Thinset is a material used to adhere tiles and other types of flooring to plywood subflooring underneath. If you plan on putting new floors in your home, you’ll need to remove the old floor and then remove the thinset from the plywood. You cannot put new flooring onto already hard and dry thinset.
Therefore, how to remove old thinset is exactly what we are here to teach you today.
4 Ways to Remove Thinset from Plywood
There are four main methods that you can use to remove thinset from plywood. Let’s take a look to see which of these is best for you. On a side note, the first step to three of these methods is the same, so we will cover this here.
Before you get to hammering or scraping, soak the thinset using water. Pour a good bit of water over the thinset and let it soak for at least an hour, preferably much longer. Thinset contains cement, so it will loosen up when it gets really wet.
Just don’t do this for method number four.
1. Using a Putty Knife
The first and simplest way to remove small amounts of thinset is by using a putty knife or putty scraper. Putty knives are very small handheld tools that are usually used for applying plaster and putty to walls, although they can also be used as scrapers.
Here, you are just going to use that scraper to scrape away the thinset. This method is best used if there isn’t too much thinset present and/or if it has already been significantly loosened. Hold that scraper at an angle to the thinset, about 45 degrees, and apply plenty of pressure as you push away from your body.
It’s a straightforward method, but it does require plenty of time, muscle, and effort. For this reason, we only recommend this method for small thinset removal jobs. You don’t want to use this method for big jobs though, because scrapers are small and the process will take far too long.
2. Using a Hammer and Chisel
The second way to remove thinset from plywood is by using a hammer and chisel. This method is a lot more efficient than using a putty knife or scraper. This is especially the case if you have a larger area to deal with, as well as if the thinset is not very loose.
As you can probably tell, you can generate a lot of force by hitting a hammer with a chisel, much more force than with just a scraper.
This is a decent method to use for small to medium size jobs, and for times when a normal scraper doesn’t provide you with enough force. Just hold the chisel at an angle to the thinset, a little less than 45 degrees, and start pounding it with your hammer. It also takes muscle and time, although less so than using a scraper.
3. Using a Hammer Drill
Perhaps the easiest way to remove thinset from plywood is by using a hammer drill with a chisel attachment. Hammer drills are fast and powerful. With the chisel head attached, you just need to hold the head at an angle to the thinset and pull the trigger on your hammer drill.
This is definitely one of the faster ways out there, although you may damage the plywood underneath a little bit. That said, if you need speed, then this is likely your best bet. It also requires very little effort on your behalf.
4. Using an Angle Grinder
The other way to remove thinset from plywood is by using an angle grinder with a diamond cutting wheel between 5 and 7 inches large.
This method is perhaps even faster and easier than the hammer drill method, although much messier. You definitely want that dust shroud attached on your angle grinder, and if possible, have it hooked up to a shop vac to suck that dust away. Hold the wheel flat against the thinset and get to grinding.
What Is the Best Way to Remove Thinset from Plywood?
If you have a lot of thinset that needs removal, and if it is really stuck on, then both the angle grinder and the hammer drill are viable methods. They’ll certainly get the job done much faster than using manual tools, such as the scraper or hammer/chisel.
Mistakes to Avoid, Tips & Tricks
Lastly, below are some tips to make the process easier:
- Soaking the thinset with water is fine for the first three methods. However, if using an angle grinder, don’t do this. You’ll end up with a huge mess.
- Thinset is not the healthiest material, and you don’t want to inhale its dust. Always wear breathing protection when removing it, even just a basic painter’s mask.
- The thinner the layer of thinset, the less of an angle you should use when utilizing a scraper or chisel.
Summary
Now that you know how to remove thinset from plywood, you can choose the method that works best for your situation. In case you need to remove thinset from concrete, check this article.