As today’s sustainable buildings become more resilient to withstand the effects of nature with minimal damage, energy efficient, and water- and resource-efficient, their design also addresses occupants’ wellbeing through thermal and acoustic comfort, indoor air quality and appealing aesthetics. Today’s buildings also consider the environmental impact throughout the entire life cycle, including operation and maintenance.

As an element of sustainable design, fired-clay brick can provide structure, finish, acoustic and thermal comfort, good indoor air quality, fire resistance, impact resistance and durability.

Most green building programs and rating systems often lack a means by which to promote and measure avoiding negative impacts. Brick masonry elements that perform multiple functions avoid the use of other materials, such as paints and sound insulation. Inattention to durability is another limitation to these programs. Ideally, resilient building recognizes the benefits of durable brick masonry construction with a life expectancy of hundreds of years.

Due to the aesthetic appeal, durability and historic value frequently associated with brick masonry buildings, they are often chosen for reuse. In many cases, load-bearing brick buildings are reused in their entirety, or the brick façade is retained while a new structure is built—saving resources and energy while reducing environmental impact.

Brick masonry and paving systems can help meet the requirements of many certification rating systems in rainwater management, heat island reduction, improved energy performance, acoustic performance, building reuse, materials reuse, construction waste management, recycled content and regional materials.

Flexible brick pavements can be designed as permeable pavements to allow percolation of rainwater through the pavement, thereby reducing runoff, recharging groundwater aquifers and removing contaminants from surface water.

Using materials with a three-year aged solar reflectance (SR) of 0.28 or higher on the site’s pavements and walkways or even on vegetated roofs can help reduce the heat island effect of warming building and pavement surfaces. Though lighter colors are often associated with high SR values, many brick pavers—even dark colors—can meet this requirement.

While green building codes, standards and rating systems recognize buildings for the level of sustainable design achieved through certification, consideration must also be given to how the product is manufactured, used and disposed of. To reduce construction waste, brick packaging is minimal and easily recycled. Made from abundant, natural materials—primarily clay and shale—most brick manufacturing facilities are located near the clay and shale mining sites that are often within a few miles of the manufacturing plant and within 500 miles of larger cities.

Brick units may also include recycled materials such as fly ash, and most steel reinforcement used in reinforced brick masonry has a high recycled content. For efficient material use, brick masonry walls can perform multiple functions that often require several components in other wall systems.

Recent net-zero energy projects incorporating fired-clay brick include the John W. Olver Transit Center in Greenfield, Massachusetts. The nation’s first net-zero bus station includes an 8,000 square foot photovoltaic array, 22 geothermal wells and a biomass boiler. Embedded in the building’s design are custom designed bricks and masonry patterns that embrace strategies for energy conservation: the brick cladding slows heat gain from the late afternoon summer sun. The brick screening allows filtered daylight into the interiors and lowers the use of electric lighting through daylighting.

Brick to Increase Efficiency

The top five factors of fired-clay brick that increase energy efficiency include thermal mass, air space, fixed temperature performance, varying temperature performance and a continuous insulation package.

Thermal mass offers the ability to absorb and store heat thereby slowing heat movement through the wall. As a mass product, clay brick veneer acts similarly, storing a large quantity of heat before releasing it to the cooler side of the wall that can reduce energy costs.

The air space behind brick veneer serves as an insulating layer in the wall assembly. Although the air space is connected to the outside via weeps, very little air moves in the space. Studies show that the amount of movement is negligible and can be attributed to the buoyancy of the air as it is heated, which helps explain why the air space provides so much thermal benefit. While brick ties are often blamed for causing poor thermal performance, they’re nearly undetectable by thermal imaging. The insulating and thermal storage properties of the brick and air space typically outweigh the ties’ conduction.

Energy efficiency is influenced by how the entire wall assembly—not the just the cladding material itself—reacts to temperature variations. Testing with fixed temperature conditions conducted by the National Brick Research Center (NBRC) confirms that heat takes two to three times as long to go through a brick wall assembly than it does others. The brick wall’s heat storage capacity is twice the storage capacity of the brick alone. An NBRC test with varying temperature conditions proves that brick walls reduce heat energy movement by 60% over the closest competing wall assembly. Unlike the static R-value, dynamic testing repeatedly cycles temperatures from low to high or vice versa, similar to rising and falling daytime and nighttime temperatures.

A brick veneer wall assembly combined with continuous insulation is especially beneficial in cooler, northern climates. Increasing the size of the air space allows continuous insulation to supplement the insulation between the studs. A minor increase in the width of the foundation wall will permit including continuous insulation with no change to the building’s interior space or the exterior appearance.