Home Construction Improvement

Installing Cellulose Spray-In-Place Wall Insulation

By Todd Fratzel on Energy Conservation, Insulation

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Today was another productive day for the crews building the Energy Star home that I’ve been writing about. Today a crew from Murphy’s Cell-Tech started installing the Nu-Wool spray-in-place cellulose insulation in the walls. Nu-Wool spray-in-place cellulose insulation is an amazing energy efficient insulation product. In addition to being such a great air barrier and insulation material cellulose is compromised of 100% recycled newspaper.

Nu-Wool cellulose insulation is spray applied into the wall cavities as a wet mixture. The mixture contains enough water to help thoroughly hold the material together when it’s sprayed in place. The contractors use a large box truck to transport the cellulose material. The truck also contains a large blower system used to spray the cellulose into the home. The blower system mixes together the cellulose in water and then shoots it through a long plastic pipe where the installer shoots it into the wall cavities.

As you can see in the photos (sorry for the poor quality images, as you can imagine there is so much dust and debris that it’s nearly impossible to take a photo) one of the contractors walks around shooting the cellulose into the wall cavity. The man is making sure he “over fills” the voids to be sure we have a full 5-1/2 inches of insulation depth. Another man follows him around vacuuming up the excess cellulose in recycling it back into the mix being sprayed.

In the next step one of the guys uses a rotating “sander” to “shave” off the excess cellulose leaving a smooth surface with exactly 5-1/2 inches of cellulose. If you ask me this is certainly a very “dirty” job best left to the professionals. Just like in the first step another man will follow behind this process to vacuum up the excess material so it can be recycled.

Finally you end up with a wall cavity filled with dense packed cellulose insulation. This method of insulation is far superior to traditional fiberglass insulation for many reasons. However, the biggest reason is the ability to block air flow. In addition to that every little crevice is filled with insulation including small holes in the framing.

In addition to the spray-in-place cellulose wall insulation you can read more about blown-in cellulose attic insulation and keep an eye out for a future post about properly air sealing the house.