4.1003.9 Installing Fiberglass Blown Insulation for Flat, Bowed, or Vaulted Ceilings (via Exterior Access from Top of Roof)

Topic: 
Attics
Subtopic: 
Attic Ceilings
For supporting material, see Building America Solution Center.
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)
4.1003.9a
Attic, ceiling, and roof verification

All combustion appliance flues will be terminated to the outdoors and terminations will maintain proper clearance above snow loads

A distance no less than 2" will be maintained between any combustion appliance flue and combustible materials, unless zero clearance flue is in place

All ventilation systems will maintain a continuous connection and terminate to the outdoors

All broken mushroom vents will be replaced or removed and sealed

All plumbing stacks will be terminated to the outdoors

Non- IC IC Insulation contact rated light fixtures will be replaced with airtight IC IC Insulation contact -rated fixtures

All recessed lights will be labeled as having an air leakage rate not more than 2.0 CFM CFM Cubic feet per minute when tested in accordance with ASTM ASTM ASTM International, www.astm.org E 283 at a 75 pascals pressure differential

All obvious ceiling penetrations will be sealed

The space between combustion appliance flues and the ceiling will be sealed with fire-rated materials

All roof, attic, and ceiling assemblies will be structurally sound:

  • Loose ceiling panels will be secured
  • Temporary ceiling bracing will be recommended during the insulation installation process

Dishing and pooling issues that allow standing water will be addressed

All known roof water leaks will be repaired before installing installation

Ensure occupant and worker safety

Verify attic space is ready to insulate

Ensure structural integrity of the roof and ceiling assembly

Prevent intrusion of bulk moisture

Prevent damage while installing insulation

4.1003.9b
Attic access

Access to the attic cavity will be created through the gable vents.

Attic will be visually inspected for the location of existing insulation, wiring, flues, obstructions, hazards, and construction type

Create access to the full attic cavity

Maintain the integrity of the roof truss

Determine technique for installing insulation

4.1003.9c
Blowing machine set up

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

Hose outlet pressure will be set in accordance with manufacturer specifications

Ensure machine is capable of delivering uniform insulation density and coverage

4.1003.9d
Fiberglass blown insulation installation

Insulation will be installed to a density of 1.5 to 1.6 pounds per cubic foot

Using fill tube, 100% of each cavity will be filled to a consistent density

Fill tube will be inserted within 6" of the end of each attic cavity

Insulation will be installed into the void of the attic cavity:

  • If existing insulation is roof-mounted, insulation will be blown below
  • If existing insulation is ceiling-mounted, insulation will be blown above
  • If existing insulation is mounted at both locations, insulation will be blown in between

Insulation will be filled no higher than the top of the truss

Flame spread and smoke-developed index for insulation will be a flame spread rating of 25 or less and a smoke development rating of 450 or less when tested in accordance with ASTM ASTM ASTM International, www.astm.org E84

Fill entire attic cavity to the prescribed R-value to reduce air infiltration Infiltration The uncontrolled passage of outside air into a building through unintended leaks in the building envelope

Avoid clogging of the cavity and the fill tube

Prevent damage to the ceiling

Allow roof to be returned to original position

Fire safety will be maintained

4.1003.9e
Patching and sealing openings

If the roof is sliced:

  • A solid metal ridge cap will be centered over the slice
  • A flexible and durable sealant will be sandwiched between the roof and the ridge cap
  • Screws will be installed to prevent wrinkles and create a permanent seal
  • Screws will not go into any wood framing
  • A durable and flexible final coating will be applied over the screws and edge of the ridge cap to create a continuous seal between the roof and the perimeter of the ridge cap

For holes that are drilled or cut, the initial patch will be applied using the following procedure:

  • At least 6" of surface surrounding the opening will be cleaned before patch is installed
  • Sealant will be continuous and applied in between the patch and the roof
  • Sealant will be an all-weather adhesive that is flexible and durable

If a metal patch is used:

  • Patch will overlap the opening by 2" on all sides
  • Gauge will be equal to or greater than the roof material
  • Fasteners will be installed to prevent wrinkles and create a permanent seal
  • If a plug is used, it will be flanged and have a tight fit
  • Screws will not go into any wood framing

A durable and flexible 45 mil adhesive patch will be applied in accordance to manufacturer specifications over the initial patch and will have at a minimum:

  • Tear strength of 640g
  • Elongation of 380%
  • Application temperature no lower than 55°F and no greater than 110°F
  • Services temperature no less than -25°F and no greater than 150°F
  • Adhesive patch will overlap the initial patch by 2" on all sides
  • A durable and flexible final coating will be applied over the adhesive patch to create a continuous seal between the roof and the perimeter of the patch
  • All remaining seams, edges, and penetrations will be sealed as necessary

Effectively patch and seal all openings

Create a durable patch that will prevent roof leaks

4.1003.9f
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

4.1003.9g
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 complete

Comply with 16 CFR 460.17