How to Use a Grinder to Remove Thinset From Concrete

Thinset is a cementing material generally used with tiles as an adhesive to a concrete slab. Hardened thinset is as strong as concrete, and cannot be removed with chemical means. In order to remove a layer of thinset from concrete you'll have to employ physical force. Fortunately, a grinder can be used to do most of the work for you, removing the necessity of applying the force directly with a hammer and quickly removing the thinset, revealing the concrete layer beneath.

Difficulty: Moderate

Instructions

Things You'll Need:

• Dust mask
• Safety goggles
• Floor grinder
• Broom

1. Obtain a large electric floor grinder from a home improvement store or equipment rental shop.

2. Put on your dust mask and safety goggles before grinding the floor surface.

3. Plug the grinder in and start with a corner of the room. Turn the grinder power on and walk behind the machine, guiding it over the thinset surface for a first pass. The surface of the thinset may be rough, and applying force can damage the grinding surface. Raise the grinding surface so that it's barely touching the thinset for this first pass. The first pass should be made with light pressure applied to the grinder to smooth out the thinset surface.

4. Make a second pass over the thinset surface. Lower the grinding surface to the floor and apply more force to the grinder on the second pass to bite deeply into the thinset surface. This pass should completely grind the layer of thinset, revealing the concrete slab below.

5. Sweep up the debris and dust left from the grinding process on the floor with a broom. Inspect the floor for any remaining thinset. If the second pass left patches of thinset on the concrete slab surface, move the grinder to those areas and go over them again until the thinset has been completely removed. Sweep and grind patches of thinset as necessary.

6. Clean the surface with warm water to wash away any remaining residue from the thinset to finish the removal process.

Tips & Warnings

• The dust created during the grinding is hazardous to your health, so take care not to inhale it.

References

• HowtoInstallFlooring.com: Rip Flooring

Resources

• Blastrac: Removing Thinset and Leveling Your Surface