4.1003.11 Installing Fiberglass Blown Insulation in Roof-Over Constructions

Topic: 
Attics
Subtopic: 
Attic Ceilings
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
TitleSpecification(s)Objective(s)
4.1003.11a
Roof-over overview

If occupant will allow access from interior, installation through the ceiling is preferred

Attic space created by the roof-over will be accessed in accordance with the Single-Family Attic Access SWS

If the roof-over does not allow physical access to the roof-over attic, access to the original attic will be gained through roof venting

If existing insulation height in the attic is less than the height of the heel plate (original attic), access will be made through the original roof and the original attic cavities will be filled before blowing insulation over the original roof

At a minimum, the access holes to the original attic cavities will be sealed to prevent air leakage

If existing insulation height is equal to or greater than the height of the heel plate (original attic), the insulation will be installed in the end cavities before blowing on top of the original roof

Access to the end cavities will be gained and insulation will be installed

At a minimum, the access holes to the original attic cavities will be sealed to prevent air leakage

Insulation will not be installed on top of the original roof until the end cavities are insulated and air sealed in original attic

If insulation is installed on top of the original roof, it will be installed in accordance with the Single-Family SWS Loose Fill Blown Fiberglass Insulation Installation

Gain access to the combined attic spaces

Address thermal bridging

Correctly insulate the combined attic spaces

4.1003.11b
Onsite documentation

A dated receipt signed by the installer will be provided that includes:

  • Insulation type
  • Coverage area
  • R-value
  • Installed thickness and minimum settled thickness
  • Number of bags installed in accordance with manufacturer specifications

Document job completion to contract specifications

Confirm amount of insulation installed

Ensure ability to match bags required for total area completed

Comply with 16 CFR 460.17