How to Make and Apply Your Own Limestone Sealer

A limestone fireplace.
What You'll Need
Tung oil or linseed oil
Citrus solvent
Spray bottle

Using a natural limestone sealer is not only healthy; it is also safe for the environment. When deciding to seal limestone, make sure that it is necessary because some limestone applications do not need to be sealed at all. Not sealing it will preserve its natural beauty and breathability. However, if it is indeed necessary to provide the limestone with a membrane to protect it from constant staining and water infiltration, then make sure to use eco-friendly products. Here is how to make and apply your own limestone sealer.

Step 1 - Choose the Best Sealer

Limestone sealer can be made with linseed oil, Tung oil, or beeswax. Linseed oil mix is a good sealer but is recommended only if darkening and discoloration is not an issue. Tung oil mix dries completely and does not cause any discoloration after its application. The last option is beeswax. This product does not need any special mixing and can be used as is.

Step 2 - Mix the Ingredients

For linseed oil or Tung oil mix, simply mix one part of either product with one part of citrus solvent in a container. Sometimes, mineral spirits can be used as an alternative but only when there are no citrus solvent products available. The mix requires the same proportion of solvent.

Step 3 - Apply the Limestone Sealer

Remember that limestone is a very porous stone so make sure to work on the application as quickly as possible. Never leave a thick coating of the mix on the surface of the stone for a long time because it will be absorbed easily and cause uneven darkening. Dip a cloth in the mix and apply it thinly on the surfaces of the limestone. If not, use a paintbrush or a spray bottle to apply the sealer.

When using linseed, it is very important to spread only a thin layer of the mixture on every coating. Never spread a thick coating because linseed takes longer to dry than Tung oil. Allow the first coating to dry for about 24 hours before applying another coat. At least two or three thin coats of linseed oil mix are ideal.

For Tung oil mix, all coatings except the last should be spread thinly. After applying one or two thin coats of Tung oil mix, apply a thick coat for finishing. While the thin coats may take at least eight hours to dry, the last thick coat may take about two to four days before it dries completely.

The beeswax is very easy to apply but it may require constant application. To apply the beeswax, simply place a decent amount on a cloth, spread it on the stone and buff immediately. Be careful not to apply too much wax though.