4.1303.1 Insulation of Floor Cavity with Blown Material

Manufactured Housing Floor Cavity Insulation
Desired Outcome: 
Consistent thermal boundary Thermal boundary The separation between the interior and exterior environments of a building that slows heat flow between conditioned and unconditioned space that reduces heat flow

Insulation will be installed in accordance with recommended R-value and density

Insulate to prescribed R-value for the climate zone

Work assessment

Road and rodent barrier must be intact and free from holes and capable of supporting the insulation

Ensure bottom board is intact

Ensure insulation is supported

Protect cavity from infestation

Insulate floors

Each cavity will be insulated to specified R-value and density

The number of bags installed will be confirmed and will match the number required on the coverage chart

Eliminate voids and settling


Flame spread index of selected materials will not exceed 25 with an accompanying smoke-developed index not to exceed 450 when tested in accordance with ASTM ASTM ASTM International, www.astm.org E84 or UL UL Underwriters Laboratories 723

Flame spread index of foam insulation will not exceed 75 and a smoke- developed index of no more than 450 when tested in the maximum thickness intended for use in accordance with ASTM ASTM ASTM International, www.astm.org E84 or UL UL Underwriters Laboratories 723

Foam insulation will be separated from the interior of the building by an approved thermal barrier at a minimum of 1/2" gypsum or a material that is tested in accordance with the acceptance criteria of both the Temperature Transmission Fire Test and the Integrity Fire Test of NFPA NFPA National Fire Protection Association, www.nfpa.org 275

Selected material will be of minimal water absorbency

Selected material will be noncorrosive

Ensure durability

Prevent moisture damage

Fire safety will be maintained

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