Residential Maintenance Guide
Attic Maintenance
Insulation
With the exception of newer housing, almost every home can benefit from
improving the insulation. Saving money on fuel costs is perhaps the best
motivation for upgrading. There are usually some areas of the home where
it makes financial sense to upgrade. In some older homes, certain types
of upgrades do not make economical sense, such as insulating solid masonry
exterior walls. Be sure to weigh the cost savings vs. the cost of improvement.
The thermal resistance of insulation is measured in R-values. The higher
the number, the greater the resistance to heat transfer. Different types
of insulation have different R-values per inch of thickness. The same
type of insulation can have a different R-value depending on its form.
For example, fiberglass has a higher R-value in batt form than it does
in a loose form.
Types of Insulation
Fiberglass: Probably the most common insulation used, this material
is made from threads of glass glued together with phenolic resins. It
is available in batt form, loose form, and rigid board. It is resistant
to moisture, mildew, fungus, and vermin. Fiberglass can cause irritation
to eyes, skin and the respiratory system. R-Value is 2.9- 4.2 per inch.
Cellulose Fiber: The low cost of this material makes it a very
popular choice. Cellulose is made from shredded paper treated with chemicals
to make it resistant to fire, moisture, and vermin. This gray material
is typically blown into the attic. R-Value is 3.4-3.6 per inch.
Mineral Wool: Mineral wool (or rock wool) is very similar to
fiberglass in that it has good resistance to fire and rot. This type of
insulation is made from mineral waste products. It is available in loose
or batt form. R-Value is 3.0 to 3.2 per inch.
UFFI: Urea-formaldehyde foam insulation was banned in the United
States by the Consumer Product Safety Commission (CPSC) in 1982. Although
the ban was overturned by a federal court, few homes have installed the
product since 1982. New installations of UFFI is not advised due to potential
health problems, but homes that are already insulated with UFFI should
no longer have formaldehyde levels that present a significant health risk.
The color and texture of UFFI varies but it can be distinguished from
other foams by its frail, crumbly structure and powdery residue. Positive
identification can only be made by laboratory testing.
Insulation Maintenance
Over the years there have been many types of material used for insulating.
The above mentioned are the most common materials found during a home
inspection.
- Look for signs of water staining on the underside of the roof boards.
Indications of high humidity are rotting, mildew and fungus.
- Gable and roof vents should be checked for obstructions such as bird
nests.
- Check for evidence of pests (squirrels, raccoons, etc.)
- Be especially careful when walking around the attic - Don’t
fall through!
Ventilation
Having proper ventilation in your attic will help prevent damage to the
structure, increase the life expectancy of the roofing, reduce energy
use, and improve the living conditions below the attic.
The two main reasons for attic ventilation are heat and humidity. In
the summer the temperature in a poorly ventilated attic can reach 150
degrees! Excessive heat cannot only damage roofing materials, but it can
make the living area under the attic uncomfortable and difficult to cool.
Humidity will naturally drift upward to the attic from several sources
including showers, clothes dryers, cooking, and even breathing. Excessive
humidity can cause damage to the roof structure, insulation, and even
interior surfaces.
The requirements for proper ventilation will vary depending on which
part of the country you live in. The minimum recommendation is one square
foot of free vent area for each 150 square feet of attic floor (if there
is not a vapor barrier under the insulation). With a vapor barrier you
need half the amount. In older homes these requirements are usually not
met.
Good ventilation will usually be provided with the use of louver vents
in the gable ends of the home, ridge or box vents at the top of the roof,
and soffit venting under the eaves.
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