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When will I need to use a moisture barrier when installing laminate flooring?

All laminate flooring requires an underlayment to allow the floor to float and give the locking system its strength. Sometimes the underlayment is already attached for you, but you may hear the term moisture or vapor barrier when installing laminate flooring. You may be wondering if you will need to use a moisture barrier. Depending on your subfloor and project, you will need a specific type of underlayment.

You will need a moisture barrier underlayment when installing:

  • On a cement subfloor
  • On any subfloor that has a chance of moisture coming up and soaking into the flooring

Moisture barrier underlayment acts as a blockade between the subfloor and laminate to protect your floor from any moisture damage. It really is as simple as it sounds!

Do I need to use a moisture barrier?

The Different Types of Moisture Barriers Explained

Some moisture barriers are very simple and some are part of the underlayment you would install anyway. Moisture barrier + underlayment makes installing over moisture prone subfloors super easy! Here are our favorite budget-friendly underlayments that can provide your moisture blocking needs:

  • Visqueen 6Mil PE Vapor Barrier: This is a thin, plastic underlayment not meant for padding, but only for blocking moisture. Perfect for under laminate flooring with pre-attached pad or luxury vinyl plank flooring, where you don’t need the extra padding.
  • Vapor Barrier 2-in-1 Underlayment: This 2-in-1 underlayment will allow your laminate flooring to float, while correcting any minor subfloor imperfections, and will protect your floors from moisture. Use Vapor Barrier 2-in-1 when installing laminate flooring on cement subfloors or any subfloors with a risk of moisture coming up.
  • Vapor 3-in-1 Moisture Underlayment: Vapor barrier 3-in-1 underlayment is perfect for installation under laminate flooring to allow your floor to float and give a moisture barrier. It also self-adhesive, which will make installation even quicker. You won’t have to fuss with tape or anything with this underlayment because it’s all right there for you. Vapor 3-in-1 Blue underlayment is the most budget friendly option of all vapor barrier underlayment.
  • Vapor 3-in-1 Underlayment Silver (100 sq.ft roll): This 3-in-1 underlayment can be used under any laminate flooring to allow your floor to float and create a moisture barrier. What makes this stand out from the 3-in-1 Blue underlayment is the added noise barrier to reduce foot fall noise. If you need a quiet floor with moisture blocking properties, this is a great option!

Which Underlayment should I use?If you’re looking for premium underlayments, we have those too! These are the three best premium, moisture blocking underlayments we carry at Bestlaminate:

  • Floor Muffler Underlayment: Floor Muffler padding underlayment has the highest and most effective sound barrier for floating floors, along with superior moisture blocking technology. This underlayment is not only strong and flexible but is light as well making it easier for the installer to take up and down wherever it is needed.
  • Felt Premium Underlayment: Felt padding underlaymnet provides a vapor barrier, insulation, and sound reducing properties. This 3mm will reduce noise while keeping the moisture out, giving you more bang for your buck.
  • Robert’s Silent 3-in-1 Vapor Underlayment (100 sq.ft. roll): If you’re looking for sound reduction more than insulation, this underlayment is perfect for you. The small white foam balls in the underlayment help with air circulation so your floor is mold and mildew free. When walking on your floor the air begins to circulate around all the foam balls, absorbing sound!
  • Kronoswiss Provent Silent Vapor 3-in-1 Underlayment (215 sq.ft. roll): This multifunctional underlayment from Kronoswiss provides heavy duty sound insulation underlayment. Kronoswiss ProVent not only effectively minimizes the noise level when walked on, but also the sound level transmitted through the floor into adjacent rooms. Unique Micropumping System supports air circulation. ProVent underlay is shaped to allow the formation of a system of air channels which ensures a constant exchange of air when walked on and also eliminates water vapor from the floor.

No matter which underlayment you choose, if you are installing on a moisture prone subfloor or concrete subfloor, you really need a moisture barrier underlayment. Protect your laminate flooring from moisture for years to come by installing moisture barrier underlayment.

If you still have questions, don’t hesitate to post them in the comments below or give us a call at 1-800-520-0961! We will be happy to help you!

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*This post was updated from 2014 to give you a better reading experience!

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18 comments

  1. Avatar

    Hi, I am installing laminate flooring that has 2mm attached foam backer and the floor is plywood on crawlspace. Should I use moisture barrier?

  2. Avatar

    Your diagram shows if you already have an underlayment you don’t need a moisture barrier if installing over hardwood, which I’m doing. On the other side of the diagram it says if you don’t have the underlayment to install that and then you can use vapor 3in1. Doesn’t vapor 3 in 1 have a vapor barrier? Then why would you use that, why not just the underlayment like it mentions on the left side of the diagram? I’m trying to figure this out because I have a terrible musty smelling crawl space that seeps up into the rooms and was thinking of putting a moisture barrier under my cortec cork underlayment floor i bought going over existing hardwood. Would that cause a problem? Thanks.

    • Alana Kane

      Hi Paul, thanks for the question. Since your COREtec already has underlayment attached, you could just a moisture barrier film. You should not use additional cushion. My biggest concern is: Has the moisture/smell affected your hardwoods at all? I would recommend looking into ways of eliminating the moisture and smell from the crawl space vs trying to just cover it up. If your hardwood starts to be affected (buckling or swelling at the joints), it will only cause more issues for the floor you’re laying above it.

  3. Avatar

    Which order do you use. visqueen first then subfloor then laminate or subfloor then visqueen then laminate?

    • Alana Kane

      Hi RonRea, it will be subfloor, visqueen, cushion underlayment and then the laminate flooring. If you have any other questions about this, let us know!

      • Avatar

        I’m confused here: *In the first part of the article is explained when we need and when we don’t a moisture barrier…(table)

        In the second part:
        *”No matter which underlayment you choose, if you are installing on a moisture prone subfloor or concrete subfloor, you really need a moisture barrier underlayment.”

        I have laminate in basement, installed on tails, with ” airflow foam” but turned wrong way from previous owner. So i don’t know if was only that reason of moisture or i need something different like:
        * 2in1 vapor barrier
        *floor muffler
        * or combination of vapor barrier and airflow foam..?
        If you can give me an advise i would appreciate that. Thanks
        *

        • Alana Kane

          Hi Milan, sorry you were confused by the article! I will take a look and edit to make more sense. With your concrete subfloor, you will need either a standard foam underlayment with a moisture barrier film, or a 2in1 underlayment with moisture barrier already installed. Usually, buying the 2in1 is an easy and more economical option! You can check out our underlayment options here: https://www.bestlaminate.com/accessories/

  4. Avatar
    Angelo Melchiorre

    My laminate flooring (Pergo Outlast+) already has underlayment attached to it. I’ll be installing in my basement which is above grade and has concrete sub floor. Is a vapor barrier overkill here?

    • Alana Kane

      Hi Angelo, thanks for your question! I’d recommend looking at what Pergo recommends for concrete subfloors. In general, we always recommend a moisture barrier or an underlayment with built in underlayment for concrete subfloors.

  5. Avatar

    Looking to install laminate or engineered wood over the current flooring in a pier and beam house. One room has linoleum already installed, all the others have hardwoods. First question is can the engineered or laminate be installed over the top of the linoleum? Second question is do I need to put a moisture barrier under the current flooring before installing the laminate/engineered woods?

    • Tyler

      Hey Marty, a floating floor can be installed over linoleum or hardwood as long as it is glued down. Then the floating floor can go over top. YOu would just need a basic foam padding to go over these floors.

  6. Avatar

    Should a tape be used to seal the overlap between sheets of vapor barrier and what type or brand of tape is best?

    • Alana Kane

      Hi Tom, it is recommended to tap the overlap. Masking tape or packaging tape will work well. Best of luck on your install!

  7. Avatar

    I purchased laminate with an underlayment but I would like to still out a vapor barrier underlayment, for more warmth and less sound. Would that work ok, or will I have future problems? It is in a mobile home.

    • Avatar

      Hi Judy, thanks for your comment. The pre-attached underlayment on your laminate will provide basic cushioning and sound dampening. Additionally, you can go ahead and install a vapor barrier such as Viqueen to add moisture protection. We do not recommend installing an extra layer of underlayment (except Visqueen) under your flooring. This would create too much cushioning beneath your floor and could impact the joint integrity. Please let us know if you have any other questions!

  8. Avatar

    If the subfloor has a moisture barrier put down before the subfloor is installed do you still need a moisture barrier put down before you in stall laminate flooring?

    • Avatar

      Hi Tim – Good question! We would still recommend using a moisture barrier on top of your subfloor to protect your laminate flooring. Please feel free to call us at 1-800-520-0961 if you have any more questions or you can browse our Help Pages for more installation related questions!

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