Submitted by Ken Roleke, NPI Franchise Owner, Tucson, Arizona
Before World War II, energy costs were low, and homes were usually built without insulation. Some houses were built without insulation as late as the early 1970s. As the fuel most commonly used for home heating went from wood to coal to oil and natural gas, it changed from locally sourced to an internationally traded commodity. Prices spiked with the OPEC oil embargo in 1973, leading to increased awareness and energy conservation.
There are U.S. Department of Energy codes and International Code Council codes that serve as guidelines, but energy codes are regulated at the state and local level. One exception is manufactured housing, which is subject to federal energy standards. The guidelines create climate zones, with higher R-value wall and attic insulation stipulated in the colder northern zones.
A home inspector inspecting an older house will check if, indeed, the house is insulated. The attics of most older houses have been insulated or had extra insulation added over time because the attics are usually accessible. Insulating the walls is more complicated and expensive. And, if there is no vapor barrier, moisture could get trapped in the wall cavities. It is easier to make sure there is a proper vapor barrier, insulating the exterior wall at the same time the exterior cladding is replaced, as opposed to blowing in insulation to stud cavities. An inspector will look for signs of moisture, mold, peeling paint and even rotting wood where the wall insulation retrofit was not done properly.
One insulation material seldom used now that an inspector may run across is vermiculite. Vermiculite mined before 1990 could contain asbestos and should not be disturbed. Sometimes foil was installed to reflect heat back into the house. Other older materials an inspector might see are slag wool, mineral wool, and even straw and old newspaper.
Today, a variety of insulation materials are used. Rigid insulation is made in a variety of sizes and materials and most often installed on the exterior wall side. There are SIPs, structural insulated panels, which are structural building panels made of boards with foam insulation sandwiched inside. There are spray foams that go in stud cavities, in the form of open-cell and closed-cell foams. There are ICF, insulated concrete forms, where rigid insulation serves as the stay-in-place forms for poured concrete walls. But those materials are more likely to be used in commercial, specialty and custom home construction, as they are more expensive than the two insulation materials that dominate house insulation.
Fiberglass is used in the form of plain batts and blankets, or faced with kraft paper or foil as a vapor barrier, and as loose fill. Cellulose is usually blown in as loose fill. Fiberglass has a higher R-value per inch than cellulose.
Home inspections are normally noninvasive, so an inspector will not always be able to identify the insulating material, although sometimes there will be an open wall cavity or hole that will allow him to do so. More often than not, there will be either visual or actual attic access, in which case the inspector will check the type of insulation used and check for proper installation. A common problem he will see is insulation missing or not evenly distributed. Using an infrared camera during the inspection can identify gaps and missing insulation that might not otherwise be detected in the walls and inaccessible areas of the attic.
With everything going on in the home-buying process, insulation is something the home buyer is probably not thinking about. A home inspector can determine whether a home is properly insulated, another facet of the home inspection that can save the home buyer from unexpected future expenses.
Tagged: attics, Energy Saving, home inspection, insulation, Ken Roleke