Brick Home Basics
Brick homes built prior to the 1920s are true brick homes. That is, their exterior walls are 3-4 courses of brick thick and provide the load bearing structure of the house. Homes of more recent vintage are actually of wood construction and the brick is just a single layer facade. The brick is held away from the wood construction by a 1" gap to prevent the porous brick from touching and damaging the wood structure.
Water Penetration into the Home
Brick and mortar are porous materials that quickly absorb water into them when it rains. The water gets into the brick and goes in several directions. The first direction is downward. The force of gravity causes the water to flow down. Your home should have gaps in the mortar several courses above the soil to allow this water out. Some masons will also put in a cotton cord in these gaps to let the water out. It is possible for the water to enter cracks in the foundation and show up as leaks in the basement. Or water can leak around windows and doors at it flows downward.
The second direction is inward towards the house. The brick absorbs the water from rain and if enough gets into it, the liquid water can migrate to the inside surface of the brick. If there is no gap between the brick and wood structure, it is possible for the water to damage the home by causing rot and providing insects a home.
Until the brick dries out after the rain has stopped, it is continually releasing water vapor into the home. This water vapor can also damage the structure of the home.
Sealing the Brick
Sealing the brick prevents water penetrating into it. When it rains, water will be repelled and stay out of the brick. But be sure to get the right kind of sealer. Many brick sealers are designed for patios or the interior of a home. These are not the types you want for your brick walls. Many of these have a gloss finish and sit on the surface of the brick.
A homeowner wants a non-gloss finish so that the home doesn't look like it glows in the daylight. The sealer also needs to be breathable to let out any water vapor coming out from the house.
Siloxane brick sealers penetrate up to a 1/4" below the surface of the brick. Once they are applied they are invisible to the viewer. The siloxane works by filling the microscopic pores of the brick and forming a hydrophobic barrier against water. After curing the barrier is invisible to the eye and will not yellow from UV rays. The texture of the brick will be the same as before the sealing process. Any water vapor coming out of the home's interior will still get vented. This will prevent any spalling to the brick caused by water being trapped inside and freezing in the winter.
Applying the Brick Sealer
Application of siloxane brick sealer with a pump-up garden sprayer is a fast and easy process. Begin at the bottom of the wall to prevent streaking. Be sure to read the manufacturers instructions carefully. The sealer will not harm plants but any that gets onto metal or glass should be cleaned immediately with soap and water.
