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Leaks in Commercial & Industrial Masonry Walls

March 16, 2020

There are several reasons why masonry walls might leak. One source is holes in exterior walls caused by failure to properly seal abandoned pipes (old gas and water lines, conduit, HVAC, etc.). Another source can be cracks in masonry walls and gaps in mortar joints as a result of aged/deteriorated mortar. Leaks in exterior masonry walls can also be the result of misguided building maintenance efforts to stop leaks by sealing weep holes. However, the most difficult problem to address that often causes masonry walls to leak is faulty installation of through-wall flashing. Let’s look a little deeper into some of these factors and define some of these terms for additional perspective:

Weeps are the gaps left between some bricks in exterior masonry walls. Sometimes referred to as weep holes, they are part of the drainage system for exterior masonry walls and must remain open and clear. They serve two very important purposes:

  1. Weeps provide ventilation of the internal wall cavity - without proper ventilation, mildew, dry-rot and damage will reduce the life of internal wall components.
  2. Weeps allow any water entering a masonry wall a route to “escape” to the exterior. Without weeps, water will build-up inside the internal wall cavity, leading to interior leaks and other problems. Without weeps, through-wall flashings would serve, effectively, as a gutter without downspouts.

Through-wall (thru-wall) flashing is above-grade waterproofing. It protects specific areas within exterior wall assemblies and creates an impervious barrier for water to follow to the face of the exterior masonry wall. Through-wall flashing protects areas within the exterior wall assembly, including:

  • The face of the “blocking” wall to the face of the exterior masonry wall
  • The innermost part of a window sill, window head and sides of window
  • Door thresholds and steel lintels

Deciding on procedures to repair leaks in masonry walls can be tricky. Possible repairs include repointing and/or application of a water repellant clear coating.

If the source of the leaks is determined to be faulty, poorly-installed through-wall flashing, a systematic method of brick removal, followed by removal of faulty flashing and installation of new through-wall flashing will likely be required and is an expensive undertaking.

In the case of water repellant clear coating, the exterior masonry must be cleaned using a pressure-washer with eco-friendly chemicals. Also, repointing may be required before the water repellent is applied. Repointing is a method of placing wet mortar into the “raked-cleaned” existing mortar joints to repair weathered joints in old masonry. Repointing is also commonly referred to as tuckpointing.

Annual inspection of building envelope (a building’s roof, walls and windows) penetrations is part of a solid maintenance program for your building and will help you identify potential faults before they become problems. Always use experienced professionals when undertaking building maintenance. For information on our building maintenance program, contact the following representatives.

Huntsville Office: Eric Crawford ecrawford@standardexteriorsolutions.com
Birmingham Office: Derrick Burnett djburnett@standardexteriorsolutions.com 
Montgomery Office: Dwayne Burnett dburnett@standardexteriorsolutions.com 
Donny Cook dcook@standardexteriorsolutions.com 

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