Installation Guide

MOHAWK TECHNICAL SERVICES – HARD SURFACE | [e-mail] | 888.387.9881 1603_2020 | ES | 09/2020 | 4 of 12
Wood Suboors
Approved suboor panels should meet or exceed the following guidelines:
• Plywood must be minimum CDX grade (exposure 1) and conform to U.S. Voluntary Product Standard PS1 performance standard or Canadian performance
standard CAN/CSA 0325-0-92.
• Oriented strand board (OSB) must conform to U.S. Voluntary Product Standard PS2 or Canadian performance standard CAN/CSA 0325-0-92. The panels
must be tongue and groove and installed sealed side down.
• Particleboard must be a minimum 40-lb. density, stamped underlayment grade and 3/4" (19 mm) thick. (Floating installation only)
Floor joist/truss spacing will determine the minimum acceptable thickness of the suboor panels. Joist/truss spacing of 16" on center or less for single panel
subooring requires a minimum 5/8" (19/32", 15.1 mm) CDX (exposure 1) 4'x 8' suboor panels. Joist/truss spacing of greater than 16", up to 19."(488 mm) on
center, requires a minimum nominal 3⁄4" (23/32", 18.3 mm) tongue and groove CDX (exposure 1) plywood or OSB 4' x 8' suboor panels, glued and mechanically
fastened. Floor systems with joists/truss spaced greater than 19.2" (488mm) on center up to a maximum of 24" (610 mm) require minimum 7/8" tongue and
groove CDX (exposure 1) plywood or OSB 4'x 8' suboor panels, glued and mechanically fastened. Installation over joist spans greater than 24" on center is not
recommended. For installation over joist spans greater than 24" on center, consult NWFA for panel thickness guidance.
Solid Wood Suboor — Direct Glue or Staple Down Applications
• Minimum 3/4" (19 mm) thick with a maximum width of 6" (15 cm) installed at a 45° angle to the oor joists.
• Group 1 dense softwood (pine, larch, Douglas r, etc.) No. 2 common, kiln dried with all board ends bearing on joists.
• For direct glue-down applications add 3/8" (9.5 mm) approved oor panel underlayment.
Existing Wood Flooring — Direct Glue or Staple Down Applications
• Existing engineered ooring must be well bonded/fastened. When gluing over existing wood ooring, the surface nish must be abraded or removed to
allow adequate adhesive bond.
• Existing solid hardwood ooring that exceeds 6" (15 mm) in width must be covered with 3/8" (9.5 mm) approved underlayment and fastened as required.
• Do not install over solid or engineered ooring attached directly to concrete.
Wood suboors should be well nailed or secured with screws. Nails should be ring shank and screws need to be counter sunk. The wood suboor must be
structurally sound, without loose boards, vinyl or tile. If suboor panels are single layer, less than 3⁄4" thick, add another single cross layer for strength and
stability, minimum 3/8".
Underlayment oor panels must be installed sealed side down. When used as a suboor, allow 1/8" (3 mm) expansion space between each panel. If spacing
is inadequate, cut in with a circular saw. Do not cut an expansion space on tongue and groove panels. When installing parallel to the oor joists, it may be
necessary to increase rigidity of the structural suboor system by installing an additional minimum of 3/8" (9.5 mm) approved underlayment oor panel.
NOTE: Avoid suboors with excessive vertical movement or deection. If the suboor exhibits excessive vertical movement (deection) before installation of the
ooring, it will likely do so after installation of the ooring is complete. Indications of excessive deection are uneven nish wear, fastener release, squeaking,
compromised or damaged locking systems, sectional contours such as bowing or dipping in oors and uneven ooring material.
Radiant Heat Suboors
Mohawk engineered ooring can be used in combination with many types of in-oor heating. The heating system can be cast in a concrete oor or in a thin layer
of ller on the surface of a concrete suboor. It can also be installed under a wood suboor or installed on the surface of the suboor as an electrical matting,
provided it meets the oor atness requirements.
• Follow the instructions from the supplier of the oor heating system.
• Concrete suboors must be installed and cured with no heat transfer for a minimum of 60 days.
• The heating system must be in operation for at least two weeks before ooring installation.
• Prior to ooring installation, the system should be set to a suitable installation temperature (65° to 72°F).
• Following installation, temperature should be raised 2°F daily until desired temperature is reached.
• The ooring surface temperature, which is the surface of the suboor or the heat radiating from electric heating mats, should not exceed 84°F (29°C).
• Do not use area rugs on top of engineered ooring installed over radiant heat systems. Area rugs trap heat, creating elevated temperatures capable of
damaging engineered ooring.