Urethane vs. Acrylic adhesives

If you are about to install engineered hardwood using the glue down method, I recommend that you read this article. One of the most important factors when installing engineered hardwood is the adhesive. Using the proper adhesive is critical to a successful installation. In this article I will briefly cover the differences between Acrylic and Urethane based adhesives.

Let me start with acrylic adhesives. Acrylic adhesives are resin based and contain a certain percentage of water in them. The main problem with resin based adhesives, is the lack of tensile strength. In order for Acrylic adhesives to perform at their optimal level, the sub-floor needs to be well prepared and extremely flat. If the sub-floor is not level and flat and you choose to use an acrylic adhesive, I guarantee you will have hollow spots once the job is complete. Hollow spots are areas in which the wood floor is not adhered properly to the substrate. This problem is common and can be recognized by a popping or hollow sound as one walks across the floor. This is not an adhesion problem, but rather an installation problem. The main benefit to Acrylic adhesives is the trowel-ability and the clean-up factor. The other main benefit of acrylic adhesives is the cost. Acrylic adhesives and less expensive than its urethane counterpart.

Urethane adhesives are the preferred adhesives by most all major manufactures and should be used in most circumstances. These type of adhesives contain no water and have a much higher tensile strength than acrylics. When using a urethane adhesive it is very important to clean as you go. Urethane adhesives when left on a wood floor can cause permanent damage to the finish, making it difficult to repair. In essence Urethane adhesives are more difficult to clean, but do a better job of sticking the wood to the sub-floor. Depending on the type of urethane, there can be a significant cost difference in between them. Another downside to urethane adhesives, is that they are more difficult to spread than acrylic adhesives. Some installers will not use a urethane adhesive because, they are more difficult to spread and are harder to clean up. This is not an excuse for refusing to use them. If an installer comes into your home and wants to use an acrylic adhesive, it may be because he may be in a hurry. Remember, be very careful who you let in your home to do the work. It could cost you big time.
For additional technical info, please email me at cooperjm68@yahoo.com
Thanks,
The Floor Man