UNDERSTANDING R-VALUE
R-Value is used to measure or rate an insulating material’s resistance to heat flow. Simply put, the higher the R-Value, the better the insulating material. There are a few factors that determine the insulation’s R-Value, including the type of material, the density of the material, and the thickness of the material. In order to maximize a materials full R-Value it is very important to correctly install it.
WHERE TO INSULATE – THE ‘ABC’ RULE
During an energy assessment we determine what areas of the home need to be addressed. We prioritize the areas of your home by using the ABC Rule. In order of importance, we assess (A) The Attic, (B) The Basement, and (C) The Conditioned Space. We prioritize them in this order because improvements made to the attic will have a greater impact on reducing stack effect compared to the basement or conditioned space, etc. We know that each and every home is different so we take a customized approach to every home we visit.
TYPES OF INSULATION
We use a wide range of insulation materials such as cellulose, fiberglass batts, and rigid foam to properly insulate your home. In order to determine which insulation material to use, we first assess the area in need of insulation.
Cellulose insulation is made from recycled paper products and contains the mineral borate to deter insects and create fire resistance. In new or existing homes it is a very common to use blown in cellulose in the attic and then dense pack cellulose into exterior walls. Local building code will dictate the depth of cellulose needed to hit a certain R-Value in the attic. In new construction, netting can be stapled to the studs and then the cellulose can be blown in behind the netting. In existing homes, the exterior siding can be removed and holes can be drilled in the sheathing in order to blow cellulose into the wall cavity. We use a machine and hose to blow the material into the wall cavity to a certain pressure. Once the wall cavity reaches a certain pressure the machine will turn off and we will move to the next cavity. We call this process dense packing.
Fiberglass is another common insulation material that consists of fine glass fibers. Fiberglass is used most commonly in the form of fiberglass batts. Fiberglass batts can be laid down in empty bays in between the ceiling joists in the attic. In new construction, fiberglass batts can be stapled into the exterior wall cavities in between the studs.
Polyisocyanurate or polyiso is a closed-cell, rigid board that consists of a foam center with two facers on each side of the board. Polyiso board is commonly used in basements to insulate and seal the rim joist as well as a crawlspace ceiling. Polyiso board is also quite frequently used in the knee wall area. Polyiso board has an extremely high R-Value of about 6.5 per inch. Compared to other insulating materials, polyiso board has superior resistance to moisture and vapor as well as fire. When installed properly, polyiso board will greatly reduce air infiltration.