August 20, 2014

Cellulose

Dense Pack Insulating
We use the term “dense pack” when we are referring to cellulose installed at densities of 4.0 lbs/cuft.  The settling and moisture problems of the past have been largely overcome with the advent of the dense pack cellulose installation technique. This technique involves drilling a single hole into each stud cavity, then feeding a flexible rubber hose into this cavity until it reaches the opposite end. The hose is then pulled back approximately one foot before the insulation blower is started. As the insulation fills up the cavity, it creates a back pressure in the hose reducing the flow of the insulation. When this occurs, the hose is withdrawn several inches, and this process is repeated until the cavity is completely filled.

Advantages of Dense Packing
By targeting our dense packing measures effectively, we can reduce the conductive, convective and air filtration heat losses from a building. The conductive heat losses are reduced by the additional R-value provided by the cellulose. Dense packed cellulose has an approximate R-value of 3.5 per inch. Heat loss attributed to convection currents within bypasses is reduced by effectively stopping air movement within the cavity once a dense pack is achieved. Air infiltration is reduced as the dense pack provides an effective air barrier, slowing down, and in some cases stopping, the overall movement of air through the building’s envelope. Studies have shown that up to 33% of the building’s air leakage, as measured with the blower door, can be eliminated using dense pack cellulose.