Charlie Huntington of I&S Insulation (for Itchy and Scratchy) of Newcastle was the first speaker, presenting options, not only for new construction, but also for retrofitting older homes.  About thirty people were in attendance.

The first issue he tackled was the resistance factor.

Resistance, or R-value, is a number that relates to the amount of thermal resistance - heat that cannot escape a building due to insulation.  When there is no insulation, the R factor is one, and as insulation is added, the factor goes up.  A house that has an R-30 value has thirty times the thermal resistance that a home that has an R-1 value has.

Huntington, however, suggested that R-value is not the most important thing to consider.  The type of insulation used seals the building, and some materials seal it better than others.  Since the envelope needs to be sealed, even more than it needs extreme R-values, it is important for the homeowner to look at how the material seals the building.  Fiberglass, according to Huntington, doesn’t seal very well at all.  He set up two pieces of wall with several types of insulation, and showed how dense pack cellulose and isocyanate foam work better than either roll-in fiberglass or blown-in fiberglass, without adding unnecessary volume.

The fiberglass, in a standard six-inch wall has an R-value of 19, whether it is rolled or blown in.  Isocyanate foam, however, can do the same job in only three inches.

At some point, there is a diminishing return for adding R-value, but as fuel prices soar, that return is increasing all the time. 
In new construction, Huntington recommends a few inches of foam to seal the building, then add fiberglass on top to add R-value.  For older construction, he prefers to blow in cellulose.  “It’s absolutely the best bang for the buck,” he said.

Huntington also dispelled some myths.  New foam does not contain formaldahyde, but contains polyurethane instead, making it much safer for installers and homeowners.  Despite what some believe, dense-pack cellulose does not settle and leave air gaps at the top. 

Many people are concerned about insulation fires, especially with dense pack cellulose.  All insulation will burn, but dense-pack cellulose is extremely fire resistant, because it contains some sort of fire inhibitor.

For those concerned about the fire issue in spray-in foam on cellar walls, it is possible to paint the insulation using intumescent paint, which is fire-retardant.  By spraying the paint on about 1/4 inch thick, the paint protects the insulation from incidental fire pretty well.

For insulation of basement ceilings, it is important to remember the rule about where the vapor barrier goes.  Vapor barriers must be installed on the warm side of the insulation, which is generally closest to the ceiling in an unheated basement.  This is because condensation as water vapor moves from the warm side of the wall to the cold side.  If you install it on the wrong side, it traps moisture in the envelope, making moisture problems worse, and possibly causing mold damage to your floors and ceiling.