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Building Components ...


There is a lot for an inspector to see in an attic, provided that it is accessible and visible.  The underside of the roof and the roof support system are usually visible and can be inspected.  In addition, attic insulation, ductwork, and ventilation can often be seen as well.  However, flooring and insulation may obscure water pipes, electrical conduits, junction boxes, exhaust fans, and other components. 

Attic Insulation

Even in attics that have flooring, the attic insulation is usually visible.  In our area, we find many different types of attic insulation.  Here are some of the more common types we see: 

Batt or Blanket Insulation -

Blanket insulation, the most common and widely available type of insulation, comes in the form of batts or rolls.  It consists of flexible fibers, most commonly fiberglass although some can be made with mineral wool, plastic fibers, and natural fibers, such as cotton and sheep's wool.  It is a popular attic insulation because of its relatively low cost and ease of installation.  The U.S. Department of Energy publishes additional information in Batt and Blanket insulation and other attic insulation topics

Blown-in or Loose-fill Insulation -

Loose-fill insulation consists of small particles of fiber, foam, or other materials that are blown into place.  These small particles form an insulation material that can conform to any space without disturbing any structures or finishes.  The most common types of materials used for loose-fill insulation include cellulose, fiberglass, and mineral wool, and contains a varying amount of recycled materials.  The US Department of Energy publishes additional information on loose-fill insulation, as well as information on other types of insulation

Vermiculite Insulation -

Vermiculite is a mineral that expands at high temperatures and can be used to produce loose-fill insulation.  It is similar in appearance to loose-fill insulation made using another mineral, Mica.  Both of these were popular attic insulating material in the 1940's and used well into the 1960's.  They became less favored as newer materials were developed with superior insulating properties.  Perlite had very similar insulating properties although the minerals are replaced with glass. 

In 1990, the U.S. Environmental Protection Agency (EPA) closed vermiculite mining operations in Libby Montana because the deposit was shown to contain significant amounts of asbestos commingled with the vermiculite.  At the time, the EPA estimated over 80% of the world’s vermiculite production came from this one deposit.  Unfortunately, insulation marketed under the name Zonolite had been produced from ore from this deposit for decades.  Although not all Vermiculite contains asbestos, if this or any similar type of insulation is present, we recommend that you contact an insulation specialist to positively identify the materials used.  For more information, visit the EPA website and read the EPA fact sheet on vermiculite insulation or the EPA Vermiculite Insulation FAQ.


There are a number of ventilation issues that can be discovered in the attic.  The most obvious is the ventilation of the attic itself.  However, ductwork from bathroom and kitchen vents as well as the vent for the plumbing system may all run through the attic and be visible for examination. 

Attic Ventilation -

Proper attic ventilation can make your home more comfortable in the summer, reduce moisture levels and extend the useful life of your roof.  Many modern homes employ a system using vents in both the soffits as well as at or near the ridge to allow air flow through the attic.  As the air in the attic heats, it rises and exits through the upper vents drawing cooler air in through the soffit vents.  Additional airflow may be achieved by installing an exhaust fan near the ridge to help draw air through the attic.  Older homes were generally built with less attic ventilation and may only employ gable vents or windows. 

Black or gray mildew stains, or excessive moisture are all signs that air flow through the attic needs to be increased. 

Additional Ventilation -

In many homes, fans are installed in the bathroom ceiling to vent moist air and smells away from the living area.  Sometimes ventilation fans also appear in kitchens.  The fan should exhaust into ductwork that carries the air outside of the home.  A damper is used to insure that air only flows in one direction.  Exhaust systems that vent into the attic could be adding unwanted moisture to the attic. 

A home’s plumbing system requires venting as part of the waste system.  These vents allow the waste to properly drain, help prevent harmful sewer gas from entering the home, and are often observed running through the attic. 

Attic photo showing roof support structure and insulationBatt insulationLoose Fill Attic InsulationEPA stock photo of vermiculite insulated attic

Building Component Topics: Attics | Chimney | Electrical | Exterior | Foundation
Heating & Cooling | Plumbing | Roof | Safety Systems

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