Location: Inman Square, Cambridge, Massachusetts
Services: PHIUS+ Energy Consulting and Mechanical Design for a New Modern Single Family Home
ZED recently visited a site in Cambridge to check out the progress of the home’s air barrier. ZED’s Jordan Goldman, who provided energy consulting and mechanical design for the three-story, single family house, led the site visit along with representatives from ZRE Development (Owner) and GRS Construction (Framer). Site visits like this during construction are important both for catching any errors before the building enclosure is complete and for educating builders about proper technique going forward in the process.
Jordan walked the interior and exterior of the home, paying particular attention to the many tricky areas where air leakage typically occurs. A home’s air barrier is intended to limit uncontrolled air leakage into and out of a building’s thermal envelope. ZED’s design is for the air barrier to be continuous, which means that the system has no discontinuities, particularly as it transitions from one assembly to another (e.g. from wall to roof). ZED typically installs the air barrier at the sheathing layer, where it’s easy to maintain continuity across the envelope. Exterior rigid insulation will protect the air barrier from the outside and the framed wall cavity protects the air barrier from meddling hands on the inside.
Example of an air barrier:
Thermal Envelope:
The basement slab, foundation walls, above-grade walls, ceilings, roofs and any other building element assemblies that enclose conditioned space or provide a boundary between conditioned space and outdoors or uninsulated spaces.
The largest component of this Cambridge home’s air barrier is the green ZIP System sheathing that wraps the whole exterior of the house, but there are other components that we will explore below: