65-407 C.M.R. ch. 400, § 5 - ACCEPTED PRACTICES

A. Frost Line

For determining compliance with this section of the Standards, the design frost line shall be those listed in Table 1 for each zone as found on the Zone Map.

Table 1 Design 1 frost line for conforming to the requirements of Maine's Energy Efficiency Building Performance Standards when installing insulation on foundations or slab-on-grade floors.
Zone	Design Frost Line in Feet Below Grade
1	4 feet
2	5 feet
3	6 feet

B. Ceiling Insulation

Ceiling insulation shall be installed in a manner which maintains the minimum depth of insulation needed to achieve the minimum specified R-value. The measurement shall be taken at the outside edge of the exterior wall framing.

C. Maintenance of R-value

The following measures shall be installed to maintain the integrity of the R-value of the installed insulation:

1. Wind Wash - A continuous air barrier must be provided at the following locations to mitigate wind wash:

a the exterior edge of ceiling insulation; and

b cantilevered floors and bay windows, including corners with adjoining vertical walls above and below.

2. Moisture and Vapor Control

a A continuous vapor retarder shall be installed on all walls and ceilings which face outdoors or unheated spaces. The retarder shall be installed at or near the warm (interior) side of the insulation, but in no case may be placed more than 1/3 of the R-value into the insulation.

b A vapor retarder or a capillary break shall be installed under all slabs. The retarder may be covered by a thin layer of sand to protect it from damage during the construction of the slab.

c A vapor retarder shall be installed on top of all dirt crawl space floors. All joints in the retarder shall be lapped and sealed. The edges of the retarder shall be wrapped up onto the foundation walls a minimum of 6 inches, then sealed and mechanically fastened to the foundation.

Notes

65-407 C.M.R. ch. 400, § 5