Accessible Attic - Batt Insulation Over Existing Insulation

Detail ID 4.0103.3
Topic
Attics
Subtopic
Attic Floors - Unconditioned Attics
Desired Outcome

Continuous, contiguous, safe, and compliant thermal barrier installation

SF Single Family Site-Built Housing
MH Manufactured Housing
MF Multifamily Housing

Specifications

  • SF
  • MF
Specification Objective

Verify that installation area is free of:

active water leaks, fuel leaks (i.e., gas, oil, propane), and pest intrusions

energized or undammed knob and tube wiring

uncovered electrical junctions

improperly terminated devices (ventilation fans, dryers, plumbing stacks, condensate lines, combustion appliance flues/chimneys, etc.)

unshielded high-temperature devices (non-IC rated recessed lights, chimneys, flues, vents, etc.) unless they are zero clearance devices

insulation escape openings

Verify that installation area:

is intact, able to support insulation weight, and air sealed

Ensure space can be safely insulated

  • SF
  • MF
Specification Objective

When vented eaves or soffits exist, mechanically fasten insulation baffles in every roof bay that extend above the final insulation level by at least 6"

Install a minimum of one insulation depth marker and one marker every additional 300 ft2 throughout installation area with measurement beginning at the air barrier

Install flags at all utility junctions that can be seen above the final level of the insulation

Protect insulation R-value, provide depth measurement, and locate junctions for future access

  • SF
  • MF
Specification Objective

Select only unfaced insulation batts for installation over existing batt insulation that have a flame spread and smoke development index of 25/450 or less when tested in accordance with ASTM E84 or UL 723

Prevent condensation in insulation layers and choose fire safe insulation

  • SF
  • MF
Specification Objective

Install batt insulation to prescribed R-value in full contact with the existing insulation batts without gaps, voids, compressions, or misalignments

If the top of the existing insulation is below the top of the framing, install new batts parallel with framing members

If the top of the existing insulation is above the top of the framing, install new batts perpendicular to framing members

Uniform insulation depth in continuous contact with existing insulation without voids

  • SF
  • MF
Specification Objective

Post a dated receipt signed by the installer that minimally includes: Installed insulation type, coverage area, installed thickness, and installed R-value

Comply with 16 CFR 460.17 and document contract compliance