Floor Muffler™ underlayment is an excellent product that can be used in any floating floor installation. The product works equally as well over concrete and plywood below or above grade sub-floors. Finished flooring materials can be any thickness of laminate including laminates that have a cork finish layer as well as engineered hardwood and bamboo flooring products.
Figure 5 - Modified underlayment
Modified and/or Upgraded Underlayment:
There are a vast variety of modified and/or upgraded underlayment. The primary difference between these and the standard foam underlayment is that they are generally more dense and/or have more depth. The basic materials used are:
- Rubber
- Fiber
- High-density Foam
- Closed-cell Foam
Using these materials the manufactures attempt to instill a better level of sound attenuation then is found in standard foam underlayment. There is little improvement, if any, in these underlayment materials as far as their abilities to smooth out any sub-floor irregularities or walking comfort, compared to standard foam or standard foam and moisture barrier combined underlayment. These modified or upgraded underlayment, as they are termed, are very expensive and overall there improvement is sound attenuation does not compare to that of cork underlayment.
There are many types of modified or upgraded underlayment and unlike standard foam or a standard foam with an integral moisture barrier the products differ dramatically from one another, depending on the manufacturer. Some materials will be thicker, some more dense and the specifications for sound attenuation, comfort level and life will vary dramatically between manufacturers. As well, an integral moisture barrier is not part of all the products.
Because of its improved sound attenuation characteristics modified or upgraded underlayment are commonly used in high-rise applications, even though their sound attenuation characteristics are less than cork. As stated these products do not provide additional comfort.
Cork Underlayment:
If Floor Muffler™ underlayment is the Cadillac of underlayment, then cork underlayment (Figure 6) is definitely the Ferrari. The benefits of cork as an underlayment are many:
- Unlike foams and rubbers, cork is porous and breaths, hence it will not hold moisture.
- It is a renewable resource. Cork is the bark of the cork tree, a species of oak. Once the cork or bark is harvested the tree will grow another layer. Additional information on cork.
- The best sound attenuation of any underlayment product.
- Available in different thicknesses which offers different sound attenuation levels (see Note).
- Provides the best comfort and walking feel. Comes the closest in making laminate and engineered hardwood flooring feel like and sound like natural hardwood flooring.
- Increases height of the sub-floor to match ceramic tile and other higher profile flooring materials.
- Cork underlayment is sold in rolls, making it very easy to install. In many cases standard foam underlayment will rip or tear as you are installing the finished flooring. This can make installation of the laminate or engineered hardwood flooring very frustrating.
Figure 6 - Cork underlayment
Note: Although cork underlayment is available in many thicknesses, 6mm (7/16 inch) is considered to be the optimum thickness. Any thicker than 6mm and the cork underlayment does not offer any noticeable sound attenuation improvement. It should also be noted that some manufacturers will void warranties on floating laminate or engineered hardwood flooring installed on cork underlayment that is thicker than 6mm.
Cork laminate does not come with an integral moisture barrier, so if a moisture barrier is required it will be necessary to install a 6 mil plastic under the cork underlayment. Make sure you verify the manufacturers warranty and installation instructions of their finished flooring.
Cork underlayment does not have to be glued or stapled down if it is used under a floating laminate or engineered hardwood flooring material. Although it is common to tack down the edges in order to stop the rolled material from rolling back-up as you are installing the finished flooring.
Condominiums & Multi-Occupant Buildings:
If you live in a condominium, co-op or other multi-occupant building, their may be rules and regulations regarding the installation of flooring materials and especially the types of underlayment that can and cannot be used. In many cases cork is specified as the only acceptable underlayment because of its sound attenuation qualities.
It is critical that if you live in a condominium, co-op or other multi-occupant building that you verify what if any rules exist that pertain to flooring before you purchase any underlayment, laminate, hardwood or engineered hardwood flooring. Not to do so could place you in the very expensive situation of having to remove whatever underlayment and flooring you have just installed.
Special Consideration:
A common mistake made by many homeowners, when installing laminate, engineered hardwood or natural hardwood is to skimp on the the sub-floor preparation, which includes the underlayment. As with many other home improvement projects, what you don't see can be as important, if not more important than what you do see. To spend a lot of money on a finished flooring material and not install it properly is truly a waste of money. Making sure the sub-floor is level and has few imperfections, choosing the correct underlayment when dealing with laminate and engineered hardwood flooring is critical to the successful completion of the project.