DIY Projects

How to Install Fiberglass Insulation in Your Attic

By: Joe Truini

When installing fiberglass insulation in your home, be sure to put the paper or foil vapor barrier facing toward the heated and cooled living area of the home (down in attics, up under floors, in on walls) to prevent condensation from occurring.

If you are applying an additional layer of fiberglass insulation to your attic, use unfaced insulation on top of the existing insulation to keep from trapping moisture between the layers.


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20 Comments on “How to Install Fiberglass Insulation in Your Attic”

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  • Official Comment:

    Thomas Boni Says:
    January 26th, 2019 at 5:18 pm

    Hi, Barbara!

    We usually say adding insulation in the garage is not necessary to save energy dollars ( but your situation sounds different, based on the garage’s overhead space connecting with the attic.

    We recommend submitting questions involving unique situations like yours to the Today’s Homeowner Radio Show.
    Please use this form to contact Danny Lipford, America’s Home Expert, directly:
    Take care!

  • Barbara Says:
    January 26th, 2019 at 4:12 pm

    My attic space in the home that I recently moved into is completely open including over the garage space. I just noticed that there is no insulation over the garage. Should I add insulation over the garage? I was thinking if there was a wall in the attic separating it from the garage, it wouldn’t be necessary but since there is no wall, I should do it right? I have been finding conflicting information on this. Thank you for your suggestions!

  • ED Says:
    January 14th, 2018 at 2:59 pm

    Can i use an UNFACED insulation batt on a new attic?

  • gus Says:
    December 7th, 2017 at 5:13 am

    I have beach cottage 0n cape cod ma,, can I put insulation (attic ) in between roof rafters, to save on my heating bill, If so should the paper be facing the in side of the attic. or use craft paperless or (will I create a sweating /moisture problem??? $$$ can’t afford blow foam $$$

  • Dan Says:
    June 15th, 2017 at 11:25 pm

    Thanks for the video but I noticed your guy failed to mention what to do when there’s wiring in the rafter/joist bays where you’re installing the finerglass batts. To his left is knob and tube wiring running along the rafter and behind him is knob and tube running across. What to do? Install the insulation as he suggests regardless?

  • Official Comment:

    Lindsay Hughes Says:
    February 8th, 2017 at 3:14 pm

  • Walter Johnson Says:
    February 5th, 2017 at 4:59 am

    What kind of Insulation did you use in the a crawl space..How is the best way to do it.. I have concrete floors.. Thank you

  • Ron Boyd Says:
    October 27th, 2016 at 3:57 pm

    I only have four inches of insulation in my attic. I am going to put a four foot runway of boards down the middle of the attic so I have a way of getting around. If I add at least 8 inches more of roll or blown insulation how do I put insulation over the boards so I have access later to the attic?

  • Official Comment:

    Allen Lyle Says:
    August 18th, 2016 at 2:09 pm

    Rolled insulation is fine to use, just make sure you get “UNFACED” insulation. In other words, get the rolls that have no paper backing on them. I would also roll it out so it is perpendicular to the existing ceiling joists.

  • Angela Hill Says:
    August 17th, 2016 at 9:30 pm

    We currently have blown fiberglass insulation in our attic. We want to increase the insulation. Must we use more blown insulation, or can we add rolled insulation on top of what we have.

  • Stacie Says:
    June 23rd, 2016 at 10:20 pm

    What are your thoughts on the Attic Tent and how much does it really help at saving on heating and cooling cost? I live in Louisiana and purchasing a townhouse with attic stairs.

  • Adam Says:
    January 13th, 2015 at 11:21 am

    With a vapor barrier present won’t the moisture collect on the floor boards and create mold? House is in southeast pennsylvania. Summers in the 90s and winter in the teens

  • Official Comment:

    Ben Erickson Says:
    January 13th, 2015 at 7:55 am

    Hi Adam,
    When your attic doesn’t have any insulation, place the facing down toward the living space. In mild climates a vapor barrier isn’t necessary, while in colder climates it is to prevent condensation from forming in the insulation during the winter.

  • Adam Says:
    January 12th, 2015 at 5:08 pm

    My attic has no insulation. Completely floored. Do I use insulation with vapor barrier or in faced?

  • Official Comment:

    Joe T. Says:
    January 26th, 2012 at 8:42 am

    Hi Kate, It’s not necessary to insulate attic walls because it’s an unheated space. The idea is to keep the temperature inside the attic as close as possible to the outside air temperature. It makes much more sense–and cents–to insulate the attic floor, which in effective is insulating the ceiling of the rooms below. That way, you block heated air (and air-conditioned air) from escaping through the ceilings and leaking into the attic. Hope this helps. Good luck!–Joe T.

  • Kate Says:
    January 25th, 2012 at 5:32 pm

    Can you insulate the interior walls in an attic? I noticed in the above video that the walls are not insulated. My attic is the same.

  • Official Comment:

    Ben Erickson Says:
    October 31st, 2011 at 5:35 pm

    Hi Cheryl,
    The paper facing on insulation has an asphalt layer which acts as a vapor barrier. You only want one vapor barrier in your attic, and it should be as close to the ceiling as possible to prevent warm, moist air from coming up from the heated house and condensing when it hits the cold air in the attic. So if you’re installing insulation in an attic that doesn’t have any, used faced insulation and put the paper side down toward the ceiling. If you’re installing additional insulation in an attic that’s already insulated, use unfaced insulation that doesn’t have a vapor barrier. You can find out more in our articles on How to Apply a Vapor Barrier to Attic Insulation and Which Way to Face Insulation. Hope that helps!

  • Cheryl Gabriel Says:
    October 31st, 2011 at 2:33 pm

    This whole insulation installation is very, very confusing. The video above shows that the fluffy side of the insulation is facing up. When the recommendation is to put the fluffy side down with the paper part facing the ceiling. So why did this guy in the video have the paper side down towards the floor and the fluffy side up. Don’t forget we are homeowners who needs to understand in layman terms. Show us and tell us as if we have no common sense, because we don’t.

  • paul cope Says:
    October 8th, 2011 at 3:08 pm

    I just seal coated my driveway. I used a broom like bristle brush. It dried and you can see the streaks. From a distance it looks great. Question? Can I use a paint roller attached to a long handle and go over the driveway again to remove the brush streaking?? Will it work?
    Thanks. Paul

  • michael czmyr Says:
    December 23rd, 2009 at 7:12 pm

    i have 12″ of insulation in the attic, problem where a contractor put in the stove vent the snow has been melting, i added some insulation but this problem is still there, i could not get to the suffit area to put insulation on top of the pipe and i i did i would be blocking off any venting from there, actually the area they put the outside vent at that location is blocked, can i stuff that 1 section with insulation? i never noticed this until i moved upstairs in the garage and been like this for a long time.
    thanks mike

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How to Install Fiberglass Insulation in Your Attic