The primary goal of a masonry sealer is to stop liquid water from entering a hard masonry surface but also allow any accumulated water vapor to escape before any damage can occur. Water can readily damage most masonry surfaces after a few years of exposure.
In both its liquid or vapor form, water can cause cracking and change the alkaline nature of masonry materials. This will drastically weaken the hard material.
Water damage is very hard to fix once it has happened.
Using an appropriate sealer can prevent much of this damage before it occurs and is much cheaper than the repairs after the fact.

All exposed interlocking Brick Pavers and Stamped Concrete Patios require periodic maintenance to protect from sun exposure, dirt, heavy traffic from cars, and everyday spills.

General Chemical Corp. helps   protect with PaverGeneral® Paver sealer is a clear, non-yellowing acrylic sealer that will protect, seal, and enhances the natural color tones of your brick pavers or stamped concrete. PaverGeneral® Masonry Sealer will also add a "wet look".

Choosing a Masonry Sealer Depends On Where It's Used and the Desired Visual Effect

Any masonry surface can receive a sealer but most products are intended for either horizontal surfaces such as floors or vertical surfaces such as walls. Plus some products are intended for interior use only or exterior use only.
The main types of sealers available are clear penetrating coatings, pigmented coatings and film forming products. All are available in either water base or oil base formulations. Painters favor the acrylic products because the formulations allow water vapor to escape and stop liquid water .

Clear Sealers can deepen or enrich the color of the surface, but usually will not be visible. These are water sealers and are designed to repel liquid water, but they are not water proofers. Water vapor will still move through the material.

Water sealers stop liquid water from entering the surface, but allow water vapor out. They are breathable products that can be applied to brick, concrete block, stucco or any masonry material such as stone. Some are designed for use on floors, making them very useful for sealing decorative concrete stains.
Another type of clear masonry sealer is designed to combat graffiti. In this case the sealer is applied in several coats, typically 2-3. The final coat is a sacrificial coat that is pressure washed off with the graffiti. Another coat is applied after the surface has dried. This sealer forms a clear unnoticeable film.

Pigmented coatings are very similar to stains in many ways and can be water sealers or water proofers. It is possible to change the color of masonry materials and provide waterproofing at the same time. Very appropriate for renewing brick or as an alternative to paint for stucco, concrete block buildings or concrete floors.
The intensity of color can be subtle to solid. Masonry stains are similar to semi-transparent and solid color exterior wood stains. Can be applied to any masonry surface.

Film forming coatings are more like paint than a stain. They can have a sheen from satin to gloss. These products are water proofers and some can resist water pressure behind the film. This is very useful for sealing leaky basement walls. As a masonry sealer, a film-forming coating will usually last the longest.
Two examples of film forming coatings are elastomeric paint or epoxy floor coatings. This type of coating can be applied to any horizontal or vertical surface. Check the product label for recommendations as for use on floors. Not all products are suitable to be walked on.