Home Improvement Expert Danny Lipford

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Which Way to Face Insulation?

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Danny Lipford installing fiberglass insulation under floor.

On your show you said that when insulating under a floor, the paper facing should face up against the flooring. Why can’t I install it the other way? Does it make that much of a difference? -Kim

Hi Kim,
Regardless of whether fiberglass insulation is installed in a wall, attic, or crawlspace; the paper facing should always face toward the inside of the home. That’s because the paper contains a layer of asphalt adhesive which prevents water vapor from passing through it.

If the insulation is installed with the paper vapor barrier facing away from the heated part of the home, moisture from humid inside air can condense and become trapped in the insulation during cold winter months. This can lead to rot and mold.

For more about vapor barriers and insulation, check out our articles Vapor Barriers in Your Home and Attic and Basement Frequently Asked Questions.

Danny



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11 Comments on “Which Way to Face Insulation?”

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  1. michael Says:
    March 30th, 2010 at 3:30 pm

    just moved in my house…found out all the insulation faced is install the wrong way. will it hurt or i have change it

  2. Official Comment:

    Ben Erickson Says:
    March 31st, 2010 at 8:59 am

    Hi Michael,
    Depending on the climate where you live, it may or may not cause a condensation problem. Colder climates, like you have in Pennsylvania, will have more chance of condensation problems than a warm climate. Assuming the insulation isn’t too much trouble to get to, I would turn it over so the paper facing is toward the ceiling, or peel the facing off all together. If it is a lot of trouble to change it, feel under it during the winter and see if it feels damp. If it does you definitely need to fix it to prevent rot or mold.

  3. Robert Says:
    April 23rd, 2012 at 2:31 pm

    I am remodeling a shower stall and going to re-tile, when I did the demo I noticed the insulation was faced insulation and the paper was facing the outside. The shower has two outside walls. I live in the Sacramento valley area which gets very hot and dry in the summer, doesn’t get to cold in winter, but foggy damp days in the 30’3 and 40′s. So I am not sure which way to install the new insulation. I have install new insulation becasue of a valve leak got the old stuff wet.

  4. chris Says:
    August 17th, 2012 at 5:13 am

    I need to install new insulation which way is the paper should face. I live in Illinois and it gets cold in the winter

  5. Robert Says:
    August 17th, 2012 at 10:51 am

    I sent an email to owens corning asking them which way to put the paper in my case, They told me the paper goes to the warm side of the wall in winter type weather. which would mean for me the paper faces the warmer inside

  6. Matthew Says:
    February 10th, 2013 at 3:20 am

    I had a guy come over from the electric company to tell me how to save on energy cost. Some of the insulation in the attic is the stuff that blows on and doesn’t have a paper side. He said since it was low I could roll out R-30 on it, which I did. I put the paper side facing toward the inside of the house. Is this going to cause condensation in the winter and rot the insulation under the paper/water vapor and therefore the wood? I live in Fort Worth TX.

  7. Official Comment:

    Ben Erickson Says:
    February 25th, 2013 at 3:06 pm

    Hi Matthew,
    You can lay rolls or batts of fiberglass insulation over existing blown in insulation, but you need to use unfaced insulation to prevent moisture from being trapped between the layers. Since you’ve already purchased and installed faced insulation, your best bet is to peel the paper facing off the insulation you installed.

  8. Brad Says:
    March 14th, 2013 at 1:22 pm

    I live in Louisiana close to New Orleans, should I put my fiberglass insulation with the paper side facing the outside of the house, or paper facing inside towards the room?

  9. Barb Wilzen Says:
    August 5th, 2013 at 6:59 pm

    Which way should the paper face on insulation when insulating an attic wall between an attached garage and the house?

  10. Official Comment:

    Ben Erickson Says:
    August 12th, 2013 at 11:04 am

    Hi Barb,
    Your question was answered in the first hour of our August 10th Today’s Homeowner radio show in the rapid fire section. You can listen to the show on our website at http://www.todayshomeowner.com/radio/2013/08/10/todays-homeowner-radio-show-for-august-10-2013/
    Thank you for your interest!

  11. will guyon Says:
    April 1st, 2014 at 11:20 am

    we have a camp which is off ground with a patio like under it. we insulated the floor of camp but birds and wasp have built in it. we would like to cover it with something any suggestions, we are thinking about psk insulation would that cause moisture to build up. i want the paper side facing down, and suggestion will be appreciated

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