Brick Veneer Failure

Description

• The Brick Industry Association describes brick veneer as thin kiln-fired clay units that sometimes include shale, a fine-grained rock. They are between 1/2- to 1-inch thick and can be used to cover either interior or exterior walls. Brick veneers have increased in popularity since the early 1950s, possibly due to being maintenance-free. However, because brick veneer is thinner than conventional brick masonry, it can fail if not properly installed to withstand seismic loads.

Tie and Mortar Issues

• According to the FEMA Hurricane Katrina Recovery Advisory, common modes of failure stem around either the quality, placement or bonding of ties and using low-quality mortar. In the brick-laying phase of building construction, if ties are not lined up properly, they do not embed securely into the mortar joints. The anchor has a greater chance of fastener pull-out during severe, high winds.

  Also, ties could be embedded correctly; however, they can corrode due to the poor value of the tie. For example, corrugated ties frequently used in residential structures have been found not to provide adequate resistance to compressive stress as with forceful, hurricane-like high winds.

Building Code Violations

• There were no wind speed restrictions put in place prior to 1995. After that time, many failed veneer structures were found not to be in compliance with the ACI 530-05 code. The code lists specific guidelines for both rational design and prescriptive requirements with regard to wind speed limitations and area per-tie limits. In 2005, different requirements were listed in the ACI-530-05 for speeds above and below 130 mph for seismic loads caused by earthquakes, hurricanes and similar catastrophic events. Updated versions of the 530 code are produced regularly.

Improper Wall Insulation

• According to the FEMA Hurricane Katrina Recovery Advisory, when plastic foam sheathing or wood fiberboard is used rather than wood panels, collective damage can be more severe. Building occupants can be wounded when debris is propelled by wind after brick veneer fails. Pedestrians also risk serious injury when it blows off of walls and into the walkways and streets. This has been the case for brick veneer installed on both commercial and residential structures.

Prevention/Solutions

• Consider using Base and Vee or Eye and Pintle anchor ties. Compared to corrugated ties, these two-piece ties are adjustable and provide much better resistance. Avoid doubling up and installing low-grade ties that could fail due to corrosion. To help minimize injury, during the installation phase use wood panels rather than wood fiberboard or plastic foam insulation.

  Adhere to current masonry codes, specifically the latest version of the 530 Building Code Requirements & Specification for Masonry Structures by the American Concrete Institute as well as the Technical Notes on Brick Construction by the Brick Industry Association (BIA).