3123 -- A Study of the Filling of Wall Cavities with Retrofit Wall Insulation PDF

The Pacific Northwest Power Marketing Agency, the Bonneville Power Administration (BPA), conducted a retrofit wall insulation study to determine (I) the effects of various obstructions within a wall cavity, (2) where voids are likely to occur, and (3) preferred filling methods and material types. The insulation test structure was composed of four 8-foot x 12-foot walls, and was built using standard construction practices. The inside walls were clear plastic glazing, instead of gypsum board, to enable viewing of the filling process. A total of eight tests were performed: four cellulose, two rockwool, and two fiberglass. One- and two-hole filling methods were observed. All insulations were found to perform in the same basic manner with all experiencing the same problem areas. Common installer problems were empty spaces at the tops of cavities and missed cavities, especially above headers. Wiring and lath and plaster consistently caused reduced insulation densities in cavities. The problems with wiring, lath and plaster, and other features in the wall cavities were avoided with the use of a filler tube. The filler tube also provided a more consistent fill along the length of the entire cavity.

Units: I-P