How to Install Tile on Stained Concrete

Quick Column Summary:

• Tiling on stained concrete
• Clean floor with oxygen bleach
• Test thinset for bonding to concrete

Teresa Norrell, from Moyock, NC, has a pretty simple question.

"Can I install tile directly to a previously stained concrete floor?  I fear the thinset mortar will not adhere to the stained concrete."

Here's my answer:

Teresa, I don't think you'll have an issue at all, but here's how to ensure success.

opens in a new windowI'd clean the floor really well with my opens in a new windowStain Solver Certified organic oxygen bleach. This is a product I've made for nearly 20 years.

It will remove any dirt, oils, etc. that could interfere with thinset adhesion.

Then, I'd mix up a tiny amount of thinset - about the size of a baseball. Mix it correctly to the right consistency. I opens in a new windowhave a video series about this you should watch.

I'd apply this small amount to the floor in a corner out of the way. Use the notched trowel you intend to use for the job.

Allow it to set up for about 30 minutes, then cover it with a damp paper towel. The purpose of the paper towel is to try to get the thinset to cure. You don't want it to just air dry. In the real world, it would be kept damp by the tile that's covering it.

Every four hours spritz the paper towel with water. Leave it overnight.

After 48 hours - trying to keep it wet, lift off the paper towel.

See how well the thinset is bonding to the floor. I'll bet it's rock solid.