceilings, and may consider skim coating over their ceiling tiles, is when the tiles are starting to look bad. They may be old, crumbling, falling from the ceiling, or just be ugly. These are all fantastic reasons to want to cover them up.
However, apart from the impractical side of skim coating over ceiling tiles, you could be taking a massive health and safety risk, and covering the problem with a skim coat won’t solve it (and could even make matters worse).
When your ceiling starts to look bad, it’s generally an indication that it’s time to replace the tiles. This is especially true if they are falling apart. You can try to make the tiles look good again, maybe tape them up or add some adhesives, then coat them. But the ceiling tiles could still collapse at any time (especially with the added weight of the skim coat), possibly leading to severe injuries.
Some ceiling tiles (especially older ones) contain a harmful chemical called asbestos. It was a prevalent material during the 20th century, used to manufacture all kinds of things, including ceiling tiles. Its popularity has dwindled as medical science found asbestos to cause severe respiratory illnesses, even potentially fatal ones. But you can still find asbestos in older ceilings.
If your ceiling tiles contain asbestos and start falling apart, you are opening yourself up for a range of health issues. Skim coating will not stop the asbestos from spreading throughout your home.
And lastly, many ceiling tiles are a fire hazard. Some of the materials they’re made of are very flammable, which people either didn’t know about or care about a few decades ago. These decaying and collapsing ceiling tiles could cause some electrical wiring that runs over them to short-circuit and cause a fire, and no amount of skim coating will solve that problem.
Conclusion
Skim coating over ceiling tiles may seem like a good idea, and it could even look good. But it’s simply not worth it. Too many things could go wrong, both with the look you’re trying to achieve and with your health and safety. Perhaps that collapsing ceiling is begging to be replaced, not covered up, and maybe it’s time for you to give it what it’s been begging for.
Resources:
https://www.familyhandyman.com/article/skim-coat/
https://www.hunker.com/12307648/how-to-paint-old-ceiling-tiles
https://manhattan-nest.com/2014/08/25/ladies-and-gentlemen-may-i-present-ceilings/
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