A masonry sealer is very different from clear wood sealers, wood stains or common house paints. All masonry components have an alkaline PH, this is opposite of wood which is slightly acidic. A high PH isn’t tolerated very well by normal house paints or wood stains.

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.