Substrate Preparation
By Tim Fahey
Surface Specialist LLC
Prior to the application of any type of flooring system, the surface upon which it is to be applied, the substrate, must be evaluated. A substrate is the “foundation” of the entire flooring system and therefore can ultimately determine its short and long-term success. The first condition an INSTALL contractor will evaluate before flooring installation is the condition of the substrate. When a professional evaluates the substrate the following conditions are considered:
- Cracking and/or structural movement
- Spalling and/or loose, poorly bonded materials
- Flatness tolerances
- Levelness tolerances
- Surface contaminants which may interfere with the proper bonding of adhesives
- Compressive strength
- Smoothness
- Structural integrity
- Moisture intrusion and/or future exposure to moisture
- Ph/alkalinity — adhesive compatibility
- Dusting/delamination
- Protrusions & penetrations
The proper evaluation of the substrate must consider specific requirements of the flooring finishes. An INSTALL contractor will “match” substrate preparation requirements with the new flooring material. Typically some form of preparation is needed and the following is a range of preparation options available:
- Skim coat or flash-patch minor imperfections
- Sanding of rough spots/areas
- Grinding of “high spots”
- Manual or mechanical removal of contaminants such as old mastics, adhesives, glues, etc.
- Leveling or flattening of the surface utilizing special polymer-modified cements, such as Drytek, ARDEX, or USG Levelrock.
- Moisture evaluation and various remediation methods, including vapor barriers or Drytek underlayments.
- Sealing of penetration and removal of above-floor protrusions.
- Sweeping, cleaning, and vacuuming
The methods and materials used to correct substrate deficiencies vary widely. “Resilient” flooring requires the greatest degree of substrate preparation because it is not a thick material like carpet. Resilient flooring has substrate “flatness” tolerances that must be followed. In order for this type of flooring to be installed correctly, the substrate must achieve a flatness of at least ¼" to 1/8" elevation deviation over any given 10' radius span. Unfortunately most unprepared substrates do not achieve this standard of flatness and require one or a combination of preparation options noted above. Your INSTALL contractor is trained to identify and correct the deficiencies so that the new flooring performs to the best of its potential.