Do third-party green building inspections actually add value to projects? A recent study by SK Collaborative set out to answer this question by analyzing 10 recently constructed or renovated multifamily affordable housing projects in Georgia, all of which received Low-Income Housing Tax Credit (LIHTC)
The ICC-700 National Green Building Standard® (NGBS)
, like most other voluntary green building programs, requires third-party verification for certification. These inspections typically happen mid-construction, immediately following insulation, and again when construction is substantially complete. Half of the projects that the team analyzed pursued green building certification, and half elected to only meet the state Qualified Allocation Plan (QAP) prescriptive requirements for duct and envelope tightness and required sustainability items.
The results provide insight on the importance of green certification third-party inspections.
Assumptions and Limitations
Green building certification is a process that begins long before the first site inspection. Projects undergo a design review meeting with the primary development and construction team, a construction kickoff meeting with all key contractors, and detailed plan and construction specification reviews before a green verifier ever steps foot on a project site. Issues identified prior to inspection, either through document review or project team meetings, were not included in SK Collective's analysis.
The analysis did, however, identify a number of deficiencies and failures uncovered during the inspection process, which have been grouped by type. For example, insulation failures were counted as one item, even though there may have been multiple insulation-related problems in a single project. Builders and trade contractors are typically present during the inspection, allowing them to make corrections identified during site visits. These issues may be remediated on site, and do not show up as failures on the inspection reports or in the results included here.
Projects Seeking Green Building Certification
Of the five projects that opted for green certification, the programs selected included NGBS, Enterprise Green Communities and EarthCraft Multifamily. On average, seven failures were found at the first mid-construction inspection and six failures at the initial final inspection.
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Figure 1: Poorly maintained silt fencing around the perimeter of a construction site[/caption]
Many of the issues were also building code failures overlooked by local officials, such as missing or incomplete envelope air sealing and poorly installed or completely missing insulation. These items are required by International Residential Code (IRC), International Fire Code (IFC) and International Energy Conservation Code (IECC). Some projects had incomplete duct sealing and excessive duct leakage. Projects were also frequently in violation of Georgia sedimentation and erosion control requirements, which are enforced by green building programs (Figure 1).
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Figure 2: An inspector measuring the air flow of an in-wall bath exhaust fan.[/caption]
Green building program-specific failures included poorly installed HVAC ductwork (excessive bends and crimps), non-specified HVAC filter installed, no rodent or pest screens over ventilation openings, and missing dampers on bath exhaust ductwork (Figure 2).
Projects Not Seeking Green Building Certification
For the new construction projects, the QAP required minimum energy code compliance and a short list of prescriptive sustainability measures, such as ENERGY STAR-qualified bath exhaust fans. Figure 3 shows unsealed penetrations through the top plate. The new construction projects had an average of three failures at mid-construction and one at final.
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Figure 3: Unsealed penetrations through the top plate[/caption]
For the renovation projects, the applicable QAP required compliance with the energy code for new construction or achieving a 20% percent reduction in duct and/or envelope leakage. The renovation projects had an average of two failures at mid-construction and one at final.
Third-Party Inspections Can Eliminate Long-Term Issues
Projects pursuing green building certification had more failures, but that's not surprising as there are significantly more compliance items. What's not as obvious in the data is that the projects seeking green building certification tended to have a much smoother path to compliance.
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Figure 4: Poorly installed fiberglass batts[/caption]
All projects struggled with basic energy code requirements such as properly installed insulation and air sealing (Figure 4). If these failures had remained, residents would likely have experienced higher utility bills in less comfortable homes. Property management and owners would likely have faced maintenance problems and resident complaints.
For all of these projects, third-party verification was a critical piece in finding and addressing these issues before project completion, thereby avoiding long-term problems that would have had a direct impact on residents.
Abe Kruger honed his expertise in sustainable construction over the last 16 years as a contractor, educator and consultant in the construction industry. He is the cofounder of SK Collaborative, which provides green building, healthy housing and building envelope consulting. SK Collaborative is currently certifying more than 20,000 units of single- and multifamily housing across the country.