At A Glance
- How Halo Interra creates a continuous roof air barrier
- Insulation strategy combining rigid board and blown-in cellulose
- How simple geometry supports airtight performance
- Layered sealing strategies at roof-to-wall transitions
Performance doesn’t stop at the walls. It continues—right to the roof.
Because in high-performance construction, the roof assembly isn’t just about covering the structure. It’s about maintaining airtightness, controlling heat loss, and connecting every layer back to a continuous system.
In this phase of the build, Dennis Borren walks through how the roof assembly was detailed to maintain performance from wall to ceiling—without introducing weak points.
You can continue reading below, or watch the interview segment to hear Dennis walk through these details in his own words.
What material serves as the air control layer in the roof or ceiling assembly, and how is its continuity ensured throughout the assembly?
For this project, the air control layer at the roof connection is Halo Interra.
An inch and a half of Halo Interra was installed, with all joints taped to provide an airtight seal. That layer is then connected directly to the ICF concrete core.
At the top plate, poly (vapor barrier) is run underneath and sealed to the core using acoustic seal. That same poly is then taped to the Interra.
This creates a continuous connection from the wall system into the roof assembly—tying the air barrier together without interruption.
How is the roof or ceiling assembly insulated?
The assembly starts with 1.5 inches of Halo Interra, which provides both the initial insulation layer and the air barrier.
On top of that, R-90 cellulose is blown in.
The approach is similar to a standard install—but with significantly more insulation to meet performance targets.
Were there challenges related to roof geometry and maintaining airtightness?
The geometry on this build was intentionally kept simple.
The house is designed with four corners to reduce exterior surface area while maintaining interior volume. This minimizes opportunities for heat loss and simplifies airtight detailing.
By avoiding complex geometry, the team reduced the number of transitions and potential failure points.
Did you use any specialty tapes, membranes, or gaskets at roof-to-wall transitions?
Yes—this transition includes multiple layers of sealing.
A top plate sits directly on the ICF concrete core, rather than spanning the full wall width. It matches the thickness of the Halo Interra (1.5 inches).
Once the trusses were installed, Halo Interra was run along the underside of the trusses and extended down to the top plate—fitting into the cavity between the truss and ICF wall.
From there, the Interra is taped to the interior foam of the ICF block, creating an additional sealed layer.
Before installing the top plate, a bead of acoustic seal was applied, along with 16-inch vapor barrier poly. This poly runs beneath the top plate and extends into the interior, where it is also taped to the Halo Interra.
The result is two layers of sealing protection at the wall-to-ceiling transition.
Why It Matters
The roof is where performance can break down—or come together.
On this project, it works because:
- The air barrier connects cleanly from wall to ceiling
- Insulation is layered and continuous
- Geometry reduces complexity
- Transitions are sealed with redundancy
Each detail supports the next.
Wrapping it Up
Airtightness isn’t one product.
It’s a system.
And when the roof ties back to the wall without gaps, breaks, or guesswork—you don’t just meet performance targets.
You build with confidence.
About the High-Performance Builder
Dennis Borren
Borren Builders | Central Alberta
Dennis specializes in high-performance ICF construction — building stronger, more energy-efficient homes and foundations across Central Alberta.
If you have questions about this article or are looking to collaborate, Dennis would be happy to engage with you:
Up Next in the Series
Read Part 4: Windows and Doors
This series documents one builder’s experience using our products on a specific project. Construction methods vary, and the details shown here should not be interpreted as a universal recommendation or endorsement.
