MaxxMinutes Blog

Installation of Resilient Flooring Over a Gypsum Underlayment

When installing resilient floor goods, such as vinyl plank, sheet vinyl and VCT, over thick poured gypsum concrete underlayments, it is important to follow proper installation procedures. Doing so ensures that the thick poured gypsum concrete underlayment is an acceptable surface to receive resilient floor goods. The American Society for Testing and Materials (ASTM) recommends specific guidelines in ASTM F2419 “Standard Practice for Installation of Thick Poured Gypsum Concrete Underlayments and Preparation of the Surface to Receive Resilient Flooring.”
Some of the key components of ASTM F2419 include:

  • Deflection
  • Building conditions
  • Gypsum underlayment minimum thicknesses and compressive strengths
  • Moisture testing
  • Final surface preparation

ASTM F2419 states that the subfloor must support design loads with a maximum deflection of L360. The building should be enclosed before the underlayment is installed and continuous ventilation is required while the underlayment is drying. The practice recommends that gypsum underlayments be installed at a minimum of ½” (13 mm) over concrete subfloors or ¾” (19 mm) over wood subfloors. When tested for compressive strength, in accordance with Test Method C 472, the underlayment should have a minimum of 2,000 psi (13.88 MPa) for use over wood subfloor and 3,000 psi (20.7 MPa) for use over concrete subfloors.

Prior to installation of the finished resilient flooring, moisture testing must be performed and the suitability determined by the finished floor goods manufacturer. Final surface preparation of the gypsum concrete shall be in accordance with the recommendations of the finished floor goods manufacturer. The thick poured gypsum concrete underlayment shall be primed prior to the installation of resilient floor covering as per the guidelines of the resilient floor goods manufacturer. If you have additional questions about installation of resilient flooring over a gypsum underlayment, we encourage you to contact your Maxxon Regional Representative at (800) 356-7887 or