Specifying a Subfloor

Now Comes the Hard Part...

Deciding what subfloor system to specify for your project! MFMA Mill Manufacturers have spent years testing and developing a host of subfloor systems to meet the needs of athletes and other facility users alike.

There are three basic subfloor designs: floating systems, fixed systems and anchored resilient systems. There are benefits and drawbacks to each basic design category depending on the unique parameters of your project.

• Floating systems are exactly what they sound like — they "float" over the concrete substrate, and are not mechanically fastened to the concrete slab in any way.

• Fixed systems are mechanically fastened by some method (anchor pins, screws, adhesive, etc.) directly to the concrete substrate.

• Anchored resilient systems are mechanically fastened to the concrete substrate, but have a combination of components that allow varying degrees of additional resiliency within the subfloor system.

Start your specification decisions by asking questions: Who will be using this floor? What activities will be performed on the surface? How often will the facility be used in an average year? Is the facility going to be subjected to long idle periods? What is the climate in the area of the installation? What types of HVAC systems can I specify for the space? Is the installation below-grade, on-grade, or above-grade? Answers to these and other questions will help you to eliminate subfloor designs that are inappropriate for your project.

Proprietary Anchored Resilient Subfloor System Designs

Multiple combinations of steel, wood, composite metal, plastic, neoprene, and rubber are signatures of most anchored resilient subfloor systems. Each MFMA Mill Manufacturer has created its own proprietary menus of combinations from which to choose. Depending on answers to the questions previously cited, your MFMA Mill Manufacturers may recommend one or more anchored resilient subfloor designs that will meet both the needs and design parameters of your project. Anchored resilient subfloor systems combine features of both floating and fixed systems.

Proprietary Fixed and Floating Subfloor System Designs

Each MFMA Mill Manufacturer also offers a variety of proprietary fixed and floating systems that they have developed in some cases for specific applications. Each one has unique features and benefits. Keep in mind that some of these subfloor systems have been designed for particular site conditions or expected uses (i.e. below-grade installation, installation in an area of widely varying humidities, use in an aerobics facility, use for modern dance stage, etc.).

"Generic" Anchored Resilient and Floating Subfloor System Designs

Most proprietary anchored resilient, fixed and floating subfloor system designs have evolved over the years from the designs of a number of "generic" MFMA subfloor systems. Each of these systems has been on the market for many years, and has been successfully installed in hundreds of facilities worldwide.

We refer to them as "generic" because the basic designs are not patented by one MFMA Mill Manufacturer, and each system is generally available from all MFMA Mill Manufacturer. The following is a short description of each of the "generic" MFMA subfloor designs.

Resilient Fixed Pre-Engineered Panel System

This system consists of resilient fixed pre-engineered panel system with MFMA Maple flooring stapled or nailed to the resilient subfloor. This system provides the stability of a traditional fixed system but with resilient properties similar to a floating system.

Resilient Fixed Plywood Sleeper with Continuous Subfloor System

This system consists of resilient fixed plywood sleepers with a continuous subfloor system with MFMA Maple flooring stapled or nailed to the resilient subfloor. This system provides the stability of a traditional fixed system but with resilient properties similar to a floating system.

Cushioned Sleeper System

The cushioned sleeper floating-floor system consists of 2" x 3" x 4' (nominal) kiln-dried hemlock, spruce, pine or fir sleepers installed over 3/8" x 2 1/4" x 3" or 5/8" x 2 1/4" x 3" resilient pads supplied by the flooring manufacturer. The pads are mechanically fastened to the bottom of the sleepers and are generally spaced at one-foot intervals on the sleepers. The sleepers with pads are installed end-to-end at right angles to the direction of the finished maple surface with end joints staggered 24" in adjacent rows. Sleepers are spaced between 8" and 16" O.C. depending on the thickness and grade of the maple flooring surface and the resiliency required for the project. The surface maple, sleepers and pads are installed over a seam-sealed 6 mil polyethylene vapor retarder.

Cushioned Sleeper with One Layer of Plywood System

The cushioned sleeper with plywood floating floor system consists of 2" x 3" x 4' (nominal) kiln-dried hemlock, spruce, pine or fir sleepers installed over resilient pads supplied by the flooring manufacturer. The pads are mechanically fastened to the bottom of the sleepers and are generally spaced at one-foot intervals on the sleepers. The sleepers with pads are installed end-to-end at right angles to the direction of the finished maple surface with end joints staggered 24" in adjacent rows. Sleepers are spaced 12" O.C., and a layer of 15/32" x 4' x 8' APA rated, 4-ply, APA (or flooring manufacturer's approved rated equivalent) Rated Sheathing is installed over the sleepers at either a 45 or 90 degree angle to the direction of the finished maple surface. The surface maple, sheathing, sleepers and pads are installed over a seam-sealed 6 mil polyethylene vapor retarder.

Double Plywood System

This low profile floating floor system consists of two layers of 15/32" x 4' x 8', minimum 4 ply, APA (or flooring manufacturers approved rated equivalent) Rated Sheathing, Exposure 1, or per MFMA flooring manufacturer design. The subfloor is generally installed at 45 and 90 degree angles to the direction of the finished maple surface. Resilient pads are mechanically fastened to the underside of the bottom layer of plywood and are generally spaced at one foot intervals (32 per plywood sheet). The surface maple, plywood and pads are installed over a seam-sealed 6 mil polyethylene vapor retarder.

Basket Weave Floor System

This system consists of an all wood subfloor “weaved together” in a way to provide resilience and stability.