Preparing Your Attic for Additional Insulation - Prep Work
Preparing Your Attic for Additional Insulation
Before you buy the insulation and start hauling hoses or bundles up into your attic, do yourself a favor and do your prep work first. It's a lot harder to do with large bundles of insulation or a 3" hose everywhere you turn.
The prep work for adding insulation to your attic includes:
-Air Sealing
-Installing Attic Ventilation
-Isolating Heat Sources
-Bringing Electrical Up to Code
-Stocking Up on Supplies
-Preparing the Workspace
-Getting All Dressed Up
Air Sealing
The last thing you want to do is add insulation to your attic without air sealing first. Up to 30% of the your heating and air conditioning escapes through gaps, cracks, and holes in your walls and ceilings. Even if you have insulation properly installed.
Air sealing is the process of using caulk, expanding foam and other sealants to block the holes and cracks in your ceiling.
Trust me on this one, air sealing before you insulate is the way to go. It's a pain in the neck and a lot of work to remove mountains of insulation later on. Besides, you'll probably make your home more comfortable and save more money by air sealing alone, it's that important.
More on air sealing your attic...
Installing Attic Ventilation Baffles
Believe it or not, your attic needs to breathe. Otherwise heat and moisture can accumulate in your attic and cause wood rot and mold problems. To keep your attic and rafters healthy, you should staple styrofoam attic ventilation baffles underneath the eaves in your attic for proper ventilation. The baffles prevent insulation from blocking the air that circulates through your attic.
Your eaves are at the edges of your roof where the outside wall and the roof framing meet. To get back there, lay a long board along the outer edge of the attic floor. Crawl back into position with a couple of baffles and a staple gun handy.
Tuck the attic insulation baffle in between the roof framing making sure the outer edge of the vent is outside so air can flow through. Snap a couple of staples into each side of the nailing flange. Tuck a piece of fiberglass insulation between the attic ventilation baffle and the top plate. Then move on to the next one.
Isolating Heat Sources
Chances are you're going to have a couple of heat sources that need special attention. By heat sources, I mean chimneys, furnace flues and recessed lights protruding through the ceiling. Recessed lights and furnace flues get extremely hot. I've measured them at over 300 degrees.
Never install insulation next to or on top of these heat producing penetrations. Instead, air seal them with drywall boxes, sheet metal or some other fireproof material and high temperature caulk, then put fiberglass around them.
More on isolating heat sources in your attic...
Bringing Electrical Up to Code
Make sure that your electrical wiring is up to code. If you have exposed electrical wiring that is not tucked into a junction box or ceiling light box, it's time to get out your electrical tools.
If you have live knob and tube wiring, your project just got a lot more complicated because it could become a fire hazard. If you're not sure if you're up to code, it's probably best to call an electrician.
Stocking Up on Supplies

It may sound stupid to say but, "it's really hard to insulate without insulation."
I always buy more insulation, Great Stuff, caulk and attic ventilation baffles than I think I'll need. Not just because I hate driving to the store covered in insulation, but because I never have to get cheap or skip a few spots because I'm running out.
You can do a better job air sealing and insulating your attic when you feel free to use a little extra. And you can always take back leftovers to the store.
Preparing the Workspace
You're going to be working in your attic for hours at a time. So do yourself a favor make your work area safe by setting up some work lights and screwing down some boards or scraps of plywood on the framing in your attic so you don't accidentally fall into your living room. Don't laugh… my father-in-law did it twice.
Use plywood that's at least 1/2" thick and screw it down. You're going to rely on the boards to hold your entire body weight and stepping on the end of a loose board can be dangerous.
Getting All Dressed Up
I’ve learned to respect the itchiness of fiberglass insulation. So when I’m not working in 120 degrees, I like to wear long pants and shirts with a turtleneck if possible. Get a pair of nitrile coated work gloves for $3, a roll of duct tape and you’re good to go. Put the gloves on and wrap the duct tape around your wrists to keep small fiberglass particles from getting between your shirt and gloves. Slap on a funny hat, some goggles and a mask and get to it.
Buy a Good Mask
Breathing tiny little itchy particles into your lungs and throat causes all kinds of bad stuff to happen to you. Now I’m not a doctor, so I don’t know exactly what happens other than hacking and coughing, but it’s easily prevented just by investing in a good mask.
Cheap paper dust masks are worthless. The moment you start sweating or even breathing they start to get wet and make it difficult to breathe.
This 3M P100 respirator has a soft plastic base that makes an airtight seal over your mouth. The replaceable filters don’t clog with sweat and allow you to breathe safely for days.
Bottom line: If you invest in a good mask, you will use it more of the time and be safer for it.
Avoid Working in the Heat
Plan on insulating your attic in the fall or spring when it’s mild to cold out.
If you have to insulate in the wintertime it’s really not that bad but try not to insulate in the summer. I spent several days in 120-degree attics this July. Not only was I totally drenched in sweat, but the insulation coated every inch of my skin that wasn’t covered with clothing. It was a tough day and there was really no need for it.
Find a project in the basement or anywhere else in your home when it’s hot outside.