How to Seal Sandstone Bricks

What You'll Need
Impregnable sealer
Spray bottle
Mixing stick

Sandstone bricks are commonly used in the building of fireplaces, patios, small decorative walls, and garden walkways. This material is easy to work with, provides a great look, and is relatively inexpensive. In some instances, sandstone bricks can be made with the right combination of ingredients. One of the problems with sandstone bricks is that it is very porous. Whenever sandstone bricks are used for a project, it is important that a sealer be applied.

Step 1 - Purchase Sandstone Brick Sealer

There are many different sealers on the market today. When buying the sealer for the sandstone bricks you must by a fluoropolymer based sealer. This sealer will impregnate the porous property of the sandstone bricks in order to block off any channels that water may seep into. This type of sealer can be easily found at your local hardware store.

Step 2 - Clean Sandstone Bricks

Before the sealer is applied to the sandstone bricks, they must be clean of any dirt or residue left over from the installation. Since the sealer must be able to penetrate into the sandstone itself, any type of dirt that gets in the way will give water a chance to cause cracks. Clean the bricks with a moist rag, brush, and vacuum.

Step 3 - Mix Sealer

Take the can of sealer to the area where the sandstone bricks are and remove the cover. With a mixing stick, not a power mixing attachment, mix up the sealer until it is a smooth consistency. It should not be like water, but a thick paint. As you mix the sealer keep it smooth instead of stirring it excitedly. This could cause air bubbles to be captured within the sealer that can cause weaknesses in the coverage.

Step 4 - Apply Sealer to Sandstone Bricks

Using a medium brush, with soft bristles, start to paint the sealer onto the sandstone bricks. Start in the far corner of the area where the bricks are installed and work across the top of it. Then continue to work down the item until the entire area is completed. Overlap your brush strokes by a few inches and always keep a consistent amount of sealer on your brush. Do not paint it on until the brush runs dry.

Step 5 - Spray Corners

If there are any corners, or edges within the area where the sandstone brisks are installed, use a spray bottle in order to get at these areas. The spray bottle will provide coverage to the area without causing any type of clumps of unsealed surfaces.

Step 6 - Apply Second Coat

Allow the sealer to dry for several hours until it feels "tacky". This means that when you touch it, it is not wet, but is a little bit sticky. Mix up some more sealer and brush it on in the same way that you applied the first coat. Continue with the application until the entire surface has been covered.

Step 7 - Finishing Touches

If this is a first installation of the sandstone bricks, you will be able to grout the seams of the bricks once the sealer has been applied and dried.