Reworking a new floor is, like any major remodeling work, an intensive and tedious process that can be difficult to pull off if not done correctly. This is especially true for tiles, which tends to use strong adhesives like tile mastic to keep the tiles bonded to the concrete floor underneath.
While the process of removing tile mastic will take some time and a bit of elbow grease no matter what you do, following the right method will at least help avoid any additional problems that could arise. And in the following paragraphs, we’ll show you exactly how to do it.
What is Tile Mastic?
Before we can properly tackle removing tile mastic, we must first understand what it is. Tile mastic is a natural resin collected from the mastic tree and is typically collected in the form of small, dried pellets. With a bit of processing and a few extra ingredients added, the mastic becomes the tile adhesive you see today.
Now, tile mastic has a few important qualities that set it apart from other adhesives. For one, it is highly viscous and can be a bit difficult to apply. Once it cures, tile mastic turns into a tough resin with a very strong bond. But most importantly, mastic-based adhesives are partially soluble in water.
It is here that we can start our process.
Removing Tile Mastic, Step by Step
- Prepare your materials.
To get started with our tile mastic removal process, we will need to prepare our materials. Unlike some of the other methods we will discuss later, the process we will be using is much safer and doesn’t involve the use of any dangerous chemicals.
You will need some cloth rags, a scraper, and lots of water. Obviously you will want to get more materials and hands on deck if you will be working on a larger area, so
- Expose the mastic.
Our next step would be to expose as much of the tile mastic as possible. Remove any obstructions on the floor you will be working on, like furniture, decorations, and other fixtures, then remove the tiles on the floor to reveal the mastic underneath.
You can use whatever method you like here, although what you end up using will depend on whether or not you will be using the old tiles somewhere else afterward.
If you will be repurposing the old tiles, a hammer and bolster is probably preferred to minimize damage to them, but a jackhammer is the faster and easier choice if you simply want to clear the floor out.
- Soften the mastic.
As we touched on earlier in this article, tile mastic can dissolve in water. However, the added ingredients in most commercial adhesives helps prevent the mastic from dissolving completely in its intended application (say, when you are cleaning the floor or have accidentally spilled water over it).
We can use this knowledge to our advantage. Take several cloth rags and place them over the tile mastic, then prepare boiling water and pour that over the rags you laid out over the floor. The mastic will not necessarily dissolve in the water, but it will soften the mastic significantly.
You have a couple of other alternatives here. For instance, you could use lukewarm or cold water if you don’t have hot water on hand, but hot water does help soften the mastic more quickly. You could also mix the water with vinegar to help break down the mastic chemically.
In any case, this process will take a bit of time—somewhere in the range of 30 minutes to an hour. Throughout this period, you will want to keep the rags wet to continue softening the mastic enough for the next step.
- Remove the adhesive.
Now we reach the satisfying step of finally removing the tile mastic. All you need to do here is to take your scrapers, bolsters, or other tools and remove the mastic until there is none left.
As you scrape away the mastic adhesive, try to avoid missing any spots, because these spots will harden back into its tough mastic form if allowed to dry out. To prevent this problem from happening, you can use your wet rags to keep portions of the mastic soft before you reach those areas.
If some small spots of mastic does end up hardening, though, removing them can be done with a bit of bolster work.
- Prepare the floor.
With the mastic finally removed, you should now have a nice and clear concrete floor. But before you can go ahead and replace your flooring, you should perform a bit of additional cleanup and preparation to allow the concrete to accept the new flooring without any issues.
For instance, you are bound to still have some bits and pieces of mastic adhesive on the floor after you’ve removed most of it. You can use some of our tips we explained in the previous step to remove these.
Once that is cleared, you will need to sand and polish the floor to remove as much of the rough debris that could cause uneven floor installation later. The process should be no different from any polishing work—start with sanding with a rough grit, then clear the dust and repeat the process with finer and finer sandpaper.
And with that, your concrete floor should be ready to take on whatever your next project will be.
Alternative Methods of Removing Tile Mastic
In this article, we’ve shown you what we feel is the best way to remove tile mastic from concrete floors, but there are indeed other ways to do the job.
For one, there are specialized chemicals that are designed to dissolve mastic and other tile adhesives, but they tend to use harsh substances that can be dangerous if they are inhaled or come into contact with skin.
Other builders might opt to use more physical methods to remove the tile mastic—that is, with hammers and chisels—but this will only take longer to finish and can put you at risk of injury from repetition or from an accident.