Building a Culture of


25 MWs thru solar
& cogeneration

Millions of gallons
wastewater cleaned

100% solar powered
HQ & yard

Certified Staff

How does Overaa recycle plywood and lumber?

How does Overaa recycle concrete, steel and asphalt?

Our Corporate Responsibility

As general contractors, our actions and decisions have a big impact on both our local community and the environment. Corporate Responsibility is the process of integrating environmental, social, and governance (ESG) considerations into our everyday operations, initiatives, and policies.

At Overaa, we are committed to aligning our work with effective, measurable strategic goals. Our strategy is aimed at assessing our company’s positive actions via quantifiable metrics.

Environmental Strategy

As builders of structures that will stand for generations, we want our buildings to have a positive impact for decades to come. We commit to an integrated decision making approach in planning, material sourcing, and construction that considers various measured strategies into the equation.

For every project or initiative, it is our responsibility to decrease our material waste, reduce our carbon emissions, and source clean energy for operations. Our ESG Environmental Strategy is aimed at assessing our actions via quantifiable metrics, with the following six categories:

  1. Carbon Emissions
  2. Material Waste Management
  3. Water Management
  4. Transportation
  5. Community Impact
  6. Project Selections

Net Zero Certification

leed Certification

1. Carbon Emissions


Establish a corporate carbon commitment and metrics.

  1. Integrate Embodied Carbon Calculator (EC3) and make informed procurement selections based on low carbon emissions.
  2. Collect Environmental Product Declarations (EPD) for materials used.
  3. Partner with suppliers to increase cement replacement alternatives in concrete mixes.
  4. Increase usage of solar power or other renewable energy sources at jobsites, prefabrication sites, and offices.

2. Material Waste Management


Restructure Waste Management approach for optimized landfill diversion and transparency.

  1. Reduce total waste generated on jobsites.
  2. Increase usage of reusable formwork.
    • Aggregate forming operations in centralized locations to facilitate reuse. 
    • Invest in reusable aluminum and steel formwork.
  3. Increase centralized and prefabrication operations where viable.
  4. Increase number of projects certified with TRUE Zero Waste program. (Certified projects divert 90% from landfill.)
  5. Utilize Recycling Certification Institute (RCI) facilities for mixed construction and demolition.

3. Water Management


Reduce virtual water consumption (water consumed during construction projects.)

  1. Increase usage of rainwater harvesting, greywater recycling systems.
  2. Use water metering through smart irrigation systems, pressure-reducing valves.
  3. Use water-efficient toilets, decrease usage of plastic single use drinking water bottles

4. Transportation


Decarbonize corporate transportation, travel, and equipment.

  1. Decrease diesel and gas powered vehicles and equipment in corporate fleet. Increase fleet of EV/Hybrid trucks and vehicles.
  2. Encourage telecommuting options where appropriate.
  3. Increase public transportation benefits for employees.
  4. Increase number of carpool vehicles and increase carpooling benefits for employees.

Recycled Water

paRKSMART Certification

decarbonize Transportation

Community engagement

5. Community Impact


Expand collaboration, training, and participation of Green Team.

  1. Increase participation and engagement in LEED (Leadership in Energy and Environmental Design) and SWPPP (Stormwater Pollution Prevention Plan) training.
  2. Understand and commit to new San Francisco and California State Climate change policies, including:
    • Design for All Electric Buildings ahead of upcoming California mandate.
    • Buy Clean California Act (BCCA) Meet targets for GWP (Global Warming Potential) for Structural Steel, Rebar, Flat Glass, Board Insulation by 1/1/2022.
    • Architecture 2030 Challenge Reduce embodied carbon emissions from all new buildings, infrastructure, and associated materials by 65% by 2030 and zero by 2040.
    • SB 100 100% Clean Energy Act: California to be powered by carbon-free electricity by 2045.

6. Project Selection


Seek projects that help the environment and align with partners that share our values.

  1. Seek out water purification, water recycling, material recycling, and green energy generation projects such as solar, cogeneration, and biofuel.
  2. Seek out LEED projects, ParkSmart projects, and other certified green building projects.

How we're doing


Overaa invests in equipment and material that can be reused multiple times, such as these Cunningham beams that are used in horizontal deck forming applications. The are collapsible for transport and storage.


Choosing materials that promote reuse and decrease emissions


Finding efficiencies in forming operations and concrete purchases

Concrete related activities represent 55% of our work volume, so a primary focus is on material, equipment and processes used in concrete forming operations. Overaa buys approximately 75,000 cubic yards of concrete, 132,000 board feet of milled lumber, and 195,000 board feet of forming plywood annually. That’s a lot of raw natural resources. Most of the wood is cut and assembled into forming panels at Overaa’s fabrication yard in Richmond then dispatched to various jobsites.

We partner with concrete suppliers who help us use low emission admixture designs and we are tracking our annual concrete usage so we can work toward reducing our overall carbon footprint and global warming potential (GWP).

Environmental projects

Many of our projects involve water purification, material recycling, and green energy generation, such as the Miners Ranch Water Treatment Plant Improvement project, a progressive design build project that expanded plant capacity from 14 to 21 million gallons per day of clean water to serve approximately 6,700 households in Butte County.


Choosing projects and partners that align with our values


Choosing projects that support the environmental initiatives

Overaa actively pursues projects that include water purification, water recycling, material recycling, and green energy generation such as solar, cogeneration, and biofuel. 

In 2009, Overaa invested in people and equipment to increase our ability to compete in the water resource and municipal infrastructure market. Today, more than half of our volume of work involves water resource management, material resource management, and renewable energy. We have been named one of the Top Environmental Firms in the nation three years in a row by Engineering News Record (ENR).

Additionally, we seek out LEED projects, Net Zero projects, ParkSmart projects, and other certified green building projects. In 2018, we built the world’s first rotating laboratory, The FLEXLab at Lawrence Berkeley National Labs, to support research in building system efficiency such as building envelopes, windows, and ventilation, and energy control systems.

We recently built the largest commercial kitchen in Northern California, the Central Commissary, for  Oakland Unified School District. That project was named a Top Environmental Project Merit Award by ENR in 2021. The project uses 35% less electricity than comparable structures thanks to extensive daylighting, carbon dioxide-based refrigeration, waste heat recapture system, and full building systems integration.

100% SOLAR Headquarters

Since 2016, Overaa has invested in renewable energy to power operations.


100% Solar Powered, Centralized Operations


Going green 

Our Richmond headquarters – including our prefabrication yard and shop – is 100% solar powered

In 2016, we added our first solar array to our rooftop and in 2018, we added an additional 5,852 SF carport structure equipped with solar panels. Together, the system produces approximately 194,151 KW per year of energy, enough to power our offices, shop, and prefabrication yard most days of the year. On days that this is not enough, we source our supplemental energy from MCE Solar One, a 10.5 megawatt solar farm that Overaa helped build in 2018 (we designed and built the concrete pedestals for the solar panels.)

The energy generated from Overaa’s solar system is equivalent to 137 metric tons of carbon dioxide emissions avoided. This is equal to 23.9 homes’ electricity use in one year, removing 29.1 passenger vehicles from the road each year, or the carbon sequestered by 162 acres of US forest in one year.

decreasing waste

Prefabrication, centralized operations, and a robust waste management program help us reuse and recycle building materials.


Choosing methods that promote reuse, decrease waste, and lower emissions


Finding efficiencies in centralized forming operations and prefabrication

  • Our centralized prefabrication location lets us save wood remnants for other applications and utilize 95% of the original purchased material. 
  • We use aluminum and steel forms that can be reused up to 250 times wherever possible. 
  • We invest in laminated veneered lumber (LVL) which uses the remnants of milled lumber and dismantle prefabricated wood “I” joists to reuse the components in other forming material. 
  • We replace high strength steel, re-useable wall forming ties in 85% of our wall forming applications, thereby replacing one-time use steel snap ties with plastic cones. 
  • Recycled plastic nailers are used in place of wood nailers in aluminum joists. 
  • We encourage the use of recycled Class II aggregate subbase in 92% of our subgrade preparation work.

sustainable Stewardship

Most of our clients are interested in investigating methods and materials that can lower the impact of construction on natural resources and carbon emissions. Our in house team provides thoughtful analysis and options.


Certified Green Building Specialists


Education, training and engagement in the newest approaches to sustainability

Overaa LEED certified professionals get involved with design teams early in the development phase to help analyze materials and methods and to incorporate concepts to achieve LEED accreditation. From our knowledge base, we provide critical value analysis for project teams to make strategic decisions during the project development.  

We also have Stormwater Pollution Prevention Plan (SWPPP) certified staff, ready to help you implement and maintain your project’s SWPPP that was developed during design. Our comprehensive SWPPP services cover: regulatory compliance and compatibility and feasibility for both construction as well as industrial general permits. 

In addition to LEED, our team uses benchmark systems to validate sustainable design approach for our projects including Living Building Challenge, ParkSmart, CHPS, Labs 21, SITES, Well Building Standard, Buy Clean California Act, Architecture 2030, SB 100 etc.