Disadvantages • lower R-value per inch than most other insulation products in use today
• losses it R-value when wet and does not recover well if saturated wet
• tends to settle in attics and when blown into walls without binders (glue), losing R-value
• does not provide an integral vapor barrier
According to the University of Massachusetts Building and Construction Technology department, wet cellulose takes a long time to dry. While fiberglass may be faced with drywall as soon as the insulation is installed, wet cellulose must lose at least 75 percent of the water in it before installing drywall. Depending upon humidity, spray cellulose insulation may take weeks to dry, and professional sprayers will use space heaters to speed up the drying. From what I have seen in Thomasville, Georgia the day after insulation is applied the drywall goes up.
We spray Icynene and occasionally lose jobs to wet spray cellulose. I've used an infrared camera to look at walls of two existing homes that had wet spray cellulose applied. There were many cold spots, some apparent voids, and some settling. We have "dumped" a stud cavity of freshly applied wet spray cellulose onto poly, weighed the material, and dried it. There was approximately 0.9 gallon (ca. 7 pounds) of water in the cavity. We have been on a job site the day after the application of wet spray cellulose and have seen the sagging, settling, and falling out of the cavity. Sheet rock is typically applied within a day of application of the wet spray cellulose. I cannot comprehend the use of a wet product in a wall (wet things tend to shrink, settle, and sag) and then covering it up immediately (probably good practice from the perspective of the wet spray cellulose applicator). I would like your perspective/experience with wet spray cellulose and would like to find some "science based" studies on wet spray cellulose and other insulation products.
Concerns that have been raised about wet-spray cellulose Insulation and its effectiveness.
