Waterproofing your brick veneer installation - Pro Masonry Guide
Waterproofing your brick veneer installation

Waterproofing your brick veneer installation

Bricks structures are not waterproof. They just aren’t. While most people think that water cannot penetrate brick, it can – and rather easily. Structures (or projects) featuring brick veneer are even more vulnerable, mainly because they are just a facade that doesn’t offer any structural support.

This is especially true when using brick veneer – a popular option that not only provides an elegant look, but also reduces costs. The installation method involves standard stick-framed walls with a veneer layer of brick over the outside walls. This results in a more time-efficient installation process.

The bottom line is that waterproofing your brick veneer installation is a necessity. Because brick veneer lacks soft inner brick, water can easily flow down the back of the single layer of brick. And if you don’t cover the wood-frame structural walls with a waterproof membrane, water will get into the wall.Left untreated (or ignored), moisture that seeps into the interior walls, especially around window frames, will begin to degrade both the appearance and performance of the brick veneer. Even worse, in colder temperatures, if the moisture within the brick freezes, it will expand, causing a “spalling” effect. Spalling causes brick to crumble and flake.


One of the best ways for waterproofing your brick veneer installation is to use flashing under the window and doorsills. Flashing is designed to collect the water that leaks through the mortar joints and redirect it to the outside of the wall.

Base flashing is also required under the first course of brick, as well as at other locations on brick veneer walls. Other materials are often placed behind the brick veneer to ensure that wet mortar falling behind the brick doesn’t block the flashings and any weep holes at the base of the brick walls.

Weep holes

Installing weep holes enables the water to flow out of the wall. It requires a significant amount of skill and attention to detail to do all the things needed to ensure a brick veneer wall does not leak. Remember to fill the holes with mortar that matches what you are using. To match mortar, you need to get sand that matches the original sand.

Closely examine the mortar joints and pay attention to the size and color of the individual grains of sand. When you mix up the new mortar, the cement paste in the mortar mix will coat all the sand, making the color of the mortar all the same shade.

Siloxane sealer

Another tip is to use a penetrating siloxane-based sealer, a waterproofing material that allows the sealant to chemically bond itself to the brick. This process enables the brick to be impenetrable against liquid water, while still allowing it to breathe. This greatly reduces the chances of spalling or any other damage to your brick veneer.

Carefully adhering to these guidelines can help ensure your brick veneer sustains the elements and provides the aesthetically appealing look you intended.

For more information, check out the Brick Industry Association PDF: Brick Veneer Construction: Basics of Resisting Water Penetration in Residential Construction

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