Can You Plaster Over Ceiling Tiles?

Last Updated on October 9, 2022 by Barry Gray

Can You Plaster Over Ceiling Tiles

Ceiling tiles are either a hit or a miss. If you love them, then you probably wouldn’t be here right now looking for ways to cover them up! Plaster is perhaps the most common material to cover old ceilings, but many tradesmen are reluctant to cover them without removing tiles first.

So, can you plaster over ceiling tiles? No, you shouldn’t because it can cause structural issues and fire hazards. In fact, many building codes prevent you from plastering over certain ceiling tile materials, so you wouldn’t be allowed to even if you want to. However, you can easily remove the tiles and plaster the ceiling in no time.

Throughout this article, you’ll also learn:

  • A step-by-step process for replastering a ceiling with tiles
  • Risks involved with plastering directly over ceiling tiles
  • Numerous common questions that come with the job

How to Re-plaster if You Have Ceiling Tiles

Since you’re not supposed to plaster over ceiling tiles, you can work around it by removing them and starting the project with a clean slate. Contrary to popular belief, it’s actually very simple, and it doesn’t require much time to get everything ready to go.

The supplies you’ll need are as follows (links to Amazon provided too):

Once you get your tools for the task, you’ll be ready to follow the instructions below.

  1. Remove everything from the room. You don’t want any rugs, furniture, appliances, or anything else in there. They could get covered in plaster and other materials, but they’ll also be an obstacle in your way when you’re trying to move the ladder around. When you’ve removed everything, cover the ground with a thin plastic sheet.
  2. Take the putty knife and slide it under a tile in the corner. It’s always a good idea to start in the corner so you can work your way around the edges. Try to move in a spiraling motion to remove every last tile before you start the next step. Go at a 45-degree angle to prevent the tiles from breaking off in chunks.
  3. Use the putty knife to remove residue from the ceiling. Never let the tile break in half, or you’ll have a much bigger and more frustrating mess to clean up. Polystyrene is especially annoying to deal with if it breaks apart, so do your best to clean up and vacuum the area as you go.
  4. Starting with the far corner from the center, use your plaster to slowly move inward. Use a plaster hawk, such as the Marshalltown Aluminum Hawk (link to Amazon), to load up the plaster. Spread it smoothly and at a steady pace to ensure that you get an even layer rather than clumping or thinning.
  5. Use the plaster float to glide along the whole surface of your plastering job. This will smooth everything out even more by lowering hills and filling valleys. Never start plastering without using a plastering float unless you’re going for a natural uneven appearance.
  6. Vacuum the whole area once more to remove any plaster or bits of the previous material on the floor. You’ll obviously have to remove the thin plastic sheet first, but once you do, go over the whole floor and even the walls with cleaning supplies. The longer plaster sits, the harder it will be to remove.

That’s all there is to it! You can’t plaster right over ceiling tiles, but you can definitely remove them and plaster the ceiling very quickly. Contrary to popular belief, ceiling tiles aren’t very durable, especially the ones that have been around for a long time.

Are There Any Risks?

As with all DIY projects, there are risks of plastering over ceiling tiles. As mentioned multiple times throughout this article, you should always remove the tiles first. Let’s examine all the possible risks that you could encounter if you decide to skip the removal and go straight to plastering on top of it all.

  • First and foremost, the biggest risk of all is that it’s a fire hazard. Polystyrene makes up the vast majority of budget-friendly ceiling tiles, and it’s highly flammable. Not only that, but when it catches on fire, it can be toxic to breathe in. If you layer plaster on top of the material, you’ll increase the temperature and make it more susceptible to catching fire.
  • Since plaster weighs quite a bit, it will eventually start to pull down on the tiles. You might not notice it right away, but there’s no doubt that you’ll end up with cracks and slouchy spots throughout the ceiling eventually. In some cases, entire tiles will fall through the plaster and leave a massive hole.
  • Another issue is that most tiles aren’t designed to have plaster on them. They’re not porous enough to hold a strong grip. The plaster will eventually start to drip off each of the tiles, making it look incredibly tacky and hazardous. Many tradesmen find that it’s not even possible to keep it on while doing the job.
  • According to the community of My Builder, tradesmen recognize the fumes that are put off by combining polystyrene and plaster. Although polystyrene isn’t the only type of ceiling tile (there’s also cork, plastic, and many others), it’s the most common type. By mixing plaster and styrofoam, you’re asking for a disaster.

As you can see, there are many different risks involved in the process. It’s always a better idea to just remove the tiles first. If you’re dealing with a professional who doesn’t want to do this step, then you should look elsewhere.

Common Questions

If it’s your first time plastering a ceiling or removing tiles, then you probably have a few questions and concerns. Don’t worry! You’re covered with everything you need to know below…

  1. How do you remove ceiling tiles without breaking them? You need to use a putty knife at a 45-degree angle to slowly elevate the tile off the adhesive. Wiggle the putty knife back and forth until the tile starts to lift all the way. Remember to start in a corner, so you have a good open side right away.
  2. How long does plaster last once you’ve put it on the ceiling? All plaster is designed to last different lengths of time, but the average plaster lasts between 5 to 15 years. After that, it’ll start to flake and become discolored.
  3. How long does plaster take to dry? Plaster takes about 1.5 to 3 hours to solidify on the exterior layer and between 4 to 6 days to dry completely. Temperature, humidity, and many other factors can increase or decrease the speed of drying.
  4. What are ceiling tiles made from? Ceiling tiles are mostly made out of polystyrene, but they also come in plastic, cork, fiberglass, mineral fiber, clay, cellulose, and more. The main two reasons that people remove ceiling tiles are that they don’t look too great in some homes, and many of them contain a toxic chemical known as asbestos.

Conclusion

Unfortunately, you can’t plaster over ceiling tiles. The adhesive holding up each tile isn’t strong enough to support plaster, and it’s also a serious fire hazard. These two reasons, among many others, are enough to prevent any honest tradesmen from accepting such a job.

The good news is that ceiling tiles are fairly easy to remove, providing a smooth surface to plaster over.

Photo of author

Barry Gray

Hi, I’m Barry. I’ve loved woodworking and bringing things back to life for more years than I care to remember. I hope my passion for tools comes across loud and clear in everything you read here on The Tool Square.