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NGBS Green Verifiers shared their experiences with verifying modular multifamily construction.

Verifier Voice: Green Verification for Modular Multifamily Buildings

October 19, 2022

Modular construction is an increasingly popular option for delivering high-quality multifamily apartments due to the quality assurance, safety, and sustainability benefits available from building in a controlled factory setting. While modular construction offers substantial quality benefits that can help a project achieve third-party green certification, there are unique verification considerations due to the rapid production schedule and coordination across factory and site installation teams. During our virtual verifier retreat in July 2021, I spoke with a panel of NGBS Green Verifiers who shared their experiences with performing verification services for modular projects and their advice for other verifiers getting started with modular projects. Here’s a summary of our conversation:

Project Background

Glenn HayduGlenn Haydu, NGBS Green Master Verifier with Minno & Wasko, provided verification services for Luna on Pine, a 5-story apartment building located in the University City neighborhood of Philadelphia. The building’s 122 units were constructed using a total of 132 modules (or boxes) that were delivered from a modular factory in Scranton, PA. Modular construction helped minimize disruption throughout the construction process, as the site is on a tight urban corner lot.

Philip LaRocquePhil LaRocque, NGBS Green Master Verifier with LaRocque Business Management Services, LLC, performed NGBS Green and ENERGY STAR rough verifications for an 80-unit, 4-story modular housing apartment community in western Virginia. The first floor of the building (20 units) was constructed on-site. The remaining 60 apartments consisting of 93 modular units were constructed at a factory in northeast PA and assembled at the project site in Virginia. Final inspections will be conducted at the project site this fall.

Jeff SlaughJeff Slaugh, NGBS Green Verifier with Energetics Consulting Engineers, LLC, provided verification services for The Confluence at Harvest Hills Apartments, a 3-story multifamily apartment building constructed in Williston, ND. The Confluence was optimized for cost-effective and quick construction to accommodate the influx of new residents due to the North Dakota oil boom. Modules were constructed in Auora, Nebraska and assembled on-site in Williston.

Factory Inspections

All three verifiers experienced quality assurance benefits from the factory construction.

Throughout the construction process, Glenn visited the factory on four different occasions. He found that factory inspection offered him a greater opportunity to inspect all sides of walls and ceilings, as all sides of the boxes were visible and everything was at eye level. As all finishes, adhesives, paints, and other materials were stored in one easily-accessible location within the factory, Glenn easily confirmed NGBS practices that require verification of product attributes. Additional quality assurance benefits were realized from the climate-controlled factory environment, consistent crew, fixed schedule, and better lighting and access compared to traditional construction.

During his factory inspections, Jeff observed that just-in-time materials ordering supported efficient material use and waste reduction. The factory featured a long-standing crew that performed repetitive assembly and installations. This approach allowed crew members to become specialists, mastering construction details that support optimal building performance. Jeff also appreciated how multiple construction phases could be completed simultaneously by the same crew. This is more efficient compared to traditional construction, where a staggered construction schedule with different construction crew can introduce the potential for errors. Like Glenn, Jeff also appreciated how the factory setting allowed him the opportunity to see all sides of a module for air sealing and other construction details. 

Phil performed five plant visits at the modular factory where he was able to view 11 units each day and inspect air sealing, insulation, window flashing, and other details. On those days, the outside weather was extremely hot and humid, but the plant workers were producing efficiently in the comfortable air-conditioned factory. A tremendous amount of material was stored and secured inside the plant; the factory team had stock-piled building materials prior to the huge lumber spikes to manage cost and protect their ability to produce in the near-term. The factory schedule proceeded like clockwork, with the units regularly shipping out to the project site ahead of schedule. (The production schedule allowed Phil to perform full verifications in accordance with the NGBS Green verification protocols.)

Site Inspections

Once the modules were installed on-site, Glenn made two separate site visits to inspect their installation and site conditions. At the tight urban site, there was no space for storage or staging of construction materials. Module deliveries were scheduled and set directly from the street. The project team ensured coordination between the factory and site work, ensuring that materials were compatible, delivered on time, and properly installed to the on-site foundation. Glenn observed that different air barrier, air sealing, and adhesive products were used at the factory and site; this added additional difficulty to verifying product-specific NGBS practices. Another complication was related to waste diversion. Waste diverted from both the factory and the site needed to be measured separately and totaled for the overall waste diversion value for NGBS compliance.

In his role as green verifier, Jeff supported coordination between factory construction and site installation. “During my factory visits, I would flag conditions for discussion during the on-site installation,” Jeff said. Jeff worked to proactively troubleshoot installation issues with the involvement of all site staff.

To minimize travel costs associated with both factory and site inspections, Phil performed factory inspections, and another NGBS Green Verifier is anticipated to perform the on-site inspections.

Quality Assurance

“Communication with all stakeholders is key to success with rough modular inspections,” said Phil. He attended initial plant meetings with all parties to ensure consistent expectations and a shared vision for sustainable design. During his initial factory visits, Phil observed inconsistencies with insulation installation and air sealing. Phil coordinated to with the site superintendent to deliver in-person training and video resources on insulation installation. Phil also prepared detailed reports with his observations and developed curative action plans to address issues identified and ensure that the project was on track to achieve NGBS Green certification. The plant had no prior experience with multifamily construction, and, based on this positive experience, the factory is in discussions to take on additional multifamily projects in the near future.

The modular factory had a rapid production schedule, often producing multiple modules per day. It was not possible for Glenn to fully inspected every module in-person, especially given the 2-hour travel required to the factory location. This necessitated Glenn to take advantage of Home Innovation’s Modular Verification Pilot Program (see page 11 of the Builder’s Resource Guide) for additional flexibility. Prior to the verification phase, Glenn submitted a verification plan for approval, which involved factory quality assurance activities and photo verification. “Establishing quality assurance and quality control expectations between the verifier and factory is critical, as they are a partner in the process. Communication is key to success,” Glenn said. 

Interested in getting started with NGBS Green Certification for your upcoming modular multifamily project? Contact these verifiers to learn more and get started! Any questions about the Modular Verification Protocol can be directed to our Green Contact form.