Like it or not, spray polyurethane foam (SPF) insulation and the “Green” movement are here to stay. Unfortunately, there are homes where the application has led to reports of nuisance odors and occupant sensitivity. These occupant related complaints have led to a rise in SPF insulation investigations by many who have little understanding of SPF insulation and how sealing yourself in with SPF can negatively impact the indoor environment even when correctly applied.
When it comes to the investigation of nuisance odors associated with the application of spray polyurethane foam SPF insulation, I’ve found that most of the investigations typically involve little more than varied attempts at trying to chemically associate the odor with the off-gassing of the SPF.
I’ve been assessing spray polyurethane foam insulation SPF for many years on too many properties in too many states to list. I’ve assessed a dozen or so product lines both closed and open cell for manufactures, builders, homeowners, and applicators. The properties ranged from universities, community centers, offices, homes, both new construction and retrofit applications.
In my experience, SPF investigations can be categorized in three distinct categories. The first two seem to be the primary areas of SPF investigations. The first category is simply miss-applied SPF, the second is presence of pre-existing or recently introduced contaminants and the third would be occupant exposure and sensitization during SPF application.
By using these three assessment categories, I have had great luck in identifying the catalyst of the odor and associated complaint. It has also helped raise awareness that it’s not always the SPF.
The First Category – Category 1 Miss-Applied SPF Insulation Category
These nuisance odors are directly associated with incorrectly applied SPF insulation and can be addressed by either correcting the areas of misapplied foam or by removing and re-insulating the areas. Misapplied includes improper ventilation during the application, incomplete application, off ratio application, and also includes the SPF in direct contact with recessed can lights in the attic, keyless light fixture bulbs, dryer vents, and/or furnace and chimney flues, all of which can heat the SPF and cause a tremendous amount of chemical odors.
Category 1 is relatively cut and dry and requires the onsite inspection of the SPF and the collection of no air samples. The inspection of the foam and the determination of correct and complete installation is a critical first step.
I‘ve been on SPF insulation investigations where Consultants or Indoor Environmental Professionals (IEP’s) who were hired to assess the SPF insulation never actually looked at the SPF insulation. Many never even made a site visit. They simply hire someone local to collect a few air samples for volatile organic compounds, VOC’s. Many have no knowledge of how to assess the correct or complete installation of the SPF insulation. Many IEP’s show up with all manner of air sampling equipment and begin and end their investigation with the collection of air samples intending to identify the chemical signature of misapplied SPF insulation. There has been enough review of collected air samples to show that’s just not going to happen.
For all who want to conduct SPF insulation inspections, start with understanding what correct and complete installation is according to the manufacturer who produced the foam you’re inspecting. Know and understand the whole house design considerations with SPF. Be open minded and scientific with your assessment and don’t automatically assume it’s the SPF.
Consultants and IEP’s assessing homes with reported SPF related complaint must remember the substantial change that has just been made to the home. These changes alter the performance and conditioning of the home. The Consultants and IEP’s must take into consideration the ventilation and conditioning of the sealed attic.
A sealed home must have a design consideration for the ventilation of the living space and for moving air through the newly acquired real-estate of the attic. Many of the top SPF manufactures include language similar to the following. “All buildings insulated, and air sealed with SPF Insulation must be designed to include adequate mechanical ventilation and outdoor air supply for optimum IAQ (Indoor Air Quality). For mechanical ventilation see ASHRAE Standard 62 – Ventilation for Acceptable Indoor Air Quality or any other acceptable good engineering practice.” That’s a solid statement.
The Spray Foam Coalition of the ACC Center for the Polyurethanes Industry also states on page 23 of their Guidance on Best Practices for the Installation of Spray Polyurethane Foam, “SPF applications typically improve air sealing of the structure and it is important for building owners to understand how this impacts the overall building and the potential need for new or additional ventilation.”
In addition, the Spray Foam Coalition of the American Chemistry Council, ACC Center for the Polyurethanes Industry also states on page 24 of their Guidance on Best Practices for the Installation of Spray Polyurethane Foam in the Retrofitting Attics section under the heading of HVAC Systems (Attics);
“The contractor and the homeowner should be aware that retrofitting an existing attic by employing an unvented attic assembly technique can result in the existing HVAC system becoming “oversized” in relation to the new demand. This situation is of special concern in the southern and coastal climate zones where the HVAC also serves to reduce or otherwise manage moisture levels of buildings in order to improve comfort and prevent moisture related problems, such as mold and mildew. If an existing HVAC becomes “oversized” due to the increased thermal efficiency of the unvented attic assembly, the HVAC system may begin to short cycle, or to quickly turn on and off, as it works to manage temperature. This short cycling of the HVAC system may have negative impacts on the comfort and efficiency of the building and possibly on the lifespan of the system. Involve an HVAC consultant to adapt the system to the new, more efficient building envelope associated with the spray foam retrofit.”
Far too often the homes issues are directly related to inadequate cleaning of the attic, no design consideration for conditioning the attic, and not meeting the minimum ventilation rate set by ASHRAE Standard 62 – Ventilation for Acceptable Indoor Air Quality.
The Second Category - Category 2 Pre-Existing or Recently Introduced Contributors
This category cannot be stress enough to the professionals that are investigating SPFI. This category runs the gamut and can include some rather odd contributors to occupant discomfort and nuisance odors that become much more concentrated when the SPFI is installed. These include the HVAC system, air exchange rate, storage of materials in the now sealed space, insect and or rodent activity, routine pest control applications, the previous insulation condition and material, proper ducting of kitchen and bath fans. The possibilities are endless, and all must be considered. Remember that what has accumulated in the attic is now semi-conditioned air that is shared with the attic and living space of the home.
For example, if the home is a 60-year-old ranch that had open cell SPF installed at the roof sheathing and the attic was not cleaned to help save a few bucks, the bath fans are ducted to the attic space, and the home once had a rodent issue that was treated with poisons. Well to say the least you have a huge list of contributors to occupant discomfort and nuisance odors. Most of the SPF insulation investigations I am called in to review all of these issues were overlooked simply because of the recent application of SPFI.
It’s not necessarily the SPF insulation that’s producing the odor or contaminates that are causing occupant discomfort, but the SPF insulation is what eliminated the natural ventilation of the attic which prevented the odors and contaminants from accumulating in the home. The SPF insulation has now trapped the odors and contaminants within the conditioned space of the home which now includes the sealed attic. In many cases, the home is no longer meeting the minimum ventilation rate and is accumulating VOC’s from daily use products.
Many of the homes we consult on are blower-door tested and don’t even come close to the minimum ASHRAE air exchange rate. That attic air is now a part of the occupied space and has 60 years of accumulated who knows what. Easily it could include the accumulation of dust, debris, fiberglass, rodent and insect activity, prior application of pesticides, maybe even vermiculite. Which we have found within sealed SPF attics.
This is a huge aspect of an SPF insulation investigation that I find all too often overlooked. As a professional investigating SPF insulation, you have to ask questions beyond the obvious who was the evil SPF insulation manufacturer.
You have to ask relevant questions such as;
- “What is the condition of the new sealed attic space?”
- “What have the occupants been sealed in with?”
- “How is the ventilation rate being met?”
- “How is the conditioned space actually being conditioned?”
- “Is there any design consideration for controlling the sealed attic space?”
Sometimes it’s best to keep it simple, particles, pathway, and pressure. Remember to keep an opened mind; it’s not always the SPF insulation.
Many new construction homes have SPF insulation. Most will have outdoor air supply but many wont have any means of dehumidification. The introduction of the hot humid outdoor air in many climate zones will inevitably lead to the closing of the outdoor air supply. Tis will then lead to the accumulation of the daily use VOC’s.
Sometimes as Consultants and IEP’s we’re hired to provide a very specific service. SPF insulation investigations are very specific. However, are we hired to help the homeowner identify what in their home may be contributing to their symptoms or are we there to prove the homeowner hypothesis that it’s the SPF insulation?
IEP’s often go in with blinders on and lose focus on the true intent of the investigation which in my opinion should be “What is contributing to occupant discomfort and complaint?” The IEP should approach the home as a system and be open to all potential contributors to occupant complaint. The chief characteristic that distinguishes the scientific method of investigation from other methods of investigation is that scientists seek to let reality speak for itself, supporting a theory when a theory's predictions are confirmed and challenging a theory when its predictions prove false. Scientific investigation is generally intended to be as objective as possible in order to reduce biased interpretations of results. This is often overlooked when the IEP conducts an investigation focused on making the evidence support their hypothesis without objective challenge.
IEP’s must remember that while the SPF insulation may be the issue unless you can say there are no other issues within the home you have not completed your investigation you have just begun.
The Third Category – Category 3 Sensitization Due to Exposure
This category includes all occupants who have become sensitized or allergic to the odors given off from SPFI. With sensitization occupants have either re-entered the property shortly after the foam is applied, well before the manufacturer recommended re-occupancy time of 24 to 48 hours while the SPF insulation is still curing and off-gassing, or in the most severe cases of occupant sensitivity the exposure was actually took place during the application of the SPF insulation.
Sensitization of the occupants can be a result of many issues such as occupants that don’t want to spend the money for a hotel stay, early re-entry or occupancy, the curious application observer, to the painfully stupid like the builder above. However, occupant sensitization can also be the result of the lack of proper ventilation during the application. Venting of the off-gassing of the SPF insulation during application is critical and often not conducted at all. In all cases of occupant sensitization that I have been involved with the SPF insulation application was not properly vented to the exterior which created a substantial accumulation of the off-gassing chemicals within the property. These trapped volatile organic chemicals VOC’s are what sensitizes the occupants who have either re-occupied too early or were present during the SPF application.
Sensitization occurs when the occupants are overexposed to the trapped volatile organic chemicals VOC’s and become sensitized. From that point on, any exposure to even a minute amount of the chemical causes a reaction. The process of sensitization can make a home unlivable for people who become sensitized.
Homes that have improper ventilation during the application process of the SPF insulation are also included in the misapplied category and almost always have identified areas of misapplied SPF insulation (SPFI).
This category is unique in that any attempt at reducing the occupant’s exposure to the SPF insulation that they are now sensitized to may not be of any relief. I have had no luck in providing sensitized occupants relief from the home they are now sensitive to. I have been involved in everything from the introduction of outdoor air through a pre-filter and dehumidifier to control the temperature, humidity, particles, path, and pressure to full removal of the SPF insulation. Unfortunately, the sensitized bell just can’t be un-rung.
My advice to clients that have become sensitized to the SPF due to exposure during the application or as a result of premature occupation is to establish the installed condition of the SPF, improve the homes ventilation design to accommodate the SPF sealed home, and to sell the home once the improvements are complete.