Moisture barriers are designed to reduce the transmission rate of humidity from the subfloor to the flooring. There are various moisture barrier products, but the two main categories are roll-on and overlay. Both roll-on and overlay moisture barriers work well and mitigate moisture effectively. The type of moisture barrier you use depends on the circumstances and project type.
Overlay Flooring Moisture Barriers
Overlay moisture barriers are materials you roll out and install under the flooring. These moisture barriers can be made of paper, tar, or plastic. Overlay moisture barriers can be used on various subfloors, including OSB, particle board, plywood, and concrete. Overlay flooring moisture barriers are easy to use and spread out quickly.
Roll on Flooring Moisture Barriers
Roll-on moisture barriers are another common choice for moisture protection. Roll-on moisture barriers are made of a liquid or semi-liquid product rolled onto the subfloor. Roll-on flooring moisture barrier is commonly used over the concrete subfloors to keep moisture from wicking out of the concrete into the flooring. Liquid or roll-on moisture barriers come in two types; one-part and two-part products. One part moisture barrier can be rolled on without mixing with a catalyst or hardener. Two-part moisture barriers are mixed with a catalyst and then rolled on. The two-part roll-on moisture barriers are generally regarded as a better moisture protector, but waste can be an issue. When using a product with a hardener or catalyst any product left over will harden and become unusable.
Moisture Barrier FAQ’s
You would be able to use a liquid roll on moisture barrier. Liquid moisture barrier is able to be 100% moisture blocking and as little as 85%.
You would want to overlap the papers/palstics on each side to ensure slower transmission of humidity. For specific information go to the manufactuerers or architects page.
Each option does the job effectively. However, if you have RH of over 85% on the floor or a higher than nromal moisture reading it is ideal to use a moisture blocker that overs 85%+ or higher moisture contents. The liquid barriers are superior if you have a space with 85% or 10+ moisture.