Need to know if the new stone tile, paver or existing installation is already effectively sealed, partially sealed or not sealed? Or whether it can be sealed at all?

Determining if a stone is sealed is an important question which must be answered prior to considering the application of a new sealer treatment. Realising if an unsealed stone surface will be able to accept a sealer is also critical in determining how to move forward. There is a simple “Water Test” that will help you determine, not only if the tile is sealed or not, but give you a guide as to what sealer should be used.

  1. Apply water to a few different areas of the stone and/or grout.
  2. Make each application of water approximately 25mm in diameter.
  3. Measure the approximate size of the circle of water, without disturbing the water, and make a notation of position and size.
  4. Place a drinking glass over the water to protect it from evaporation and let is sit undisturbed for 20 minutes.
  5. After 20 minutes, remove the glass and observe the results.

No change – If the water appears the same as when it was applied and the water measures the same diameter, then a sealer is already present or the stone/tile is very dense and does not sealing. In fact, a very dense stone/tile may not accept a sealer (since absorbency is necessary for a material to accept a sealer).

Slight change – If the water is still present in a bead but appears to be absorbing into the surface, then a sealer may already be present but requires re-sealing. Or the stone is not sealed and is sufficiently dense enough to allow for slow absorption of water.

Complete change – If the water is completely absorbed into the surface and the spot appears to have grown in size, then the stone is not sealed and the use of high-quality sealer is recommended.

This quick and easy test can provide valuable information about the current state of the stone surface. It will not only help you determine if a sealer is present or required, it can also provide good information as to how many coats and what sealer to apply.

Another useful tip: if the water is being absorbed slowly and you surmise a worn sealer application, you can confirm this with another simple test. This is carried out by cleaning a small inconspicuous area with a heavy duty cleaner to remove any existing cleaner and then perform the “water test” again.

If the water absorbs more quickly than previously, you should treat the entire area before the new application of sealer. If there was not change in the rate of absorption, then there was not likely any sealer present and the new sealer application can be made.

For this and other useful tips when deciding whether you can seal, or how much sealer can be used, contact the sealer manufacturer.

By Fred Gray, technical service manager, Laticrete