Sustainability Report

The 4Roots Education Building employs several strategies to reduce its embodied carbon:

• Mass Timber Construction: Features locally sourced southern yellow pine glulam beams and columns, as well as cross-laminated timber (CLT) walls and roof decks. Mass timber structures inherently sequester carbon, actively decreasing the project’s carbon footprint.

• Reduced Material Use (Exposed Timber): By exposing and embracing the mass timber walls and structure as finished products, the need for additional finish materials and their associated embodied carbon is reduced.

• Fiber Cement Wall Panels: Utilizes fiber cement panels, which are described as a low-carbon construction material that is also red-list free, recyclable, and durable. This material choice allowed for a large reduction in embodied carbon compared to CMU wall assemblies.

• Site-Milled Cypress: Existing cypress trees on site were harvested before construction and repurposed to create millwork and interior paneling, eliminating the embodied carbon associated with new material production and transportation for these elements.

• Local Materials Sourcing: All products were sourced within 310 miles, significantly minimizing embodied carbon from transportation. This regional sourcing strategy allows the structure to sequester atmospheric carbon rather than emit it through long-distance shipping.

• Waste Management Plan: A disciplined, closely monitored waste management plan ensured minimal waste was sent to landfills, with all reusable materials redirected accordingly, thereby reducing the embodied carbon of discarded materials. The installation process also focused on reducing waste.

• Material Transparency Standard: Materials were chosen based on their performance and carbon impact, guided by Little's Materials Transparency Standard, emphasizing understanding of material life cycle, sourcing, and carbon sequestration potential.

The 4Roots Education Building demonstrates strong operational emissions/energy performance through:

• Zero Carbon Certification: The building is pursuing the Living Building Challenge Zero Carbon Certification.

• Solar Harvesting: A large 84.2 kW solar panel array on the roof is designed to offset a minimum of 168% of the building's electrical demand (22 EUI), providing excess energy to the surrounding community’s energy grid and significantly reducing reliance on fossil fuels.

• Reduced Energy Use Intensity (EUI): The building operates at an EUI of 22 kBtu/sf/yr, a significant reduction compared to a typical building of its size (baseline EUI of 65 kBtu/sf/yr), demonstrating it generates 2.5 times its energy needs.

• Building Envelope Efficiency: The envelope significantly reduces air infiltration and exfiltration, resulting in a measured air leakage of 0.13 CFM, which is 68% tighter than code requirements. This efficiency eliminates the need for oversized mechanical systems.

• Efficient HVAC System: High-efficiency variable air volume Air-Handling Units with Energy Recovery Ventilators optimize energy use.

• Building Automation System (BAS): Utilizes BAS for reset strategies and sequences to optimize energy use of systems.

• Optimized Glazing Systems/Glare Control: Electrochromatic glazing systems on windows reduce glare while harvesting daylight and aiding temperature control, minimizing cooling needs. Overhangs provide additional shading.

• Efficient Lighting: Features LED fixtures throughout, contributing to an efficient Lighting Power Density.

• Daylight Harvesting: A whole building average of Spatial Daylight Autonomy (SDA) is 98%, far exceeding the target of greater than 50%, ensuring plentiful natural light and reducing energy for artificial lighting. Skylights and operable windows further enhance daylighting and cross-ventilation.

• Minimized Glare/Heat Gain: The whole building average of Annual Sunlight Exposure (ASE) is only 13%, indicating minimal areas receive excessive direct sunlight, helping to control heat gain passively.

The project integrates strategies that reduce long-term service and maintenance emissions:

• Durable Materials: Use of mass timber (glulam, CLT) and fiber cement wall panels, which are described as durable and long-lasting, implies reduced need for frequent replacement or repair.

• Pest-Resistant Materials: Fiber cement panels are noted as pest-resistant, which can reduce maintenance needs related to pest control.

• Material Transparency Standard: The rigorous material selection process, which considers material life cycle and performance, inherently leads to choices that promote longevity and reduce future maintenance.

• Rainwater Harvesting and Condensate Reclamation: Capturing and reusing non-potable water for toilet flushing and irrigation (up to 4,000 gallons) reduces the energy and carbon footprint associated with municipal water treatment and pumping for these uses, lessening the service burden on infrastructure.

• Permaculture and Native Landscaping: Irrigating permaculture landscaping with harvested rainwater and using native plant species reduces ongoing irrigation maintenance and associated resources.

• Resilience to Climate Events: The building is built above the 100-year floodplain with a protective curb for the mass timber, and has withstood multiple hurricanes without damage. This resilience significantly reduces the need for repairs and rebuilding after extreme weather events, minimizing future maintenance and associated emissions. Limited impermeable surfaces and adaptive landscape design also support this resilience.