CCI-Review - 2020/2021 - #2

… Elastomeric Coating—A Case Study

wall system) was non-existent. In order to implement water barriers and through-wall flashings to allow for proper drainage out of the wall cavity, very large sections of the brick masonry would need to be removed and rebuilt. Although this work would address the leaks occurring at the windows, it was an expensive solution which would still leave the building with future brick repair cycles. This building was a strong candidate for an elastomeric coating as it was a cost-effective solution which would reduce bulk water absorption from precipitation as well as address multiple other exterior wall problems.

After all the required brick repairs were completed, an elastomeric coating (chosen specifically for this building based on the vapour permeance

Figure 1: Original wall condition

Figure 2: Wall condition with Elastomeric coating applied

requirements for the wall assembly) was applied to all masonry wall areas. This solution allowed the new water resistive barrier of the wall assembly to be on the outside of the brick masonry (instead of within the wall cavity) while still allowing the wall’s internal moisture to evaporate naturally (Figure 2). The versatility and added benefit of using an elastomeric coa ting also allowed the exterior of the building to remain visually very similar to its original design, concealing all past brick repair areas resulting in a uniform, clean appearance (Photographs 1 & 2)

Since completion of the elastomeric coating application, the building has reported zero instances of water infiltration and, as an added result, has bought themselves several more years of service life out of their current windows. The money saved by eliminating future continued brick repair cycles can now also be reallocated to other capital project needs for the building.


Preventing moisture from entering our concrete and masonry buildings should be of utmost importance due to the risk of freeze/thaw damages our region is susceptible to and to prevent interior water leaks at windows and other wall penetrations. This is especially true in older buildings where barrier membranes are not effective or non-existent. Elastomeric coatings are a cost-effective solution to this problem as it essentially creates a continuous waterproof skin on the outside of the building. Elastomeric coatings also enhance the curb appeal of properties by giving walls a uniform finish and concealing unsightly past repairs or off-coloured areas of replacement bricks. Not all coatings are created equal however, and as stated earlier, choosing an incorrect type may lead to trapping moisture within the wall creating more problems instead of solving them. A building science consultant should be brought in when considering applying any coating to a building to carefully consider all the parameters before selecting the appropriate product. Since the exterior walls are only one part of a connected system which forms the complete exterior envelope, it is important to have your building science consultant review all aspects of the building. Doing so ensures all potential sources of water infiltration can be addressed to maximize the benefits and performance of any new coatings. IRC Building Sciences Group is here to help you with all your building envelope needs! If you feel your building would benefit from an elastomeric coating, we would be more than happy to discuss it with you. — BD

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