Subfloors and Underlayments - Resilient \ Wood or Board-Type Underlayments\Underlayments

Subject to the board manufacturer’s recommendations and warranties, the following underlayments may be used with Armstrong resilient flooring products with certain limitations indicated for each underlayment type.

*Some Lauan may present severe problems such as discoloration, indentation, loss of bond and delamination when used as an underlayment.

a) Plywood

  1. APA Trademarked Plywood or Equivalent Agency Certified Plywood rated as suitable underlayment for resilient floor coverings such as tile or sheet vinyl. It should have an Exterior or Exposure 1 exposure durability classification and a fully sanded face. APA plywood underlayment grades recommended for areas to be covered with resilient non-textile flooring are A-C, B-C, C-C Plugged or C-C Plugged EXT when marked “sanded face.” Also, Marine EXT or sanded plywood grades (A-C, B-C, A-D or B-D) marked “Plugged Crossbands Under Face,” “Plugged Crossbands (or Core),” “Plugged Inner Plies” or “Meets Underlayment Requirements.”
  2. Poplar or Birch Plywood with a fully sanded face and exterior glue.
  3. Lauan Plywood, when used as an underlayment, should be Type 1 (Exterior). The best grade is BB and the next best is CC, while OVL (overlay grade) is the minimum acceptable face grade. There is a wide variety of quality and species classed as lauan. Some may present severe problems such as discoloration, indentation, loss of bond and delamination when used as an underlayment.
  4. Treated Plywood- Armstrong resilient flooring is not recommended directly over fire-retardant treated plywood or preservative treated plywood. The materials used to treat the plywood may cause problems with adhesive bonding. An additional layer of at least 1/4" thick underlayment should be installed for the construction to still meet the applicable building or fire codes.

b) Hardboard
c) Oriented Strand Board (OSB)
d) Particleboard
e) Fiber Reinforced Gypsum Underlayment, Fiber Cement Board and Cementitious Backerboard
f) Wood Subfloors with Concrete or Gypsum Toppings


Regardless of the type of underlayment used under Armstrong resilient flooring, the responsibility for warranties and/or performance guarantees for the underlayment rests solely with the underlayment manufacturer and/or supplier and not with Armstrong.

The types of subfloors and underlayment panels described in this manual (F-5061) are intended only as a guide and should not be construed as an Armstrong warranty for these products.

Armstrong cannot be responsible for:

  • joint or texture show-through
  • tunneling and ridging over underlayment joints
  • discoloration from stain sources in the panel, regardless of the type of underlayment panel used
  • underlayment panel problems caused by local climate conditions, basement wall and subfloor construction or improper installation

    We strongly suggest that you secure a written guarantee and installation instructions from the supplier or manufacturer of the underlayment board being used.