Frequently asked questions
The questions that come up most on calls from around Mecklenburg County, answered plainly.
How long does an attic take?
Most single-family attics in Mecklenburg County are sprayed in one day. Preparation, masking and removing old material take longer than the foam itself, and the house needs to be vacated during application and for the re-occupancy period the manufacturer specifies.
Is the smell permanent?
No. Properly mixed and applied foam cures and is inert. A persistent odor weeks later points at a mix ratio or temperature problem during application, which is an installation failure rather than a property of the material, and it is difficult and expensive to remedy. That is the strongest argument for checking who is holding the gun.
Will my house be too tight?
A house can absolutely be sealed tighter than it can passively breathe, and in that case it needs mechanical ventilation, which is a normal and inexpensive part of the job. The failure mode worth avoiding is sealing the house and skipping that step.
Does it pay for itself?
Sometimes, over years, and anybody quoting you a specific payback month is guessing. The more honest reason people do this here is the comfort of the upstairs rooms and getting the ducts out of a 130 degree attic.
Is open cell worse than closed cell?
It is different, not worse. It costs less, gives less R-value per inch, and stays vapor open. For an attic roof deck with the headroom to spray it deep enough, that combination is frequently the better engineering choice as well as the cheaper one.
Do I need a vapor retarder with it?
In an unvented attic assembly in this climate zone, the humidity inside the house has to be managed one way or another, and depending on the assembly that can mean a vapor retarder coating or supplemental dehumidification. This is the detail that separates a careful installer from a cheap one.
Why is it so much more expensive?
Material density and chemical cost. You are buying roughly four times the material weight per cubic foot, and the raw chemical is more expensive to begin with. On a small area like a rim joist the difference barely registers. Across a whole attic it is thousands.
Does it really add structural strength?
It measurably increases racking resistance in a framed wall, which is a documented property of the material. It is a bonus rather than a reason to choose it, and it is not a substitute for engineered bracing.
Do the soffit vents get closed?
Yes. That is what unvented means, and it is the part that alarms people who were told all their lives that attics must breathe. A vented attic and a sealed attic are two valid assemblies, and the failure is mixing them by halves.
What about my gas furnace or water heater up there?
Atmospherically vented combustion appliances cannot stay in a sealed attic as they are. They get replaced with sealed-combustion units, or relocated. Any contractor who plans to foam around one and leave it is creating a safety problem.
Will my roof shingles run hotter?
Slightly, and the measured difference is small enough that shingle manufacturers generally do not treat an unvented deck as voiding a warranty. Confirm your specific warranty terms rather than taking anyone's word for it, including ours.
Is the test worth paying for on its own?
Frequently, yes. It is the cheapest way to find out whether your problem is insulation or leakage, and those have very different price tags attached.
Can a house be sealed too tightly?
It can be sealed tighter than it passively ventilates, and then it needs mechanical ventilation. That is a normal, inexpensive addition. The problem is never the tightness itself, it is tightening without ventilating.
Does old insulation always have to come out?
No. Dry, uncontaminated blown insulation on an attic floor can usually be added to rather than removed, which saves real money. It has to come out when it is contaminated, wet, or in the way of the assembly you are building.
What happens if there is knob-and-tube wiring?
Work stops until an electrician has dealt with it. Burying that wiring in insulation is a fire risk and a code violation, and it turns up more often than people expect in the older Charlotte neighborhoods.
Get a quote on your spray foam insulation
Call and tell us what is going on with your spray foam insulation and where the property is. You will get a straight answer on what it actually needs, from a licensed contractor working Mecklenburg County.
Call (980) 944-8316