GYPSUM BOARD

Carbon Impact of Gypsum Board

Gypsum board (sometimes referred to as plasterboard or drywall) is a commonly used building finish material for walls, ceilings, and partitions, in part due to its inherent fire resistance. About 2 billion m² (25 billion ft²) of gypsum board is manufactured annually¹ using about 23 million tonnes (25 million tons) of crude and synthetic gypsum². The gypsum used in gypsum board comes from both natural (mined) and synthetic sources. Synthetic, or Flue Gas Desulphurization (FGD) gypsum, is a by-product of coal-fired power plants³.

Gypsum board is an energy intensive product to manufacture. According to an Industry Average EPD, every 93 board meters (1,000 board feet) of drywall produced requires about 5,048 MJ of non-renewable primary energy (electricity and natural gas usage)⁴.

There is a significant amount of gypsum board waste disposal – it is estimated that 300,000 tonnes (330,700 tons) per year of gypsum board waste from new construction alone are generated as a result of over-ordering, incorrect specification, damage, and off-cuts during construction³. While gypsum board is easy to recycle, finding recycling facilities for gypsum board can be difficult.

The paper exteriors and gypsum cores of gypsum board can be made from high percentages of recycled material, but this results in limited to no energy savings because it must go through the manufacturing process again.

Some manufacturers are reducing carbon emissions from gypsum board by reducing the amount of water used in the mix and hence the amount of heat, and associated emissions, needed to dry the mix. This results in a lightweight product that also cuts down on transportation emissions.

Specifying lightweight gypsum board products and eliminating waste material are the most impactful ways to reduce the carbon footprint of gypsum board.

Carbon Smart Attributes

Specify lightweight gypsum board

Lighter weight gypsum board requires less water during the manufacturing process which results in lower drying energy and lower carbon emissions. Specify lightweight gypsum board products, which have 25-30% less weight than standard gypsum board. These products can also significantly reduce carbon emissions from transportation.

Use the thinnest gypsum board necessary

Gypsum board thicknesses vary from ¼ to ¾ inches, in ⅛-inch increments⁵. Use the minimum thickness needed in order to reduce the amount of material being used.

Design & Construction Guidance

Consider lower embodied carbon panel products where appropriate

Gypsum board alternatives that utilize compressed agricultural fibers (CAF) may present a low-carbon alternative to standard gypsum board. Where code allows, look for products that utilize agricultural waste, such as wheat, rice, and straw byproduct, which sequester carbon during their growth and store that carbon as a building product. These products often require less energy-intensive manufacturing processes, but may not provide the required fire resistant properties that gypsum board does and may require additional fire suppression systems. Environmental Product Declarations (EPDs) are now available for most panel products allowing users to compare the embodied carbon values of similarly functioning panel products.

Where gypsum board is needed, design to eliminate waste

Designing for deconstruction and designing to minimize waste helps to reduce emissions associated with wasted material, such as landfill emissions and emissions associated with the production of new or replacement material. The following design and construction guidance helps to eliminate waste:

Use fewer different grades and sizes

Specifying multiple types of gypsum board for a project often increases construction waste, in part because some types of gypsum board cannot be recycled together³. Specify fewer different grades and sizes to allow for recycling.

Understand standard gypsum board product sizes and draw each board in design

Gypsum board is available in a variety of standard sizes, though 4 ft wide by 8 ft high is the most common. When designing, draw each board and work out the most efficient combination to reduce off-cutting waste.

Design for deconstruction

Using battens or dry joints can allow for the deconstruction and reuse of gypsum boards. Specify partitions that can be disassembled and reused where possible.

Protect gypsum board from water, moisture, and extreme temperatures

Standard gypsum products must be protected before, during and after construction in order to ensure the longevity of the product, as standard gypsum products are not durable in moisture-exposed applications. When risk of moisture exposure is present, choose products and systems that offer adequate resistance. In areas prone to flooding, use solid wall construction instead.

Identify recycling locations for gypsum board waste

Gypsum board can be recycled into new gypsum products. First design out as much waste as possible, then identify locations to recycle any remaining gypsum board waste.

Reference Whole Building Approaches – Design for Flexibility and Future Adaptation – design interior partitions that can be moved and interior spaces that are flexible enough that they don’t need to be torn down and built out when a building changes ownership.

Acknowledged Challenges, Questions & Unknowns:

Future innovation

While not yet being used in practice, innovations in manufacturing technology are allowing manufacturers to convert factories to use solar technology rather than natural gas for process heat, significantly reducing manufacturing carbon emissions.