Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
INSULATION INSPECTION & IMPROVEMENT
ACOUSTICAL SEALANT CHOICES
AIR LEAK MINIMIZATION
ASBESTOS IDENTIFICATION IN BUILDINGS
BASEMENT CEILING VAPOR BARRIER
BASEMENT HEAT LOSS
BRICK LINED WALLS
BRICK VENEER WALL AIR LEAKS
BUCKLED FOUNDATIONS due to INSULATION?
CATHEDRAL CEILING INSULATION
CATHEDRAL CEILING VENTILATION
CEILINGS, DROP or SUSPENDED PANEL
DEW POINT TABLE - CONDENSATION POINT
DUCT INSULATION, ASBESTOS PAPER
FIBERGLASS PARTICLE CONTAMINATION
Fiberboard Insulation Sheathing Mold
FIBERGLASS INSULATION MOLD
FIREPROOFING ASBESTOS SPRAY-ON
FRAMING DETAILS for BETTER INSULATION
FRAMING DETAILS for DOUBLE WALL HOUSES
FRAMING METAL STUD PERFORMANCE
FREEZE-PROOF A BUILDING
HEAT LOSS in BUILDINGS
HEAT LOSS PREVENTION PRIORITIES
HEAT LOSS R U & K VALUE CALCULATION
HOUSEWRAP AIR & VAPOR BARRIERS
HOUSE DOCTOR, how-to be
HUMIDITY LEVEL TARGET
ICE DAM PREVENTION
INSULATION AIR & HEAT LEAKS
INDOOR AIR QUALITY & HOUSE TIGHTNESS
INSULATION CHOICES & PROPERTIES
INSULATION FACT SHEET- DOE
INSULATION IDENTIFICATION GUIDE
INSULATION INSPECTION & IMPROVEMENT
INSULATION LOCATION - WHERE TO PUT IT
INSULATION R-Values & Properties
LEED GREEN BUILDING CERTIFICATION
LOG HOME ENERGY EFFICIENCY
MOLD in FOAM INSULATION, RESISTANCE
MOISTURE CONTROL in BUILDINGS
NOISE / SOUND DIAGNOSIS & CURE
RIGID FOAM USE INDOORS
SHEATHING, FOIL FACED - VENTS
SLAB INSULATION, PASSIVE SOLAR
STAINS on & in BUILDINGS, CAUSES & CURES
STRAW BALE CONSTRUCTION
STUCCO WALL METHODS & INSTALLATION
STUCCO OVER FOAM INSULATION
SWEATING (CONDENSATION) on PIPES, TANKS
Thermal Expansion Cracking of Brick
THERMAL IMAGING, THERMOGRAPHY
THERMAL MASS in BUILDINGS
THERMAL TRACKING Indicates Heat Loss
TRUSS UPLIFT, ROOF
VAPOR BARRIERS & CONDENSATION in BUILDINGS
VENTILATION in BUILDINGS
WALL CONSTRUCTION BARRIER vs CAVITY
WIND WASHING INSULATION At EAVES
WINTERIZE A BUILDING
This article discusses the question: are there any health hazards associated with applying rigid foil-faced insulating foam (polyisocyanurate insulation) on the interior side of walls? Sketch at page top and accompanying text are reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
The question-and-answer article about the indoor use of foil faced insulating foam found just board below paraphrases, quotes-from, updates, and comments an original article from Solar Age Magazine and written by Steven Bliss.
Is Foil Faced Polyisocyanurate Foam Insulation Hazardous when Used Indoors?
Are there any health hazards associated with applying rigid foil-faced polyisocyanurate insulation on the inside of the existing walls of a living space?
I am aware that these insulations give off toxic gases as they burn. The question in my mind is whether they are safe on a day-to-day basis within the building envelope with an air change rate of say 0.75 ACH per hour? -- R.H. Mendocino CA
Our photograph (above left) shows Celotex Super Tuff-R polyisocyanurate insulating board used indoors.
Rigid polyisocyanurate insulation is foamed from freon gas, a fluorinated hydrocarbon often used as a refrigerant and until the early 1980's, as a propellant in aerosols. [Currently non HFC gases are used for foam insulation production --DF] The earlier-used Freon gas family and modern refrigerants are inert gases and are considered non-toxic, except in very high concentrations of over 1000 ppm [at which point even an inert gas can cause asphyxiation].
The small quantities of gas that will be released from this foam insulating board [until it has "cured" and stopped outgassing] by diffusion or rupture are not considered a health hazard by the several health authorities we contacted. The upper-limit service temperature for this type of foam is 250 degF.
In uncontrolled combustion, all flammable building materials release high levels of toxic fumes. The National Fire Protection Association (NFPA) recommends that all insulation products be contained behind drywall or a suitable fire retarder. A check with your local building officials is almost certainly going to confirm that foam insulation products may not be left exposed in the living area.
In our sketch at page top you will see that the solid foam insulating board in that illustration is placed on the building interior wall surface, but it has been covered with furring strips and then drywall. The furring strips provide a dead air space, increasing the wall's R-value, and the space is in some conditions also used for routing wiring.
The hazard with foam insulation products is of production of toxic fumes or smoke release during a building fire, not outgassing during normal building conditions.
Readers should also see POLYSTYRENE FOAM INSULATION, INSULATION LOCATION for PASSIVE SOLAR FLOOR SLAB and also RIGID FOAM USE INDOORS. Readers should also see FLOOR, CONCRETE SLAB CHOICES for a discussion of choice of finish floor materials to preserve use of thermal mass of a concrete floor slab. Readers interested in basement insulation improvements should also see INSULATION LOCATION for BASEMENT WALLS and BASEMENT HEAT LOSS.
For more general energy savings advice see ENERGY SAVINGS PRIORITIES, and our insulation home page at INSULATION INSPECTION & IMPROVEMENT. If you are going to insulate under a basement or grade-level concrete slab floor, be sure to read SLAB INSULATION, PASSIVE SOLAR. Finally, readers considering adding insulation inside or outside a basement foundation wall should see POLYSTYRENE FOAM INSULATION as well as BUCKLED FOUNDATIONS due to INSULATION? Contact us to suggest text changes and additions and, if you wish, to receive online listing and credit for that contribution.
Here we include solar energy, solar heating, solar hot water, and related building energy efficiency improvement articles reprinted/adapted/excerpted with permission from Solar Age Magazine - editor Steven Bliss.
Frequently Asked Questions (FAQs)
No FAQs have been posted for this page. Try the search box below or CONTACT US by email if you cannot find the answer you need at InspectApedia.
Questions & answers or comments about using polyisocyanurate foam insulation in buildings
Question: using polyisocyanurate form insulation in the roof (ceiling) of our out door sauna
(Aug 6, 2011) Diane said: Hello great article. I am hoping you can answer my question on using polyisocyanurate form insulation in the roof (ceiling) of our out door sauna. We are planing to use them in ceiling then cover them with foil as a bearier then apply the tonge and grove cedar to the ceiling. Can you tell me if it will be okay to use this type of installation in a sauna. My concern is the heat generated by the sauna and off gasing. Please let me know if it is safe to use this product. Thanks for your assistance.
(Aug 7, 2011) Diane said: Thanks DanJoeFridman for your opinion and information. I will send this web site to our builder to review. And we will be installing a metal roof for the sauna. But I am still unsure about the off gasing of this product. Do you know anything about that aspect of this product?
Reply: Air leaks as a moisture source in roofs versus need for a vapor barrier
DanJoeFriedman (mod) said:
Diane my OPINION is that the installation of a foil vapor barrier forms a perfect vapor barrier - foil has a perm rating close to zero - except if it's cut or penetrated. (It's probably fine for the ceiling covering nails to penetrate the foil where it crosses over ceiling joists).
There are fire code and fire barrier standards that make sense to apply to any occupied building, not just your home, but also outbuildings like a sauna. Check with your building department to ask if the fire barrier formed by the T&G cedar ceiling is adequate to meet the code requirement for covering foam insulation. If it's not, you can add a layer of fire-rated drywall before installing the ceiling boards.
Finally, while I like the energy efficiency of foam insulation installations, I'd take extra care to inspect and maintain the building roof - from outside. A foam-insulated ceiling without ventilation and without inspection access (say a foamed cathedral ceiling) can't be inspected for leaks from inside. Any damage to the roof that causes a leak can result in very extensive damage to the insulated ceiling before you'd notice it indoors.
On a recent foam-insulated ceiling project we opted for a standing seam metal roof for these reasons.
Try the search box just below or if you prefer, post a question or a comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.