Going in hot, dusty attics is something we do every day for our energy audits, all year round. While crawling around all those attics we get asked a lot “does my insulation need to be removed?” Many homeowners notice dust streaks around the registers or a thin film of powder on their dressers and tables and think their source of dust is from the insulation in the attic. Other homeowners feel like the dirty insulation becomes useless with age, especially after settling below the attic studs. This may be true, but does that insulation need to be removed? This is such a common question I decided to go into more detail on when attic insulation should be removed and when it can stay and the costs you can expect.
WHEN YOU SHOULD REMOVE YOUR ATTIC INSULATION
The Attic Was Infested With Rats Or Other Critters
The Insulation Should Be Removed When It’s Water Damaged
If you’ve had a roof leak or the condensation from your air conditioner has spilled out the drip pan onto your insulation, the insulation can hold moisture in for a long time and become a source of mold spores or mildew. It also will lose its effectiveness at slowing down the transfer of heat into your home once it’s wet. If a small area was affected, only that portion should be removed, the entire attic insulation does not have to be removed.
Roof rats are a common problem around neighbors with fruit trees and you may even hear them tapping around your attic at night. These critters will build nests and use the insulation as their home while seemingly multiplying and inviting all their friends to their new home. Rat urine and droppings are hazardous and need to be removed along with all the insulation in the infected areas. If a rat has been in an area, a trail of droppings will follow them. In this situation, the insulation should be removed and the attic disinfected before blowing new insulation in. When adding new insulation we prefer using cellulose blown in insulation because of the fire retardant chemical borate that’s used is also a rodent deterrent. If the attic has fiberglass loose fill insulation
Currently, it can be sucked out using an extraction machine. If the attic has fiberglass batts, they can be taken out by hand.
With Spray Foam Insulation To Air Seal The Attic
With Spray Foam Insulation To Air Seal The Attic
In hot dry climates like Phoenix, we typically use open cell spray foam and remove all the insulation from the attic floor (find how why here). Spray foam is an insulator and air sealant in one and with the attic ventilation completely closed off, there’s no more dust coming in from the outside. We want to create a completely sealed attic space which will naturally also improve the air quality of the home plus reduce your energy bills.
WHEN YOU DO NOT NEED TO REMOVE YOUR ATTIC INSULATION
There are times when we would not recommend removing your attic insulation that may contradict what some companies tell you but hear me out.
You Do Not Need To Remove The Insulation When It’s Just Old
Having old insulation may settle over time and you may be shocked to see the studs of your attic floor showing, but the insulation does not have to be removed. Yes, you probably need more insulation added (air seal the attic floor first) but even old insulation still has it’s R-value, or insulative properties. Unless it’s water damaged or rodent infested, you do not need to remove your attic insulation. Remember, if you are concerned about dust and air quality, you need to have your attic air sealed to separate the attic from the house before you add more insulation, otherwise you’ll just make the dust problem worse.
When Your Energy Audit Company Tells You They Need To Remove All The Fiberglass Batt Insulation Because It Is Misaligned
Of the few insulation companies that actually know what the problem is with “misaligned insulation,” I would wager that most are energy auditing companies. You can see photos of what misaligned insulation looks like and read up on why it’s like having half your insulation gone here. And of those energy auditing companies, there are some that are lazier than others and would recommend you remove all the fiberglass batt insulation in the attic to fix the misalignment problem. The problem with this approach is that it will cost you twice as much as add a day to your job and is not needed. You’ll be charged an extraction fee to remove the insulation, which takes at least one day. Then you’ll have to pay to have your entire attic reinsulated, which will take another day.
YOU DO NOT NEED TO REMOVE YOUR FIBERGLASS BATT INSULATION. It still has its insulative properties and just needs to be installed properly to work right. What I recommend to our customers is a process called lift and fill. This method is doesn’t require more man power, but does require more skill which is why I perform all our lift and fill jobs myself or someone I’ve trained and worked with for over a year. Lift and fill requires the installer lift and blow loose fill insulation under each fiberglass batt, then replace the batt and blow loose fill insulation on top, creating a sandwich of fiberglass batt insulation. The loose fill insulation is able to form around canned lights, under electrical wires and cross studs and in-between stud cavities. If done properly, the difference in comfort is night and day and we don’t need to charge double to properly insulate your attic.
HOW IS THE INSULATION REMOVED FROM THE ATTIC?
For loose fill or blown in insulation we use an extraction machine to suck out the insulation. We use the same machine to suck out the insulation when we are applying spray foam along the roof decking. Many homeowners have tried to remove the insulation by hand in trash bags but anything over 500 sq ft is a monumental task and has always proven too much work. The extraction will suck out the insulation from a 6” hose and fill 20 gallon bags. A typically 2000 sq ft home will use about 6-10 extraction bags. For fiberglass batt removal, it must be done manually, one batt at a time.
HOW MUCH DOES INSULATION REMOVAL COST?
Insulation removal cost will depend on the existing depth of insulation, square footage, attic access and offshoots, and if it is rodent infested. The cost will range from $0.70-$1.50 sq ft for extraction.
WILL REMOVING MY INSULATION MAKE MY AIR QUALITY BETTER?
If your home has lots of air leakage and connections from the attic into the house, then yes, but the attic floor must be air sealed after the insulation is removed or spray foam applied to the roof decking. Simply removing the insulation, then blowing new insulation is not guaranteed to improve the air quality because all the leakage pathways from the attic into the house will still be present. Once all the insulation is removed, the attic floor needs to be air sealed to stop the transfer of attic air from going into the house. I also recommend having each room pressure balanced and ductwork sealed. Room pressure balancing is important if you notice doors close by themselves when the air or heat comes on, or you notice a rush of air under the door with the HVAC system running. Not fixing a room pressure imbalance can cause outside air to come in the home from the outdoors or the attic because that room becomes pressurized while the rest of the house gets put under a negative pressure and sucks air in from the outside.
Having spray foam applied to the roof deck creates a sealed attic space with no ventilation. This creates an air tight attic where the insulation cannot collect dust from the outside and it cannot enter the home. Spray foam does off-gas for about 6 hours after it’s applied but once it’s cured there is no ongoing off-gassing. In Phoenix, our attics are vented to the outside so many layers of dust can accumulate in the insulation, especially fiberglass insulation. That dust can then find its ways into your home through air and duct leakage pathways. Attic insulation dust is a carcinogen and harmful to breath.
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