Compartmentalization

Technical guide to succesful multi family airsealign between dwelling units. From duplexes to large apartment buildings, the principals are same, though clearly implementation will vary a bit.

For the ‘what and why’ of compartmentalization, see this accompanying blog post.

Compartmentalization, or airsealing between dwelling units results in better homes. It results in better airquality, lower sound transmission, reduced energy transfer, and a better blower door test! Establishing a good airbarrier around all 6 sides of a multi-family unit varies in complexity based on the scale of the building, unit geometry, number of penetrations/ complexity of services , and the strategy taken. The complexity of execution also varies, depending on project team communication, experience of designers, GC and sub trades with relevant detailing and completion. Project airleakage goals and targets , either aspirational or hard (pass/fail), are also part of the equation. Through all steps here there is a spread of the ideal vs practical . Of best practice vs good enough.

1. Design in airsealing details and resources between dwelling units

The design team should integrate unit to unit and unit to hallway airbarrier detailing into the plan set in a manner that meets the project goals and is enough for the GC to execute. If the project is a 200 unit Passive House project, compartmentalization details must be extensive. But if it’s a code minimum duplex with a single party wall, detailing can be light. The point is to talk about it early. Create an environment where there is no dumb questions. Get your HERS Rater/ energy consultant involved.

There are great resources available published by Steven Winters Associates

• [guide wood framed]

• [ guide metal framed]

• recorded webinar

• stock details

We consider these resources to be like gold (big ups to SWA for making them available to all) .

However caution should exercised to not over assume all parties are looking at stock details the same way. To include them iin your plan set with out specific references is risky.

Dont confuse the interior stock airsealign details with the exterior buildign enclosure airbarrier. They may overlap, but often will be comprised of different materials. For instance, if party wall, unit to unit, airbarrier is airtight drywall. This doesn’t exftend to the exterior building walls. Their the airbarrier is more likely the sheathing or established membrane. The exterior wall sheetrock may be detailed to be a secondary airbarrier, but it is not serving the same function as the primary airbarrier.

THink in plains. If the sheetrock is the airbarrier, consider it the plane, not the material. Indeed, it’s all the space AROUND the sheetorkc that needs to be airsealed- all penetrations and seems

2. Get the team on board and identify roles and responsibilities