ByJorge Casuso

April 25, 2024 -- The City Council on Tuesday literally took a concrete step to fight carbon emissions by requiring the use of low-carbon concrete for all new construction, swimming pools and spas.

The switch from traditional concrete will reduce carbon emissions from the building sector, which accounts for 26 percent of greenhouse gas emissions, according to a report to the Council from the City's Office of Sustainability and the Environment (OSE).

The ordinance amends the building code to effectively eliminate the use of cement -- which is "carbon-intensive" to produce -- and replace it with alternative materials in making concrete, OSE staff wrote.

According to industry sources, alternative materials include mineral compounds such as fly ash, blast-furnace slag and calcined clays that, unlike cement, do not require large amounts of energy to produce.

The switch could reduce the carbon emissions from the manufacturing and transportation of building materials by 14 to 33 percent without increasing building costs, according to staff.

"New construction buildings offer a major opportunity to mitigate future emissions given the long-term nature of a building as an asset," staff wrote.

"Low-carbon concrete requirements provide an opportunity to drastically reduce future carbon emissions."

While the City's Climate Action and Adaptation Plan sets goals for emissions from the operation of a building, it does not account for "embodied" carbon emissions, staff said.

After researching possible policies, OSE staff found that a low-carbon concrete policy "is the most effective, efficient, and direct pathway to reduce embodied carbon emissions without increasing costs for developers or the City."

In drafting the ordinance, staff sought input from local concrete suppliers and builders.

"All expressed support and readiness to provide low-carbon concrete options," according to the staff report. "These options are readily available now and often at a lower cost than traditional cement."

The City already uses low-carbon concrete mixes in municipal infrastructure projects, including the Moongate structure at Woodlawn Cemetery.

Among the major buildings that have used low-carbon concrete materials are the Wilshire Grand Center in downtown Los Angeles and the One World Trade Center in New York, which is the tallest building in the Western Hemisphere.

The ordinance makes exemptions if the cost of low-carbon options is higher than that of traditional concrete mix or if it is not commercially available.

It also exempts projects that require less than three yards of pre-packaged concrete bags and during emergencies.

Compliance checks for the new ordinance will be part of the Plan Check process.

With Tuesday's vote, Santa Monica joins Marin County and Palo Alto "as leaders in the State and country in reducing embodied carbon emissions from concrete without raising the cost of construction," staff said.

The ordinance will return to the Council for a second reading on May 14 and go into effect 30 days later.