How to Seal Slate Porch Tiles

Sealing slate porch tiles is necessary. It is done to protect the porous surface of the slate tiles and add a finish to the porch. This can keep the stones in good condition for many years to come. When deciding to seal the porch tiles, it is important to come up with a good plan before doing anything else.

Tools and Materials Needed:

  • Natural stone sealer
  • Paintbrush
  • Cleaning materials
  • Natural stone cleanser (pH 7)
  • Brush
  • Respirator
  • Eye goggles

Step 1 – Preparations

Mix mild detergent in water and use it to clean the surface of the porch. Use a brush to get rid of grout residue. Wash thoroughly with water and then use distilled water as your last rinse to prevent discoloration. Allow the surface to dry. Keep in mind that the sealer cannot be applied if the porch is dirty and still damp.

If this is the second time that you will seal the slate tiles, you have to apply acetone stripper on the surface to remove the old sealer. Wash with natural stone cleanser instead of detergent to neutralize the surface (since you used a chemical stripper). Next, proceed with the steps above on how to clean and prep the surface.

Step 2 – Choose a Sealer

Decide whether to use a sealer that will provide a glossy finish or a matte finish. The glossy type will give the porch a wetter or shinier look. However, it is best to go with a matte finish in order to preserve the natural look of the stone as much as possible. 

There are 2 types of sealers to choose from: penetrating and topical. Topical sealers will only seal the surface of the stone, but a penetrating sealer will seep into the pores of the stone, thus giving it better protection. In addition, penetrating sealers are best for exterior tiles and are less likely to require resealing. Thus, it is best to settle for penetrating natural stone sealers instead of topical types.

Use polyurethane sealers if you want to deal with sealers that have the lowest toxicity levels. These sealers are more popular due to this reason. This type of sealer also does not cause the stones to crack or turn yellowish after some time. Buy the preferred type of sealer from a home improvement store or a masonry supply store.

Step 3 – Ensure Safety

When working with chemicals, be sure to wear a respirator for protection against toxic fumes. Although the work will be done outdoors, a respirator still offers additional protection. Wear eye goggles and protective gloves as well.

Step 4 – Apply the Sealer

When the tiles and grout are dry and clean, prepare the sealer according to manufacturer’s instructions. Apply the sealer with a paintbrush or a paint roller. Always follow the direction of the grain and keep the coating even. During the first coating, apply only a thin layer. Let the sealer set for about 2 to 4 hours or so. Check the label for the recommended setting time. When the first layer is dry, apply second layer. Keep the layer thin, but thicker than the first one. Let the sealer dry for the recommended time before walking on the porch one again.