As I write this article, it’s 10:10 AM, October 10. Outdoor temperature is 78 degrees, with 98% humidity! Yes, this is a bit unusual for this time of year… but as my daughter Savannah is fond of saying, “Dad, it is what it is!”
And because she is right, you must be aware of a recent scientific study that reveals a major issue that can develop in spray foamed, encapsulated (sealed) attics.
The second concern, is one born out of the post-project reviews with homeowners after hundreds of sealed attic encapsulations.
This is so important, I have dedicated this blog article entirely to these two issues. Here we go!
Concern # 1. Spray foam insulation WILL tighten your house. “That’s what we want, Bob! Seal the house, stop the drafts and bugs…”
Being a spray foam contractor has taught me a new term in my daily vocabulary: “Unintended Consequences”.
As a Home Performance Contractor, we have learned (and experienced) that our actions employed on a house generally will positively or negatively affect other systems, like the performance of your Heating and AC; Indoor Air Quality (smells & humidity levels), Changes in Comfort from Zone to Zone, etc.
A quick story: 3 years ago we sprayed the subfloor of Ms. Wilson’s home, using closed-cell spray foam. Two years later, she called in July and asked to have her attic encapsulated with spray foam. We installed open-cell spray foam in her attic. One week later I receive an email from Ms. Wilson, “Bob, we are miserable. The AC won’t shut off, but the house feels muggy inside.”
I arrived at the house, and sure enough, the problem was “Unintended Consequences”.
After sealing both horizontal planes of the house (floor & roof) with spray foam, the house was sealed like a Tupperware, and pre-existing HVAC problems were now magnified.
Here’s what I found:
- Not enough Return airflow, it was grossly out-of-balance.
- The weight of the furnace had caused the bottom edge of the Return Plenum to break away from the furnace, resulting in a nasty 2” wide gap the entire width of the unit.
- SUPPLY Air temperature was 79 degrees. (Remember, this is during hot AC season!)
- Just as important, NO condensate was dripping from the condensate pipe.
Expecting an HVAC problem, I had a put one of our portable dehumidifiers in the truck with me, and I quickly set it up in their home. 24 hours later, Ms. Wilson sent me an email, “Bob, the house is 200% more comfortable. The improvement in comfort is amazing.”
They added RETURN vents, properly supported the furnace, sealing the huge RETURN plenum leak, and corrected the refrigerant level, (resulting in colder airflow).
(On a side note: She had a 14 year relationship with a prominent Atlanta HVAC company, with annual maintenance contracts. Before contacting me with her 1st email, she called them. Their answer to her problem was to sell her a smart thermostat, and when that didn’t help, they wanted to install a whole-house dehumidifier. Luckily, she contacted us, and only spent a fraction of the $, and solved her problem.)
Spray Foam is an air barrier. Meaning, we are tightening your home.
BEWARE of the Unintended Consequences!
Potentially, in some homes, your Indoor Air Quality may suffer, because the house is tighter, the HVAC runs less often, and pre-existing smells and relative humidity inside the living space are now concentrated at higher levels.
Concern # 2. Due to the high Relative Humidity in our region, moisture can accumulate in the attic.
Here are tips for managing moisture swings:
- Add a source of conditioned airflow to the attic area.
- Install pass-through ventilation in the ceiling.
- Use a small exhaust fan to purge moisture-laden air from the attic.
- Install a wireless hygrometer to monitor attic conditions.
Installing spray foam insulation in your home is a premium upgrade. Protect yourself from unpleasant surprises and unintended consequences by having a conversation about these two concerns with one of our Comfort Pro specialists today at Bird Family Insulation... Call us at 404-538-9168! We're here to help.
Stay tuned for my follow-up blog!