Nudura® Insulated Concrete Form (ICF) Construction Delivers Quieter Spaces for Urban Living at Multi-use Development, 21 Summer Street, Natick Massachusetts
Architects: Main Street Architects, Weymouth, Massachusetts
Developer: Stonegate Group, Natick, Massachusetts
General Contractor: PointsNorth Construction Management LLC
Concrete Installer: Key Industries, New Ipswich, New Hampshire
ICF construction with Nudura® forms was used to control sound intrusion and improve energy efficiency in the multi-use property redevelopment of 21 Summer Street in Natick, Massachusetts. The project meets the parameters of the Massachusetts Bay Transit Authority (MBTA) Multifamily Zoning Requirement.
In 2021, Massachusetts enacted the MBTA Communities Zoning Law which requires that multifamily housing be included in communities within a half-mile of transit and other transportation facilities. The goal is not only to provide housing to address a nationwide shortage, but also to provide homes in areas where transportation is readily available, resulting in the use of fewer single-occupant vehicles. One of the challenges of building residential projects in urban locations is the transmission of noise from the surrounding community into living spaces. Atlantic Builders Supply Northeast works with contractors to provide an ICF solution for mitigating urban noise, creating quiet, desirable living spaces for those in MBTA communities.
ICF construction combines a concrete core surrounded by expanded polystyrene (EPS) foam in a wall system that reduces sound transmission. Sound transmission testing, expressed as the sound transmission class (STC) may be accessed at https://atlanticbuilderssupply.com/why-icf#reduced-sound. In addition to enhanced energy performance and reduced sound transmission, the concrete combined with the EPS forms serve as both a vapor barrier and an air barrier. The additional advantage is that insulation, moisture control, and sound mitigation are all achieved in one step when using Nudura forms.
These quieter spaces provide a refuge even in highly trafficked urban areas. The typical STC rating for wood-framed structures is 38, while the combination of concrete mass and insulating EPS can provide a STC rating in excess of 52, which is the equivalent of loud sounds being heard faintly or not at all.
The project was not originally designed for ICF construction. Subcontractor Key Industries suggested ICF as a means to reduce energy costs and mitigate sound intrusion within the residential units. Atlantic Builders Supply worked with the ICF installer to select Nudura® ICF forms that would provide a combination of reduction in sound transmission and exceptional energy performance. The thermal mass achievable with ICF structures improves energy efficiency, making it possible to easily accommodate strict energy codes. The Massachusetts energy code falls in line behind California and New York as the strictest energy codes in the United States. Dense concrete cores enhance energy performance, while the integrated EPS greatly reduces sound transmission. Nudura ICF forms can achieve an R-value 58% greater than a 2” x 6” wood frame wall with a lower life cycle assessment than timber frame construction.
The continuous insulating properties and concrete components of ICF construction mean buildings maintain a comfortable interior environment, no matter what the temperature is outside. Higher thermal resistance, superior R-values and elimination of air infiltration through ICF construction translates to lower costs to heat and cool, saving building owners up to 60% in annual energy costs.
The 21 Summer Street development is located on the site of a former craft brewery. The previous one-story structure has been replaced by four stories that house retail and other commercial tenants, with 13 rental units above. The rental units comply with MBTA zoning with no age restrictions and units that are suitable for families with children.