4.1088.6 Installing Insulation at Flat and Cathedral Ceiling Transition Wall

Special Considerations
Desired Outcome: 
Consistent, uniform thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow and air barrier Air barrier The separation between the interior and exterior environments of a building that slows air flow to the point that no smoke movement is visible at 50 pascals of pressure difference across the boundary between the conditioned space and unconditioned space
Insulation installation verification

A visual inspection of the highest point of the transition wall will be completed

Access points will be determined from the gable end, roof, ceiling, or interior paneling

Verify the height and the accessibility of the attic

Access attic

Attic will be accessed through the location that allows the most efficient and effective insulation coverage

Gain access to the flat and cathedral ceiling Cathedral ceiling A condition in which the ceiling has the same slope as the roof transition wall


Blowing machine pressure test will be performed with air on full, feed off, and gate closed

Insulation will be blown against the transition wall until the wall is covered

Ensure machine is capable of delivering uniform insulation density and coverage to meet manufacturer specifications for loose blown insulation

Create a thermal barrier at the transition wall

Spray two-part foam

Insulation will be installed to prescribed R-value in accordance with manufacturer specifications

Spray polyurethane foam ( SPF SPF Spray polyurethane foam ) will be applied to desired thickness, using pass thickness maximum as indicated by manufacturer

Insulate and seal transition wall


Batt insulation will be installed in accordance with manufacturer specifications without gaps, voids, compressions, misalignments, or wind intrusions

Insulation will be installed to the prescribed R-value

Vapor barrier Vapor barrier A material that retards the passage of water vapor and contains a perm rating of less than 1 will be installed based on regional considerations

Insulate to prescribed R-value

Patching and sealing access points

Created access points will be covered and sealed in an aesthetically pleasing manner

Existing access points (e.g., gable vent) will be returned to the original condition

If existing trim was removed, it will be reinstalled

Create an airtight seal

Create an aesthetically pleasing finish

Verification of details

Installation process will be considered complete when installer has verified that damage has not occurred to the roof or ceiling assemblies during the installation process

Verify the integrity of the house has been maintained

Onsite Documentation
A dated receipt signed by the installer will be provided that includes:
  • Insulation type
  • Coverage area
  • R-value
  • • Installed thickness and settled thickness (settled thickness required for loose-fill only) • Number of bags installed in accordance with manufacturer specifications (for loose-fill only)
Document job completion to contract specifications Confirm amount of insulation installed Comply with 16 CFR 460.17