9N85 Brown Tweed, Closure Size

9N85 Brown Tweed, Closure Size

9N85 Brown Tweed, Closure Size

1S79 New Used, Standard Size

1S79 New Used, Standard Size

1S79 New Used, Standard Size

1S39 Oxford, Standard Size

1S39 Oxford, Standard Size

1S39 Oxford, Standard Size

9S60 Standford, Closure Size

9S60 Standford, Closure Size

9S60 Standford, Closure Size

9N82 Soulard Tudor, Closure Size

9N82 Soulard Tudor, Closure Size

9N82 Soulard Tudor, Closure Size

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Why Brick is the Best Wall Cladding Material to Control Building Envelope Moisture

Bricks in rain.Moisture issues have become an increasing concern in residential construction.  While builders address growing demands for occupant comfort and energy-efficiency, modern construction practices have resulted in tight walls that are highly insulated and sealed against air filtration. 

When moisture is not sufficiently controlled with these lighter, tighter building  methods, the risk of mold growth, wood rot, infestation by insects, reduced efficiency of insulation, and corrosion of fasteners embedded in wood all increase dramatically.  Consequently, proper specification of materials and building practices not only impacts a home's value at the point of sale (and resale), but it also impacts your long-term reputation as a quality builder.

To help provide an understanding of how wall cladding materials and systems perform over a period of time, the NAHB Research Center, wholly-owned subsidiary of the National Association of Home Builders, recently completed a year-long field moisture study entitled "Moisture Performance Comparison of Typical Residential Wall Assemblies."  The projects objective was to determine how exterior cladding can impact the moisture content of the wooden components in the wall construction.

The field study, which was conducted in a mixed-humid climate 20 miles east of Washington D.C., was designed to collect moisture performance values at regular intervals from key components within a pair of wall assemblies constructed with each of eight different cladding types.  Weather conditions over the test period were near 30-year historical average conditions of the area with the exception of a somewhat milder summer and 5% less rainfall.  Each wall assembly consisted of interior gypsum board and wood studs with fiberglass insulation between the studs.  This assembly was sheathed with either oriented strand board or plywood and clad with brick veneer, vinyl siding, fiber cement siding, manufactured stone, or stucco.

Each wall assembly was then subjected to ambient weather conditions over a one-year period.  In addition, a portion of the water-resistive barrier was compromised, and the wall assembly behind it was subjected to a daily water injection over a five-day period to evaluate its ability to dry after a leak.  The data recorded for each wall assembly included wood stud moisture content, wood-based sheathing moisture content, stud bay relative humidity, and stud bay temperature.  

What Were The Results?

The studs in the brick wall assembly had the lowest moisture content overall in both north and south exposures.  Also, the wood-based sheathing of the south facing brick wall assembly was drier than any other wall assembly tested.  While in all of the tested assemblies the wood studs and wood-based sheathings were below 16% moisture content under normal conditions, the walls with brick veneer performed significantly better overall.  The report attributes the lower moisture content in the wood components to brick's inherent thermal mass properties, the one-inch air space in the brick veneer wall, and the increased thermal absorptance of the test brick due to its red color. 

What Does This Mean for Architects & Builders?

Architects and builders have another reason to choose brick if they wish to provide their customers the protections of a superior wall system that customers want, instead of one that merely meets minimal thresholds.  Clay brick is made from naturally abundant materials, and brick's thermal mass properties promote energy efficiency because of its ability to absorb and retain heat to release at a later time.  Combined with brick's superior performance, you owe it to your customers and your reputation by building with brick.

This article was reprinted from the BIA's Builder Notes, Why Brick is the Best Wall Cladding Material to Control Building Envelope Moisture (PDF). Please click the link to view the full Builder Note.