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Supress installs easily in standard floor assemblies both in renovation/remodels and in new construction.

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Supress Sound-Engineered Plywood (SEP & SEP-AM)

Supress SEP are engineered soundproofing wood products and engineered structural wood products that provide exceptional sound isolation (STC 61-70), impact noise (IIC 51-74) and vibration absorption in standard 4' x 8' panel sizes.

In new construction, Supress SEP can be used in place of regular plywood, OSB, underlayment and subfloor or for upgrades to existing structures. Supress SEP can be applied directly over existing wood flooring surfaces to gain additional strength and acoustical performance in standard floor/ceiling assemblies.

Supress SEP subflooring is span-rated and designed to replace standard subflooring in single-layer or multi-layer (subfloor-underlayment) floor/ceiling assemblies utilizing either wood or metal joists. Each panel of Supress Subfloor is grade-stamped PS 1 Exposure 1.  Exposure 1 panels are suitable for uses not permanently exposed to weather. Supress subfloor products have square-cut ends and tapered tongue and grooves on the long edges.

Builders can create simple floor/ceiling assemblies with STC 61 and IIC 51 performance using Supress Sound-Engineered Plywood (SEP) and Supress Sound-Engineered Drywall (SED).   Remodeling an exisiting floor/ceiling assembly? Apply Supress 5/8" SEP Underlayment over your existing subfloor to deliver superb acoustic performance.
  • Next-generation, high-performance sound and vibration absorption in thin panel construction (5/8", 3/4", or 1 1/8" thick)
  • Safe, non-metallic construction: Does not interfere with cellular reception, wireless network, SmartHome, or Home Theater wireless (RF) operation and equipment links
  • Low labor cost: Cut with standard saws and install as regular plywood-No special tools or equipment required for installation
  • Water-based materials for interior use
  • Shear Panels and Subflooring are grade-stamped PS-1 Exposure 1 rated
  • Subflooring is 24" Span-rated
  • Fire-rated
  • Lab and field performance-tested
  • Supress SEP products are available with non-toxic, biodegradeable, anti-mold properties (SEP-AM)


Solve noise problems with hard-surface floor coverings such as hard and soft woods, marble, stone or vinyl tile easily with Supress Sound-Engineered Plywood and Supress Sound-Engineered Drywall.   Create super-quiet assemblies with carpet and pad over Supress Sound-Engineered Plywood. Supress SEP contains no metal and has true Tapered Tongue & Groove construction--unlike other solutions--eliminating installation and usage headaches.

Planning/Design for Your Project

For the best soundproofing results in your project, please consider the following:

Air and structure-borne sound are very aggressive in nature and tend to spread out through a building's structure. For example, to suppress the unwanted sound you perceive as coming through a floor/ceiling assembly, you may need to extend your coverage to the adjacent walls and ceilings including soffits or other architectural elements.

Wall, floor and ceiling penetrations create paths for sound. Make sure that any openings for recessed lighting, audio speakers, electrical outlets, fire sprinklers, etc. are fully sealed, otherwise sound energy may pass through these areas, reducing overall acoustic performance. Doors and windows also create paths for unwanted sound. Remediate or specify the appropriate assembly for the performance desired. Please discuss the details of your specific application with a Supress representative.

How to Order Supress Sound-Engineered Plywood in 4' x 8' panels:

Supress Sound-Engineered Plywood in 4' x 8' panels  Product Application

  • 5/8" SEPS5848 Shear Wall
  • 5/8" SEP5848 Floor Underlayment/Upgrade/Remodel
  • 3/4" SEP3448* Subfloor-New Construction
  • 1 1/8" SEP11848* Subfloor-New Luxury/Commercial Construction
  • Square edge unless otherwise noted. Anti-mold versions available (SEP-AM). Available in 12' lengths special order for production builders.
    *Available with Tapered Tongue and Groove edge.

How to Install Supress Sound-Engineered Plywood Subfloor

Prepare Surface and Materials
The joist and cross-member edges must be reasonably clean and dry. Remove nails, screws or any obstructions which are covering or protruding from the joist and cross-member line.
Protect smooth panel faces and tongue and groove edges from damage prior to and during installation. To minimize the potential for panel buckling and/or nail-pop, allow Supress SEP panels to equalize their moisture content at the job site by allowing air circulation on all sides for a few days after delivery.

Measure and Cut
Measure the space and, if needed, cut the panel (with standard or carbide-tipped saw blades) to the proper size, minimizing the gaps between panels and with other surfaces.

Glue and Attach
Glue-nailing is recommended for Supress SEP panels. Use adhesive conforming to ASTM D3498 and spread only enough adhesive in a 1/4" bead on framing members to lay 1 or 2 panels at a time. This is particularly important in warm weather conditions where the adhesive will dry more quickly. Panels may also be nailed only with appropriately-sized cement-coated ring- or screw-shank nails. Specifications to be provided by project structural engineer.

Glued tongue and grooved edges are recommended under thin floor coverings to keep joints snug. Glue by spreading a thin line of adhesive (1/8" bead) into the open groove. Avoid using too much adhesive as this will create squeeze-out and require additional labor for clean-up.

Use 8d cement-coated ring- or screw-shank nails at a maximum spacing of 6" at supported panel edges and at a maximum spacing of 12" at intermediate supports.

Attach panels GRADE STAMP UP, away from joist faces and perpendicular across framing members continuously for at least 2 spans. Stagger the end joints of the panels across framing members.

Seal Cut-outs and Penetrations
Due to the aggressive nature of air- and structure-borne sound, Supress recommends that any cut-outs or penetrations in the flooring system for mechanical, HVAC, pipes, wiring, fire sprinkler nozzles, etc. be completely sealed with Supress Acoustical Sealant.


Additional Supress Sound-Engineered Products:

  • Supress Sound-Engineered Drywall
  • Supress Acoustical Sealant
  • Supress Sound-Engineered Channel


Supress Sound-Engineered Products are available through local professional building supply dealers and distributors throughout the US, Canada and Mexico.

Copyright © 2005-2008 Supress Products, LLC. All rights reserved. Supress and the Supress logo are Registered Trademarks ® of Supress Products, LLC. Sound-Engineered, Sound-Engineered Drywall, Sound-Engineered Plywood are Trademarks™ of Supress Products, LLC.