These requirements of Oregon's Energy Trust are not attainable without unjustified cost and inconvenience:
>R30 for a ceiling portal, >R15 for a wall portal, and >R10 for a drop-down ladder.
Further, they are not required by Oregon's implementation of the 2008 International Energy Conservation Code, IECC. The "real" rules say only that an outside door must be U less than 0.2, R5. The special case of an attic access is not addressed. Volunteering more-restrictive rules for a path under less thermal stress makes no sense.
There are precedents for the zeal, excused as diligence. The parent IECC seems to say:
- - - well, I can't even copy and paste. This is retyped from a read-onlysummary:
Requires attic access hatches and doors from conditioned space to unconditioned space to be weatherstripped and insulated to the level equivalent to the assembly where it is located.
How mean that one must pay ICC $34 to do more than glimpse a snippet of the rules they presume to impose on the public. I wonder if ICC will now sue me for posting the paraphrased summary words without copy protection. (I started to join ICC, to at last buy and read IECC codes, last December. That failed when I could not get the no-cost pdf download that should be freely available, along with the probably-slim print copy gratis with $100 membership.)
Energy Trust of Oregon has spared me some of the sting of the IECC zeal, but remains zealous compared to Oregon Department of Energy. Some inspectors holding IECC, and some state authorities impose the full R38 or R49 floor requirement, for an attic portal. Still, I see the rules including even R10 for an attic ladder not as diligence, or zeal, but as a heedless endorsement of tarps. In majority, the public does not go along. Tarp sales are slow. I will never touch one.