Four major types of loose-fill cellulose products have been developed under a variety of brand names. These are generally characterized as dry cellulose, spray applied cellulose, stabilized cellulose, and low dust cellulose. These insulation types are used in different parts of a building and for different reasons.
Dry cellulose (loose fill)
Dry cellulose is used in retrofitting old homes by blowing the cellulose into holes drilled into the tops of the walls. It can also be blown into a new wall construction by using temporary retainers or netting that is clamped in place then removed once the cellulose has reached the appropriate density. This form of application does settle as much as 20% but the stated R-value of the cellulose is accurate after settling occurs. In addition, a dense-pack option can be used to reduce settling and further minimize air gaps. Dense-pack places pressure on the cavity and should be done by an experienced installer.
Loose fill in walls is an antiquated technique of using cellulose in wall cavities. The home performance industry and its accrediting bodies support the dense-pack standard of insulating wall cavities, which does not settle. This method stops the stack effect and convective loops in wall cavities.
Spray-applied cellulose (wet-spray cellulose)
Spray-applied cellulose is used for applying cellulose to new wall construction. The differences are the addition of water to the cellulose while spraying as well as adding some kind of moisture retardant such as chlorine to prevent mold cultures. In some cases the insulation might also mix in a very small percentage of adhesive or activate a dry adhesive present in the cellulose. Wet-spray allows application without the need for a temporary retainer. In addition, wet-spray allows for an even better seal of the insulated cavity against air infiltration and eliminates settling problems. Wet-spray installation requires that the wall be allowed to dry for a minimum of 24 hours (or until maximum of 25% moisture is reached) before being covered.
Stabilized cellulose is used most often in attic/roof insulation. It is applied with a very small amount of water to activate an adhesive of some kind. This reduces settling and decreases the amount of cellulose needed. This can prove advantageous at reducing the overall weight of the product on the ceiling drywall helping prevent possible sag. This application is ideal for sloped roofs and has been approved for 5:12 (41.66%) slopes.
The last major type of cellulose insulation on the market is low-dust variety. Nuisance levels of dust are created during application of most types of dry insulation causing the need for simple dust masks to be worn during installation
Fiber glass insulation is one of the most prevalent forms of insulation used today. It offers many advantages and serves to control temperature in homes, as it helps to prevent air exchange between the inside and outside of homes. Fiber glass insulation also serves to control sound and helps homeowners to save money by lowering energy costs.
Glass wool is a thermal insulation that consists of intertwined and flexible glass fibers, which causes it to “package" air, resulting in a low density that can be varied through compression and binder content. It can be a loose fill material, blown into attics, or, together with an active binder sprayed on the underside of structures, sheets and panels that can be used to insulate flat surfaces such as cavity wall insulation, ceiling tiles, curtain walls as well as ducting. It is also used to insulate piping and for soundproofing.
Fiberglass batts and blankets
Batts are precut, whereas blankets are available in continuous rolls. Compressing the material reduces its effectiveness. Cutting it to accommodate electrical boxes and other obstructions allows air a free path to cross through the wall cavity. One can install batts in two layers across an unfinished attic floor, perpendicular to each other, for increased effectiveness at preventing heat bridging. Blankets can cover joists and studs as well as the space between them. Batts can be challenging and unpleasant to hang under floors between joists; straps, or staple cloth or wire mesh across joists, can hold it up.
Gaps between batts (bypasses) can become sites of air infiltration or condensation (both of which reduce the effectiveness of the insulation) and requires strict attention during the installation. By the same token careful weatherizationand installation of vapor barriers is required to ensure that the batts perform optimally. Air infiltration can be also reduced by adding a layer of cellulose loose-fill on top of the material.
Blown In Fiberglass Insulation
Loose-fill fiberglass insulation utilizes a professional blowing machine for installation in open spaces to fill hard-to-reach areas like corners, edges and around framing. As a premium alternative to cellulose, it does not settle or decay, and can effectively provide insulation for the life of the home. It can provide R-values from R-11 to R-60.