Home Improvement Expert Danny Lipford

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Which Way to Face Insulation?


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.


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17 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. 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

  11. joyce bagley Says:
    September 27th, 2014 at 12:58 pm

    I installed my insulation r30 under my cabin crawl space with paper side facing the ground, is this the wrong way? I live in north Ga. mtns near N.c line. Do u think its gonna be ok like I have it?please reply soon.

  12. Frank Says:
    October 7th, 2014 at 10:02 pm

    I bought an old mobile home. I updated the water lines to pex. I removed the skirting and went under and the insulation was non-existent. And what was there was thin and about 1″ thick. I plan to put r30 unfaced insulation under it and wrap it with the correct plastic. Also the mobile home has aluminum siding attached to 1/4th board nailed to the studs and the insulation in the walls was the same as under. About 1″ thick. I live in pa half hr 45 min north of Pittsburgh. There is a river about 1/32 of a mile away that keeps the area damp in the spring and fall. The area is usually colder then the weather station says.
    So to my questions.
    1.) Is it economical to put unfaced r30 insulation under the home. PS: I sealed all the holes and edges under the home with great stuff spray foam as a air barrier
    2.) What way do I face the paper in the walls? It gets to -5 sometimes in the winter and 98 in the summer.
    Addendum: Also I will be keeping the house at around 72-74 degrees in the winter months for my little kids. I will also be replacing the windows with double hung windows and having blown insulation in the roof/ceiling.

  13. betty Says:
    October 19th, 2014 at 12:00 pm

    I am trying to insulate the underpinned of a mobile home, I do not want to remove the metal skirting because is permanent, it will be hard to remove. So is it possible to use blue foam boards attached to the metal from outside. If is alright how should I do it in order to have ventilation and at the same time vapor barriers to avoid condensation issues ?
    Do I applied vapor barrier outside the metal then the blue foam boards, plus plaster or first the blue foam the vapor barrier and then the plaster or blue foam, plaster vapor barrier.
    the problem is that the ground has not vapor barrier, the belly is fine not holes, the underpinned is perfect too but seems cold in the winter. Going under the house is not an option for me or my children, the best solution is fixing the problem from outside.
    Any suggestions
    thanks in advance for your help

  14. mike Says:
    October 30th, 2014 at 7:57 am

    I have a metal storage building what would be the best insulation to use before I finish off the interior wall. right now I have nothing but 2x4on the wall to metal and the roof is 2×6 to metal

  15. Mike dugas Says:
    December 25th, 2014 at 7:39 am

    just purchased a home, the vapor barrier in attic is facing up, i am going to flip it over so it faces the ceiling. I want to add more batt insulation, am i correct in assuming that i should get the “Unfaced bat” and lay it over top of what is in the attic?
    thank you,

  16. Official Comment:

    Ben Erickson Says:
    December 25th, 2014 at 9:10 am

    Yes, you should put unfaced insulation (either rolls or batts) on top of existing insulation, so that you only have on vapor barrier facing the heated house.

  17. Dee Says:
    January 15th, 2015 at 8:12 pm

    We recently purchased a house with an addition that has an unfinished, as no heat, no electricity, in the basement of the addition. What would you recommend for insulation on the ceiling of the basement /floor of the upper portion of the room. We plan on eventually finishing the room. But would like to enjoy the space during winter months
    -If pink insulation vapor barrier closest to the floor or on the out side of insulation
    -foam insulation. Is it worth the cost?
    Thank you for your time

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