DAANIS: Plywood Subfloor Rating

Plywood Subfloor Rating

For touch sanded grades such as c d plugged c c plugged underlayment and apa rated sturd i floor marked ps 1 see table 2. When used for roofing plywood panels are covered and protected by a variety of building materials that keep the elements at bay including roof felt underlayment flashing and shingles.

Glossary Wood University

The thickness of plywood panels in a subfloor is regulated by the spacing of the joists.

Plywood subfloor rating. This number is known as a span rating. Plywood span ratings indicate the distance between framing members for roofing and flooring. Underlayment is recommended for use with rated sheathing.

When used in flooring plywood functions as the subfloor that supports hardwoods tile and carpet floors. Span rating sizes and availability basic specifications general provisions roof sheathing flooring panel handling and storage 9 floors plywood floor components 10 floor span combination subfloorunderlayment subflooring non span rated plywood. When installing a plywood subfloor on top of the slab at grade the thickness is governed by how long the fasteners for the flooring will be.

Plywood that is five eighth inch thick also available for flooring but using it restricts joist spacing and the types of finished flooring. Underlayments special face and inner ply construction resists dents and punctures from concentrated loads. Ratings grades sizes.

Table 1 applies to unsanded plywood and is based on apa rated sheath ing marked ps 1 grade. The subfloor rests directly on the floor joists and is the lowest layer of flooring material. Some professionals however will use plywood as thin as 14 inch for resilient flooring if the subfloor is in particularly good condition.

A final mark to check is the thickness of the plywood. Apa trademarked plywood is suitable for a variety of end uses including subflooring single layer flooring wall and roof sheathing sheathing ceilingdeck structural insulated panels marine applications siding webs of wood i joists concrete forming pallets industrial containers mezzanine decks and furniture. Plywood three quarters inch thick is the most common and the strongest.

The enhanced plywood or osb installation should survive exposure to moisture meaning builders likely wont need to install a partial replacement or second subfloor in order to install finish. The span rating looks similar to a fraction and gives the roof span first and the floor span second. Table 3 applies to sanded grades such as a d and b d.

Most underlayment approved plywood is at least 1132 inches the standard recommendation. Underlayment is a special grade of apa plywood that is attached on top of the subfloor to provide a durable and resistant layer under finish flooring.

1 1 8 X 4 X 8 Exposure 1 Rated Osb Tongue Groove Subflooring