4.1003.1 Pitched/Vaulted/Cathedralized Ceilings—Loose Fill Over

Attic Ceilings
Desired Outcome: 
Reduce the rate of heat transfer through cathedral or vaulted ceiling Vaulted ceiling A condition where a non-horizontal ceiling has a different slope than the roof

Venting will be continuous, if applicable

Ensure capacity to increase R-value while not altering ventilation


Existence of rated insulation contact can lights, which allow for insulation encapsulation, will be verified

Non-insulation contact rated can lights will not be insulated

Prevent a fire hazard


When using cellulose, stabilized product is preferred when available

On roof pitches less than 6/12, loose fill cellulose can be used; on roof pitches greater than 6/12, install non-woven polypropylene netting (webbing) baffles of the same height as the insulation every 6' across slope to prevent the loose fill insulation from sliding downward, or  dense pack  cellulose above webbing stapled to the bottom (underside) of the rafters

Loose fill fiberglass will only be used on a slope less than or equal to a 6/12 pitch or the slope application approved by the manufacturer, whichever is less (dense packed fiberglass at slopes greater than 6/12 may be used)

Roof cavities will be insulated with loose fill according to manufacturer specifications without gaps, voids, compressions, misalignments, or wind intrusions

Insulation will be installed to prescribed R-value 

Ensure appropriate material and application

Insulate to prescribed R-value

Occupant education

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