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Attic Access Insulation Requirements

Jim Melesky, ESS Energy Products, has spoken at several PENNBOC training events on this subject.  Most recently, at Region 5, there were a series of questions that Jim promised to research.  He has provided the results of his research to all PENNBOC members.

In this order you will encounter these resources:

  • Discussion paper - a compilation and explanation of code provisions related to attic access insulation
  • Response to participant questions - the code provisions regarding potential exceptions to non-rigid, non-compressible access insulation are explored and found not to be valid.
  • Compliance Checklist



Review of 2009 IECC, IRC & PA Alt. Energy Code

for Attic Accesses

Why is it important and what is compliant?


In discussions with a number of code officials and contractors, confusion exists as to what the precise minimum requirements are for attic accesses. This confusion stems from prescriptive vs. mandatory requirements in the 2009 IECC, the scope and meaning of a 2009 IECC REScheck Compliance Certificate and the definition of terms that impact the type of insulation that can be used.  This document is the product of input from code officials and other experts to produce a straight forward compilation of the code requirements.


Summary of the Code

Whether using the 2009 IECC with or without the 2009 version of REScheck, 2009 IRC or 2009 PA Alternative Residential Energy Provisions, the following minimum requirements apply for any attic access from a conditioned to an unconditioned space:


1.     Insulation R-Value (Choose one)

  • REScheck Compliance Certificate
  • R-Value Equivalent to the rest of the attic
  • R-20 for PA Alt.

2.     Type of Insulation

  • For the IECC or IRC, access must prevent damaging or compressing insulation ( i.e., no exposed  Batt insulation, but this does not exclude the use of loose fill or batt in a measure that prevents compression of the insulation)
  • For PA-Alt, it must be rigid foam (i.e. no batt or loose fill insulation can be used)

3.     Protective Barrier around the opening

  • Wood
  • Equivalent (i.e., Plywood , rigid foamboard-no batt insulation or cardboard)

4.     Durable Air Seal

  • Continuous air sealing measure (i.e., no gaps)
  • Air sealing material must have tolerance to attic temperatures

5.     Size and Location

  • Opening 22x30 inches or greater
  • 30 inches of unobstructed clearance
  • Located in hallway or other readily accessible area



There are a number of factors that led up to the adoption of the new code requirements for attic accesses.  First, it is known that more energy is lost through the attic than any other area of a home.  The use of the thermal camera, blower door device and computer modeling revealed the large amounts of conductive and convective heat transfer that occur through attic accesses in both hot and cold weather. 

UA calculations were first used in weatherization for calculating the insulating value of an area with uneven levels of insulation.  This calculation proved that an attic access without insulation will significantly reduce the insulating value of the total attic. Further, since the attic access cover will be moved to enter and exit the attic, it is important that the insulation used is durable and not subject to being compressed or otherwise compromised. 

Loose fill insulation has increasingly been used instead of batt insulation.  This insulation can readily fall into the living space when entering and exiting the attic thereby creating a need for a blocking device to keep loose fill insulation in the attic and maintain a consistent insulating value in the area around the attic access.

Blower Door tests reveal that more air leakage and the accompanying convective heat transfer occurred through the attic than originally suspected by many.  With the tightening of the thermal envelope everywhere else in the structure, any remaining opening such as the attic access will be a source of increased air leakage.  Air leakage through the attic access in the otherwise tightened thermal envelope contributes to or causes other significant problems in the structure such as rainy attics, mold and ice damming. 


The Code

The standards for attic hatches and doors address each of the above items.  The new standards exist primarily in two separate and distinct sections of each code.  For the 2009 IECC, sections, 402.2.3 and 402.4.1 present the specific new requirements.  For the PA Alternative Energy Code and IRC, the same wording exists in sections PA 302.3 and PA 304.1 as well as N1102.2.3 and N1102.4.1 respectively.  The 2009 IRC contains additional pertinent requirements in sectionsE3501.1, R201, R807.1 and M1305.1.3.

Section R807.1 requires a minimum rough framed opening for the attic access to be not less than 22 x 30 inches with minimum unobstructed headroom of 30 inches above the ceiling framing members.  For wall openings, a minimum size rough framed opening is not less than 22 wide and 30 inches high.  Finally, the attic access must be located in a hallway or other readily accessible location.

Section M1305.1.3 of the IRC requires attic access openings to be large enough to allow removal of the largest appliance.

Sections 402.4.1 of the IECC, N1102.4.1 of the IRC and 304.1 of the PA Alt. have a new requirement for attic access openings to be durably air sealed.  Since this is a mandatory requirement in the IECC, it cannot be addressed by a simulated performance alternative.  It is noteworthy that the requirements for air sealing are now the same for site built doors, windows, openings between window and door assemblies and their respective jambs and framing, and skylights as they are for attic accesses.

Section 402.2.3 has the following new prescriptive requirements:

  1. Insulation R-Value equivalent to the rest of the attic
  2. Wood or Equivalent protective baffle when loose fill insulation is installed
  3. Access to equipment that prevents damaging or compressing the insulation
  4. Weather stripping

Sections201.3 of the IRC and R202 and E3501.1 define equipment as all piping, ducts, vents, control devices, and other components of systems other than appliances that are permanently installed and integrated to provide control of environmental conditions for buildings.  Equipment also includes material, fittings, devices, luminaires, apparatus, machinery and the like used in part of, or in connection with, an electrical installation.

For the PA Alt, it states that the scope and definitions used in the IRC apply.  Therefore, the above definition for equipment applies to the PA Alt.

Section 401.2 allows for prescriptive requirements of various sections and specifically Section 402.2.3 to be met by section 405, Simulated Performance Alternative.  This includes the use of approved compliance software tools such as the 2009 REScheck software. 

The 2009 IRC in section N1102.2.3 contains the same requirements as those listed in 402.2.3 in the IECC.  However, the IRC does not have prescriptive and mandatory distinctions.  PA 302.3 requires a minimum of R-20 of rigid foam.  PA 302.2 also requires a wood or equivalent baffle or retainer when loose fill insulation is installed.

REScheck-What it addresses and what is not included

The REScheck program provides an alternative measure for the insulating R-Value requirement of the attic access.  This is accomplished with a UA calculation for the entire structure.  This calculation takes into account the fact that there are areas of a structure where it is not feasible to have levels of insulation that meet the required R-Value.  This alternative reduces the R-Value requirement for the attic access in most cases. 

REScheck is clear in the scope of what it addresses: “REScheck is appropriate for insulation and window trade-off calculations in residential detached one- and two-family buildings and multi-family buildings three stories or less in height above grade, such as apartments, condominiums, and townhouses. REScheck works by performing a simple U-factor x Area (UA) calculation for each building assembly to determine the overall UA of a building. The UA that would result from a building conforming to the code requirements is compared against the UA for your building. If the total heat loss (represented as a UA) through the envelope of your building does not exceed the total heat loss from the same building conforming to the code, the software generates a report that declares your building is compliant with the code.” Source:

If the REScheck program is used and the insulating values are met for the total structure including the attic access, then it produces a 2009 IECC Compliance Certificate despite the fact that the only information submitted on the REScheck checklist pertaining to the attic access is “Attic Access Hatch & Door insulation R-Value of the adjacent assembly”.  The explanation of the scope by REScheck as well as the REScheck checklist itself clearly states that the 2009 REScheck compliance certificate only covers the insulating value of the attic access.

REScheck does not have any entry for the requirements listed in 2-4 above for wood or equivalent protective baffle , access that prevents damaging or compressing the insulation and weather stripping.

The 2009 PA Alt specifically requires a minimum of R-20 rigid foam, a wood or equivalent protective barrier and a durable air seal /weather-stripping for any attic access.

The purpose of these other 2009 IECC requirements is clearly stated in the code.  For example, “a wood or equivalent baffle or retainer is required to be provided when loose insulation is installed” It goes on to clarify, “the purpose of which is to prevent the loose fill insulation from spilling into the living space when the attic access is opened, and, to provide a permanent means of maintaining the installed R-Value of the loose fill insulation.”  This is an important for the resident(s) in that insulating is prevented from entering the living space as well as a means to achieve and permanently maintain the proper insulating value in the attic.  Again, this requirement is not included in the REScheck check list.

The need for a measure that prevents compression is also straight forward -“Access shall be provided… that prevents damaging or compressing the insulation.”  The requirement is unequivocal that the insulation used on the attic hatch or door must prevent the damaging or compressing of the insulation.  Exposed batt insulation on the access hatch or door is readily subject to being compressed when accessing the attic. The requirement is that it must prevent such an occurrence not that if one is careful it may not compress the insulation.  Therefore, exposed or unprotected batt insulation is contrary to this requirement.  However, if batt or loose fill insulation is used in a measure and that measure is constructed so that it prevents compression of the batt and/or loose fill insulation, then it would be consistent with the code.

The PA Alt specifically calls for a minimum of R-20 rigid foam insulation, thereby prohibiting the use of batt insulation.

Based on the clarity of purpose from the explanation provided in the code, it is common sense that insulation must be used that prevents compression, a protective barrier and weather stripping are needed.   Nonetheless, a reading of just the authorized use of REScheck and the Prescriptive requirements that are in 402.2.3 may at first appear to be inconsistent.   Sections 101.4 and 303.2 provide clarity to resolve this potential conflict.  (Note that the same requirements exist in sections R102.1 and N1101.7 of the IRC and section PA 111 of the PA Alternative Energy Code respectively)

Section 101.4 titled Applicability states that, “Where, in any specific case, different sections of this code specify different materials, methods of construction or other requirements, the most restrictive shall govern.”  Following this guidance, having a protective barrier is more restrictive than no barrier and having insulation that is prevented from compression over the attic hatch or door to the attic is more restrictive than every type of insulation.  That logic is consistent with the common sense approach above.

Section 303.2 provides further clarity on both of these requirements as it states that, “All materials, systems and equipment shall be installed in accordance with the manufacturer’s installation instructions and the International Building Code.”  The manufacturers of batt insulation such as Owens Corning[i] indicate that “To get the marked R-Value, it is essential that this insulation be installed properly.”  “Insulation should not be compressed… as this results in a reduction of R-Value.”  Relying on the requirement to follow the manufacturer’s installation instructions, it is clear that the use of insulation that is prevented from compression is required and insulation that can be compressed cannot be used to insulate the attic access. 

Again referencing Owens Corning and its installation instructions for loose fill insulation, it states that, “Failure by the installer to provide… at least the minimum thickness will result in lower insulation R-Value.” [ii] Without a protective barrier around the attic access, the loose fill insulation will need to be tapered as it approaches the opening or the insulation will fall freely into the living space.  In either case, the loose fill insulation will not meet the thickness required for the stated R-Value.  Absent a viable protective barrier or the contractor entering an additional ceiling component, the R-Value stated on the REScheck checklist for the ceiling will be inaccurate, thereby producing an inaccurate and invalid compliance certificate and/or non-compliant for failure to comport with section 303.2. 


Common  Measures that are Non-compliant with REScheck

A structure with or without a 2009 IECC REScheck Compliance Certificate can often be non-compliant for:

  1. Bare Batt insulation on the hatch and door covers
  2. Inaccurate R-Value entries in REScheck (Continuous vs. Cavity, incorrect Ceiling Components or use of “Effective R-value” rating on insulation)
  3. No air sealing measure or Gaps in the air sealing measure
  4. Air sealing measures that are not durable
  5. No Protective Barrier with loose fill insulation
  6. A Protective Barrier made of batt insulation or cardboard

This does not preclude the use of batt or loose fill insulation in the rest of the attic.



Consistent enforcement of the code is essential.  These requirements are intended to stop a very significant source of energy loss.  Failure to comport with the requirements will not only cause energy loss, but can also contribute to or lead to other serious problems including condensation, mold and ice damming.


[i] Owens-Corning Website  ( EcoTouch R-21 High Density (for 2x6 Exterior Walls) Data Sheet.pdf)

[ii] Owens-Corning Website (



Compliance Checklist


By Admin
Mon, 27 Jan 2014 14:47:15

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