Home Inspection Services

Gaps or voids in any insulation material, account for significantly poorer thermal performance, so proper installation is important.

Wall insulation is more complicated to install than attic or underfloor insulation. It's best to contact a professional insulation contractor. A professional has the experience to work efficiently, effectively, and recognize unexpected problems.

An experienced crew with good equipment can insulate the walls of an average house from start to finish in less than one day. One crew member drills the wall cavities and probes for blocking. Another follows with the nozzle and hose from the blowing machine and fills the cavity with insulation. An ordinary wall section that is 8 feet in height requires two holes, one about 12 inches below the drop of the wall and the other one up about 36 inches from the bottom of the wall. A wall 10 feet in height may need three holes to achieve adequate compaction of the insulation throughout the cavity (depending on the equipment).

After the installation, the holes are plugged with a wood or plastic plug. The plug is painted if the homeowner supplies the paint. Another option includes a plug with spackle over it. Most insulation contractors stress this is not a finished job and matching colors and textures is not their specialty. Plugs installed without adhesive may work their way out over time because of changing moisture content and temperature. Patching compounds can be textured to blend with existing surfaces.

After the work is completed, a professional installer is required by law to leave a certificate that specifies how much material was installed, how many square feet it covered, type of material used, date of installation, and the installer's name. To prevent settling of material (that could result in voids or gaps), contractors install more insulation in each cavity than will it holds at settled density. For example, cellulose will settle to a density of 2.3 pounds per cubic foot, but your contractor should press more than 3.0 pounds into every cubic foot. The possibility of settling is then greatly reduced.

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