Why is the Brick Veneer Laying on the Ground?
In the last technical post I discussed the structural basics of brick veneer: what holds it up, what holds it on, and what help does it provide.
In this post I look into why the brick veneer above fell off the wall.
The subject brick veneer was tied back to the structural wall with the most commonly used brick ties, a corrugated metal strap. My first observation is that not enough ties were installed to result in a 16 inch spacing horizontally and vertically (Figure 1). My second observation is some of the ties are deteriorated by corrosion (Figure 2). My third observation is the vertical leg of the L-shaped ties were not folded down to provide a double layer of metal before nailing. Lastly, although not a deficiency per se, the corrugated metal brick ties have a number of inherent weaknesses.
Corrugated metal brick ties are commonly fastened with one, maybe two nails, which if not driven into a solid component of the wall will pull out easily, providing no holding strength against outward movement. The corrugated ties can be easily buckled when pushed on if they span across a wider air space, providing less holding strength against inward movement. Corrugated ties corrode over time from the moisture that penetrates the brick veneer. The L-shape of the installed tie makes it susceptible to deformation when it is pulled outward, if the nail was not set relatively close to the bend in the L-shape.
The plus side of these ties is they are cheap, they are relatively easy to install, they are easily adjustable to the height of the horizontal mortar joint, they have been accepted by building departments for years, and they seem to have worked adequately for most dwellings for decades.
And now, back to the subject veneer – the brick veneer fell off as a result of the inadequate number of brick ties, the severe deterioration of those installed, and the poor installation where the vertical leg was not folded down for nailing through a double layer.