I am a first-time homeowner. One thing that was noted on the house inspection was that we needed more insulation for our attic. In my area, the recommended R-Value is 38 according to the ornl.gov site. Apparently 60 is "best" according to the JM.com site (link).

But how do I know what my current R-Value is?

  • Would help if you identified the type of insulation in your attic, and its thickness. Nov 6, 2011 at 0:13
  • @TheEvilGreebo - I'm a newbie, so I'm not quite sure, but it looks like this: certainteed.com/images/products/lowRes/…, and it's about 3 inches deep. It looks quite old, and also looks kinda ratty.
    – anon
    Nov 6, 2011 at 1:28

1 Answer 1


Ok that's fiberglass bat insulation, approximately R-3 per inch so a total of R-9. You can easily add more insulation on top of that - either buy more rolls of bat insulation (UNFACED - which means no paper layer on either side) - or you could blow in cellulose insulation (buy at Home Depot and get the blower rental for free.

Downside to cellulose is you need a body suit, respirator mask (not just a simple dust mask) and two people (one to feed the machine, one to blow it in the attic). Upside is it's 3.70 per inch so adding 15 inches would get you R-55, plus your existing R-9 is R-64.

Fiberglass bats, they're easier to install (roll em out, each layer criss crossing the previous) - but they usually come 3.5 inches thick - so you'll need to add 5 layers, which adds up pretty fast cost wise.

WELL worth it for the energy savings - but for a newbie, I'm gonna say spend more $ and get the bat insulation that's easier to roll out. And wear gloves, long sleeved clothing, and heavy socks and tape your pants to your socks and your shirt sleeves to your gloves...

Fiberglass itches.

  • You can buy thicker fiberglass bats, but the packages take 2 people to carry. I prefer the fiberglass because it's less likely to block the soffit vents and is easier to move when you need to make a repair.
    – BMitch
    Nov 6, 2011 at 2:07
  • 1
    And if all you can find is paper backed fiberglass, you can easily remove the paper.
    – BMitch
    Nov 6, 2011 at 2:08
  • I didn't use a bodysuit for blown-in cellulose. It probably would have helped, but a change of old work clothes did the trick. I would also add a headlamp to that list. You'll need one hand for balance and one hand for the hose. So unless you want to duct tape a flashlight to the hose, I'd get a headlamp if you're doing blown-in cellulose.
    – Doresoom
    Nov 6, 2011 at 17:36

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