On top of all the other problems anyone building a new house is bound to encounter, Carolyn Farrow has a concern that outweighs all others: her daughter’s health.
“Our toddler has a lot of chemical sensitivities and respiratory issues and insulation decisions are completely overwhelming me,” she writes in a post at GBA’s Q&A forum. “I can’t find any contractors that I trust.”
The allergist and pediatrician treating Farrow’s daughter say she could react to virtually any type of insulation, and they are not comfortable making any specific recommendations.
“They both suggested finding an insulation contractor that I trust and is not just trying to sell me what makes him the most money,” Farrow says. “So, that is what I am trying to do. I have researched everything and nothing seems 100% safe. What are we supposed to do? Not insulate our home?
“I am not asking an insulation specialist to make medical claims or ensure the safety of materials,” she continues. “But I am looking for an insulation specialist that is informed about their products and makes an effort to choose the safest products possible.”
Farrow’s quest is the subject of this Q&A Spotlight.
Concerns are misplaced
Given that no one seems to know exactly what will cause a negative reaction, Nate G replies, there’s no real way to avoid potential risk. Even so, as long as the insulation is installed correctly and contained in the walls of the house, there’s probably not a lot to worry about. Farrow is, he continues, probably “barking up the wrong tree” by focusing her concerns on insulation. A greater threat are the other building materials and furnishings that affect air quality.
“The products that would be the ones to worry about are the wall paints, flooring, furniture, and HVAC system,” Nate adds. “Choose materials that are more inert and preferably made from rocks and dirt. That means tile, stone, and plaster, things like that.”
He suggests avoiding Chinese-made furniture that could be loaded with formaldehyde, and choosing solid-wood furniture instead, especially if it’s old. Older objects have had more time to off-gas potential contaminants, and building the house out of masonry covered inside with plaster might help. Among other suggestions: a robust heat-recovery ventilator with a high-efficiency filter, an electric range, no wood-burning appliances, and no carpeting.
“But honestly, the best thing in your situation might be to find a good old house. Old houses were made with durable materials that have long-since off-gassed everything nasty,” Nate says. “There’s no worry about construction dust or any of the other problems caused by construction. New construction — even with mostly inert materials — is going to create more health hazards than an already-existing older house might…
“The deeper problem is that you are fixating on something that, in the scheme of things, is relatively unimportant. Your daughter’s health is going to be far more seriously impacted by the quality of the air and finish materials inside the house you are building than by the material of the insulation inside the walls,” Nate continues. “That’s why I’ve recommended that you spec an air-filtering HRV, a heating system that doesn’t blow air, inert finish materials that don’t off-gas anything, and to avoid combustion appliances, in particular avoiding a gas range.”
Some types of insulation are inherently safer
It’s Farrow, not the insulation contractor, who will have to make the call, says Dana Dorsett, and with that in mind, there are certain types of insulation that come with fewer health concerns.
Damp-spray cellulose, for example, is made of ground-up newspapers and borate fire retardants that have very low toxicity. Other than what might be in the residual inks, there’s not much there to hurt Farrow’s daughter, and if she can tolerate fresh newsprint, this might be a good option.
Rock wool batts, Dorsett continues, have small amounts of binders, most of which are cooked out of the insulation as it’s processed, with very little off-gassing when the insulation is finished. Most fiberglass and spray foam products, on the other hands, will produce some off-gassing. Rigid foam insulation contains fire retardants that might be a concern, but foil-faced versions are gas-tight and will off-gas only at panel edges.
“The insulation is all on the other side of what should be an air barrier which limits the amount of potentially harmful materials getting into the house,” Dorsett says. “But making that perfect air barrier on the interior isn’t usually the insulation contractors’ job. You could make it part of their job if you insisted on a 2-mil nylon air-barrier and vapor retarder (Certainteed MemBrain), detailed for airtightness prior to hanging the wallboard. That job could be performed either by the insulation contractor, or some other subcontractor, but it needs to be inspected carefully for leaks before installing the wallboard.”
But, like Nate G, Dorsett also believes it is the materials inside the living space that should be of the greatest concern, not the insulation itself.
Aaron Gatzke, however, isn’t so sure. He writes that his wife developed “multiple sensitivities” after CertainTeed fiberglass insulation was installed in their house. “She was exposed to the insulation dust one day while sitting outside,” he says, “but we also noticed that the insulation itself had an extremely strong odor from the new organic binder they used to replace formaldehyde.”
Problems cropped up even after the insulation was sealed behind 6-mil polyethylene, tape, and acoustic sealant.
“You should also prepare for a long period of off-gassing,” Gatzke writes.
Consider hiring an energy consultant
Steve Knapp writes to say one of his goals in building a new house was the best possible indoor air quality, and after struggling with the choice of insulation he chose foam. If he were to do it all over again, he’d be looking at either cellulose or exterior insulation.
From what Farrow has said, it sounds as if it might be too late to consider exterior insulation, so sealing the insulation behind the drywall, as others have suggested, now looks like the best course. That, plus an effective ventilation system will help.
“One last suggestion,” Knapp says. “Consider hiring an experienced energy consultant to review the work being done on your home and advise you on strategies for achieving your healthy house goals.”
On her own, Farrow will never be able to do the research guaranteeing a healthy house, Knapp says, and even then it might not be enough to prevent the serious health issues Farrow has described in her daughter.
He adds: “Also be aware that doing all the ‘right things’ to construct a healthy house may not solve your daughter’s health issues. When my house was nearly completed, I finally received an accurate diagnose to a lifetime’s worth of health problems. With that knowledge, I learned that building a healthy house was not going to affect my condition in any significant way.
“Getting healthier was going to require a completely different strategy,” Knapp adds. “At the same time, I still thought it made more sense to live in a healthy house than one filled with a toxic stew of man-made chemicals. Most people spend 80 percent of their lives in buildings. Why inhabit ones that are going to damage your health in avoidable ways?”
Our expert’s opinion
Here’s what GBA technical director Peter Yost has to say:
It sounds as though Carolyn Farrow has interior building material selections under control in terms of the selection of “healthy” materials. But since Health Product Declarations (HPDs) have not been mentioned, it’s seems important to do so now. HPDs are to disclose product ingredients and any health hazards associated with them. HPDs are set up to pretty much parallel nutrition labels on food products.
Our company, BuildingGreen, has done a lot of work on HPDs; here is on how to use HPD labels. Our BuildingGreen-approved building product directory relies heavily on HPDs for many interior components. But to date, few, if any, insulation materials have HPD labels.
For cavity insulation, you have two primary choices in materials: blown or batt insulation. There are quite a few BuildingGreen-approved insulation materials, but I would call out the following because they do not have potentially-problematic blowing agents or flame retardants:
- . This is a formaldehyde-free blown insulation which I have used on projects with owners concerned about their children’s health, to good effect. The binder is polyester-based; check in with your allergist on this constituent of the insulation.
- . This is another formaldehyde-free fiberglass insulation but it is dry-blown with no binder; it is kept in place by a non-woven fabric facing. Optima is Greenguard Gold certified.
- , an inert, stone-based fiber with cured urea extended phenolic formaldehyde binder. Check with your allergist on this binder. Comfortbatt is Schools and Children-Greenguard certified.
- . This insulation has a formaldehyde-free bio-based binder carrying the Greenguard Gold certification. There certainly are other brands of formaldehyde-free fiberglass batt insulation, but I am calling out this one because the manufacturer also has an air-sealing system, , which uses a two-part latex system. Check with your allergist about latex-based products.
- insulation. This is another formaldehyde-free batt insulation certified as Greenguard Gold that can be coupled with the Knauf air-sealing system, , an acrylic-based sealant. Check with your allergist about acrylic-based products.
BuildingGreen is a big fan of cellulose insulation but I am not including it because of concerns that some chemically sensitive people have expressed over borates, which are used as a flame retardant, and with newsprint ink. I also did not include a host of products that may work well, but are much less widely available than the above.
And maybe these go without saying, but let me add:
- Any insulation is only as good as the quality of its installation and some of these products — particularly the batts — are notoriously difficult to install at top-performance level.
- As others have noted, insulation may be the least of your worries, particularly if you employ a continuous interior air barrier system.
- Along with interior material selections, furnishings — window treatments, rugs, stuffed couches, mattresses, bed linens — can have a big impact on indoor air quality.
- The mechanical ventilation and filtration systems also play a big role in maintaining indoor air quality.