Is brick a good option for siding? How green is it?
The short answer is: It depends. Some bricks are greener than others. The greenest options are salvaged bricks, locally manufactured bricks with high recycled content, and adobe bricks.
Bricks do have several green attributes. They are durable, low maintenance (no painting required), fireproof, insect resistant and water resistant, and they provide thermal mass (which means they hold heat, a feature that is most helpful in regions with chilly nights or cold winters). Their small unit size also helps reduce construction scrap, and any extra brick can be used in landscaping.
The main problem with bricks is the amount of energy required to make them. The production of fired clay bricks (the type most commonly used) involves heating the bricks in kilns at very high temperatures, an energy-intensive process. (According to BuildingGreen’s GreenSpec guide, the embodied energy is 14,000 Btu per standard brick.)
If you’re going to use brick as a siding veneer, try to use salvaged or reused brick. For structural uses, salvaged brick should be tested and approved by a structural engineer. Using old bricks can create a nice historic look. With so much brick used on homes in South Carolina, there should be plenty of places near you to find used bricks. For example, Old House Salvage in Piedmont, South Carolina, has antique brick. Check the Building Materials Reuse Association’s online directory for other facilities in your area.
Your second best option is to use locally produced bricks made with recycled industrial waste. Fortunately, this material is readily available in your region. North Carolina–based Green Leaf Brick makes bricks out of 100 percent recycled materials acquired within 500 miles of their manufacturing plant. Green Leaf’s website provides a lot of information about the bricks’ green attributes. Cunningham Brick, based in Lexington, North Carolina, also uses recycled industrial waste material in its bricks; different colors have different percentages of recycled content (ranging from 7.5 to 83 percent recycled). The company's website lists multiple distributors in South Carolina.
Another alternative is to use low-fire or air-cured stabilized earth masonry (adobe brick), which has much lower embodied energy than standard fired-clay bricks (approximately 3,700 Btu per adobe brick). However, this material is better suited for homes in regions with a dry climate, such as the Southwest.
When building with brick, you can also reduce your environmental impact by using low-VOC sealers (such as AFM Safecoat's WaterShield or Penetrating WaterStop) and recycled-content mortar. Conventional mortar usually contains a lot of portland cement, which has high embodied energy. Mortar products are available that substitute industrial and agricultural waste products, such as fly ash, ground blast-furnace slag or rice-hull ash, for some of the portland cement. However, there is some controversy about whether it’s safe to incorporate potentially hazardous industrial byproducts like fly ash into construction materials.
Other green siding options include fiber cement siding, Forest Stewardship Council (FSC) certified sustainably harvested wood, natural resin–based exterior panels made of recycled materials (such as PaperStone Rainscreen XP), engineered/composition hardboard or OSB (oriented strand board), or rammed earth and stucco.
For more information:
Check the green buyer's guide in Connie McCullah's Q&A "Which is greener: fiber-cement or vinyl siding?”
See the Environmental Building News article "Residential Siding Options," for a green comparison of siding options.