A few years ago, I wrote about the topic of high humidity in spray foam attics. When you encapsulate the attic with spray foam insulation and don't do anything to condition the air in the attic, the humidity can get very high. It also stratifies, with the highest relative humidity near the ridge.
Mold and mildew can begin growing behind the insulation which can go unnoticed until it's already become a huge problem. This often happens when the spray foam isn't installed correctly and space is left between the insulation and the wall, which allows moisture in and gives mold the perfect place to grow, unfettered.
There are many variables, but simply stated, if we keep the surface the humid air contacts warm, it tends not to condense. We do this by insulating with spray foam. This only works because spray foam is an air barrier material and since it is, the spray foam also controls air from passing through it.
Insulation has a sealing superpower and doesn't let moisture get in your home, thus preventing water damage and high humidity levels. Homeowners also install insulation for condensation control.
When you encapsulate the attic with spray foam insulation and don't do anything to condition the air in the attic, the humidity can get very high. It also stratifies, with the highest relative humidity near the ridge.
What causes high humidity in a house? High humidity in a house can be caused by many things, but the biggest reason is poor ventilation—in other words, air isn't being circulated properly, which causes the air in your house to become stagnant and humid. The other major reason? Too much air exchange with the outside.
DON'T use expanding foam around outlets and recessed can lights. In the quest for a draft-free home, it's natural to want to add some insulation around electrical outlets, but expanding foam might not be the best type of insulation there.
Excess humidity can be caused by many factors such as poor ventilation, roof leaks, heating sources, and excessive insulation. Controlling this excess moisture from your attic is crucial for your health and safety.
In fact, when done correctly and professionally, spray foam insulation can actually increase the value of your home. This type of insulation adds value to any residential property by providing superior energy efficiency, durability, soundproofing capabilities, and more.
Adding spray foam insulation in potential problem areas is a great way to insulate your home and goes a long way towards mold prevention. It is mold-resistant because it expands when it gets wet, meaning there's no room for mold or mildew!
It can be badly installed
The spray foam roof insulation industry is unregulated and if isn't installed correctly or sprayed in a roof space that is unsuitable, such as one with a condensation problem, it can lead to rot. And it shouldn't be sprayed over cables, which could lead to overheating.
The Spray Foam has an Odor and Off-Gassing
Another issue is potential off-gassing that can cause breathing problems or other adverse health effects, according to the Environmental Protection Agency. While all spray foams have an odor, not all have issues with off-gassing.
Yes, attic ventilation is necessary even when using spray foam insulation. Spray foam insulation forms a tight seal around gaps and cracks, preventing air and moisture from entering the attic.
Note that not all spray polyurethane foams require thermal or ignition barriers. Seal any penetrations from the home into the attic through the attic floor. Provide conditioning, dehumidification, or controlled ventilation to the attic. Ensure the home has good ventilation.
So rather than having an attic operating at 120°F or higher applying a heat and moisture load above the living space, a sealed, unvented, semi-conditioned attic provides temperatures that are typically within eight to 12 degrees of the living space, or approximately 80°F to 90°F at the hottest part of the day.
Yes, you can sleep in your house after installing spray foam. However, the curing time for spray foam should be at least 24 hours after installation.
Both types of spray foam insulation can last anywhere from 80 years to 100 years, with closed cell spray foam having a slight edge in terms of durability. For most families, this represents the lifetime of the house and then some!
Some of the spray foam alternatives that you can find in your area include: Cellulose Insulation. Mineral wool insulation. Fiberglass batting or roll insulation.
Let's talk about what humidity levels you should keep in your home year-round, and different techniques to do so. Ideal in-home humidity levels should hover around 45%. Anything under 30% is too dry, and over 50% is too high.
If the levels are off, whether too high or too low, you face structural damage to your home as well as potential health issues. Comfortable levels of humidity range between 30% and 60%, however, the ideal humidity level, according to ASHRAE, is between 45% and 55%. Anything above 55% is considered to be high.
Do you feel like you're never comfortable at home, even though the AC reaches the set temperature? Your home's humidity level may be too high. A home should have a relative humidity of 30% to 60%. Above 60% and you have what's considered “high” humidity.
Weak insulation and drafty walls
If your home is letting in more moisture, it may be a sign that the insulation isn't doing its job or that the humidity has damaged the insulation.