Why you need an air gap between your cladding and your WRB
I recently talked to Karl Wages, a builder from Irvington, Alabama, who is repairing a brick-veneer building with a water entry problem.
The mason failed to maintain the required air gap between the brick veneer and the WRB. At this building, the WRB was a single layer of Dow Weathermate housewrap. After just a few years, the housewrap deteriorated — probably because the damp mortar is alkaline, and the mortar was touching the housewrap.
Karl sent me the photo below.
There are many lessons here:
1. If possible, keep on eye on your mason’s work.
2. Only hire masons whose work you trust.
3. One layer of WRB behind brick veneer is risky; two are better. In most cases, the best material behind brick veneer is a layer of rigid foam.
4. Always maintain an air gap between the brick veneer and the WRB.