Insulating Your Home
Blowing Insulation into Your Attic
Blowing insulation into your attic is a fast and easy way to save money on your energy bills. Blowing insulation requires a special machine to break down the insulation into tiny pieces and blow it through a long hose. Both Lowe's and The Home Depot offer free rental machines with a minimum purchase of the insulation, usually about $250.
Blowing insulation is usually a 2-person job, one person puts the insulation into the machine and the other person holds the hose and directs the flow of insulation. You can do it by yourself by loading up the machine and running extension cords into the attic to turn the machine on and off. But I'd recommend convincing a buddy or your wife to help you out.
Preparing to Blow Insulation into your Attic
Before you buy the insulation and start hauling hoses 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 blowing insulation falls into 5 categories:
- Air sealing
- Installing ventilation chutes
- Isolating heat sources
- Bring electrical up to code
- Safety First
Air Sealing
The last thing you want to do is add insulation to your attic without air sealing first. Up to 30% of 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, mastic and other sealants to block the holes and cracks in your ceiling. Air sealing keeps the air you've paid to heat or cool inside your home and the air in the attic from getting in. 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.
Installing Ventilation Chutes
The next step in the project is to staple styrofoam vent chutes underneath the eaves in your attic for proper ventilation. 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 vents, some scraps of fiberglass insulation and a staple gun handy. Now put the vent 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. Wedge a piece of scrap fiberglass insulation into the space between the ceiling and the roof to prevent the wind from blowing your cellulose insulation around. Then move on to the next one. Fun, huh?
Isolating Heat Sources
Chances are you're going to have a couple of heat sources that shouldn't come into contact with cellulose. By heat sources, I mean chimneys, furnace flues and recessed lights protruding through the ceiling. Never install cellulose insulation next to or on top of these heat producing penetrations. Instead, air seal them with sheet metal or some other fireproof material and high temperature caulk. Then put fiberglass around them to prevent the cellulose from coming into contact with them. (Need video)
Bring 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. Or 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.
Safety First
You're going to be working in your attic for hours, so do yourself a favor and put some boards or scraps of plywood in the middle of 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. A couple of work lights can really help too. Make sure you have a good mask on. N-95 paper masks work, but I'd recommend a 3M 6291 half facepiece respirator. Paper masks just seem to get sweaty and restrict your breathing. And don't forget some way to communicate with the loader. Walkie talkies work great, but agreeing on 2 or 3 bags and then a break is always a good technique.
Gathering Supplies
Now, you're ready for the easy part. Blowing the insulation into the attic. When the day arrives, you'll need to get the insulation and the blowing equipment to your house. If you have a pickup and a trailer you should be able to make it in one trip. If not, you'll have to make several trips depending on the size of your vehicle. Just make sure to reserve the machine so you don't end up drinking beer with your buddy on a pile of insulation.
Don't Paint Yourself into a Corner
Try to work in an orderly fashion completing one section at a time. Work your way from the outside edges under the eaves then fill in the back walls. Pan back and forth with the hose as you work your way through the middle. Blow the insulation to the desired depth and keep moving. Pay attention to your footing! If the insulation starts to get away from you, don't worry. You can spread it around with a rake or broom later. Just don't go too far or you'll have to wade through the insulation without being able to see the ceiling joists.
Remove the plywood boards you were standing on as you move towards the attic hatch. The absolute goal is to get a nice even layer throughout the entire attic. You'll have to keep after the hose while your moving so it doesn't interfere with the places you've already insulated. Work you're way back to the center near the exit. You can stand on a ladder or attic stairs to finish off the job.
Insulation Dam
If you're raising the level of insulation in your attic, chances are the insulation is going to fall through the attic hatch. No worries, just make an insulation dam. To make the dam, measure the inside of your attic hatch and cut a couple pieces of scrap plywood to match. The pieces should stick up into your attic high enough to stop the insulation from falling down. Screw the cut pieces into the framing around your attic hatch and you're done.