Insulation Requirements
Reference: Table R402.1.2 of NC Energy Conservation Code. We are in Zone 3, the warmest part of NC.
Ceiling R-38 reqiured. R-30 could be used if the insulation could go all the way to the edge, but the sloped roof will not allow that (if there were a knee wall then R-30 could be used).
R402.2.3 "Soffit Baffle" indicates a baffle must be used to make sure air can come in via the soffit. The baffle may be any solid material.
Exterior Walls R-15. The table indicates one of two approaches can be used: at least R-15 in the wall or 13 in the wall and 2.5 via exterior sheathing. We choose the R-15 approach and will exceed it using R-19.
R402.2.14 "Framed cavity walls" requires that the insulation shall be enclosed on all sides with rigid material. E.g., put wall board on the walls!
R-19 floor value required. We will proably use R-19 unfaced inslation.
R402.2.8 Floors, Floor cavity insulation must be in permanent with the underside of the decking. Tension support wires must be spaced no more than 18" apart and within 6" of the insulation ends.
TBD - ask inspector if we can have an exception for the wire supports and use the R-15 + 1" styrofoam.
Crawl space wall: R-0. The table seems to imply that R-5 is needed. However, R402.2.11 Closed crawl space walls" indicates the walls only
need to be insulated if the above ceiling is not.
Table R402.2.11 "Wall Insulation allowances for termite treatment" indicates a gap of 3 to r inches must be left adjacent to the crawl space walls to allow for termite treatment.
R402.2.4 Access Hatches and Doors
Crawl space hatch and pull down stairs must have weather stripping and R-5 insulation.
We will have 1" styrofoam glued to bottom of crawl space hatch.
We will lay 2" thick styrofoam above the pull down stairs. If that does not pass inspection, we will do as instructed!
Continue at R402.4.1 Building termal envelope