Call our flooring experts:

(800) 220-7112

Search Site

Flooring Underlayment differences and do I need a moisture barrier?

 Every hardwood floor installed needs some form of underlayment, but not all flooring underlays are the same. Below we breakdown the different types of underlayment.

Felt Paper

 Felt paper, similar to roofing paper, is used when you are nailing your hardwood flooring down to a wooden sub-floor. The felt paper is used to help create a vapor barrier between the hardwood floor and the sub-floor. It will also help reduce the popping or creaks which can happen over time as the nails or staples can slightly lose hold. Simple Floors recommends and offers Aquabar felt paper for our products being installed using the nail or staple down installation method.

Moisture Barrier

 When you are installing a flooring using the floating installation method you want to make sure that the sub-floor does not contain more moisture than recommended by the hardwood flooring manufacturer. If you are having a professional install your new floors make sure they provide you with a moisture level reading before they start installing the floors. If the moisture level is too high you may still be able to install the floors, but you will need to lay down a moisture barrier. When installing over a concrete sub-floor it is always recommended to use some form of moisture barrier even if the moisture reading is below recommendations. The reason for this is because a concrete slab's moisture level changes based on its environment. At one time of year it may hold very little moisture, but later in the year it may have a moisture level higher then recommended.

 Moisture barriers can be bought as stand-alone products or can be integrated into other types of underlayment. A stand-alone moisture barrier is usually a 6 mil or 8 mil vapor barrier. These types of moisture barriers are laid down across all of the sub-floor prior to a floating floor installation. Once they are laid down other underlay is often placed over top.

2-n-1 Underlay

 Another way to get a moisture barrier is purchase an underlay commonly known as a 2-n-1 underlay. This type of underlay contains a moisture barrier and some form of padding. The padding in a basic 2-n-1 is helpful in floating floor installations because it will help mask any minor imperfections in the sub-floor.

3-n-1 Underlay

 While a 2-n-1 underlay contains a moisture barrier and padding, a 3-n-1 also includes a layer of heat insulator/reflector. The heat insulator/reflector is usually made from a silver material.

Sound Barriers

 Sound barriers come in all shapes, sizes and decimal level ratings. When looking for a sound barrier the important thing to look for is the density of the material not necessarily the thickness.  When it comes to sound inhibiting underlay, thickness isn't as important as the density of the material. An easy way to check the density of sound barrier underlay for a floating floor is what we call the thumb test. The thumb test can be performed by simply pressing your thumb hard into the underlay while it is sitting on a firm surface. If the indentation of the thumb lingers for a long time that means the sound barrier is not very dense.  Conversely if you press your thumb in and the padding bounces directly back to its original shape the barrier is extremely dense.  The denser a sound barrier underlay is the less sound will travel through it when the floors are used. Of course there are more technical ways to find out how good a sound barrier is and that is by checking the Impact Insulation Class (IIC) rating and the Sound Transmission Class (STC) rating. The IIC rating rates the ability of the underlay to block impact sound while the STC rating checks the ability of barrier to reduce airborne sounds such as TVs, Radios and voices. These ratings will help you decide which sound barrier is good for your flooring installation. Many condominium and apartment buildings have specific IIC and STC ratings they require if you plan on installing new hardwood floors in a residence with people underneath your living space. Before you purchase and install hardwoods in these types of spaces you will want to check with your association or management team to make sure the sound barrier you purchase meets their specifications.

Back to top