Foam board insulation properties, R-values, fire hazards, inspection recommendations
Photo guide to identification of different building insulation materials
Properties of different building insulation products
Types & photographs of building insulation that does not normally contain asbestos
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This page illustrates and describes properties of various types of foam board building insulation. We give advice to owners and inspectors regarding the R-values, fire safety, insect resistance, and mold resistance of foam building insulation products.
We provide photographs and descriptive text of asbestos insulation and other asbestos-containing products
to permit identification of definite, probable, or possible asbestos materials in buildings.
Solid Foam Product Insulating Products - Rigid Polystyrene, Polyurethane, Polyisocyanurate Insulation products will not contain asbestos fibers and most of these products are rather mold resistant, possibly because of their chemistry or because closed-cell foam insulations simply do no take up and hold the moisture that is required for active mold growth on or in building insulations or surfaces.
What are the Insulation R-Values of Foam Insulation Boards?
Expanded, extruded, and cut bead polystyrene insulation products have an R-value of about 4.0 per inch of thickness. Typical exterior foam board building insulation sheets have an R-value of 2.64 per inch. See POLYSTYRENE FOAM INSULATION for details.
Expanded polyurethane building insulation products have an R-value of about 5.0 per inch of thickness. See URETHANE FOAM Deterioration, Outgassing for a discussion of foam board outgassing and R-value deterioration.
Expanded polyurethane insulation expanded using the refrigerant gas has an R-value of about 6.25 per inch. See URETHANE FOAM Deterioration, Outgassing for a discussion of foam board outgassing and R-value deterioration.
Polyisocyanurate insulation products have an R-value of about 7.04 per inch. See Icynene Foam Spray Insulation for details.
See INSULATION R-Values & Properties for R-value and other properties of nearly all historic insulating materials as well as contemporary building insulation products. [ASHRAE Fundamentals Handbook.]
Foam insulation board should not be left exposed in building interiors. While many modern foam insulating products do not themselves readily support combustion (that is they don't catch fire and burn alone) they may give off thick acrid or toxic black smoke in a fire, making it difficult to safely exit the burning building.
In the photograph at left, foam insulating board is shown on a garage ceiling below a second floor bedroom - this material should have been covered with fire rated drywall to meet local building code specifications for fire safety.
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06/07: thanks for photographs of transite asbestos heating ducts, courtesy of Thomas Hauswirth, Managing Member of Beacon Fine Home Inspections, LLC and (in 2007) Vice President, Connecticut Association of Home Inspectors
Ph. 860-526-3355 Fax 860-526-2942 beaconinspections@sbcglobal.net
Fiberglass: Indoor Air Quality Investigations: Health Concerns About Airborne Fiberglass: Fiberglass in Indoor Air from HVAC ducts, and Building Insulation
Enviro-Scare: Electric Power Lines, Electromagnetic Fields, Cancer Risk, & "Enviro-Scare" - The Normal Curve Cycle of Public Fear of Environmental Issues
Dust from the World Trade Center collapse following the 9/11/01 attack: the lower floors of this building contained spray-on fire-proofing asbestos materials.
Asbestos Information Links: Asbestos Detection, Testing, Recognition, Hazards, Field Photos, and Information Sources, including
health-related links such as legal services and information about mesothelioma and other cancers.
Asbestos Identification and Testing References
Asbestos Identification, Walter C.McCrone, McCrone Research Institute, Chicago, IL.1987 ISBN 0-904962-11-3. Dr. McCrone literally "wrote the book" on asbestos identification procedures which formed
the basis for current work by asbestos identification laboratories.
Stanton, .F., et al., National Bureau of Standards Special Publication 506: 143-151
Pott, F., Staub-Reinhalf Luft 38, 486-490 (1978) cited by McCrone
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The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.