What Plywood Do You Use For Subfloor?

Choosing the right plywood for subflooring is crucial for creating a stable, durable foundation for your finished flooring. Here’s a comprehensive guide to help you select the best plywood for your subflooring project.

Check out our Plywood Products

Types of Plywood for Subflooring

Let’s start with plywood grades.

1. CDX Plywood

Best for: Standard subflooring in dry, interior areas

Features:

• “C” grade face, “D” grade back, exposure-rated glue (“X”)
• Economical choice for most residential subflooring
• Suitable for areas that will be covered with finish flooring

Check out our CDX Plywood

Order now: Quote Request

2. Exterior Plywood

Best for: Subflooring in potentially damp areas (basements, bathrooms)

Features:

• Water-resistant glue for better moisture resistance
• More durable than standard CDX in humid conditions
• Suitable for areas with higher moisture exposure

Check out our Exterior Plywood

Order now: Quote Request

3. Tongue and Groove Plywood

Best for: High-performance subflooring, especially in high-traffic areas

Features:

• Interlocking edges for added stability and reduced movement
• Minimizes squeaking and helps create a more rigid floor system
• Often available in CDX or better grades

4. OSB (Oriented Strand Board)

Best for: Cost-effective subflooring in dry areas

Features:

• Made from wood strands arranged in layers and bonded with resin
• Generally less expensive than plywood
• Suitable for use under most types of finished flooring

Thickness Considerations for Subflooring

The appropriate thickness depends on the joist spacing and local building codes:

• 5/8 inch (15 mm): Minimum thickness, suitable for joist spacing up to 16 inches (40 cm)
• 3/4 inch (18 mm): Recommended for joist spacing up to 24 inches (60 cm)
• 7/8 inch (22 mm) or 1 inch (25 mm): Used for maximum strength and stability, often in high-end or commercial applications

Factors to Consider When Choosing Subflooring Plywood

1. Joist Spacing: Wider joist spacing requires thicker plywood for adequate support.
2. Moisture Exposure: Choose moisture-resistant options for areas prone to dampness.
3. Load Requirements: Consider the expected load on the floor (e.g., heavy furniture, foot traffic).
4. Finish Flooring Type: Some finish flooring materials may require specific subfloor characteristics.
5. Building Codes: Always check local building codes for minimum thickness and grade requirements.
6. Sound Insulation: In multi-story buildings, consider the impact on sound transmission.

Installation Tips for Subflooring Plywood

1. Acclimate the plywood to the installation environment for at least 48 hours before installation.
2. Leave a 1/8 inch (3 mm) gap between plywood sheets to allow for expansion.
3. Stagger the plywood joints for increased floor strength.
4. Use ring-shank nails or screws designed for subflooring applications.
5. Apply a bead of construction adhesive to the joists before laying the plywood for added stability and to reduce squeaking.
6. For tongue and groove plywood, ensure the grooved edge faces the wall and the tongue faces the center of the room.
7. Sand any uneven seams between sheets to create a level surface for the finish flooring.

Special Considerations

• Radiant Heat Systems: If installing over a radiant heat system, consult with the manufacturer for compatible subflooring recommendations.
• Existing Subfloors: When renovating, inspect the existing subfloor for any signs of damage, rot, or unevenness. Address these issues before installing new flooring.
• Underlayment: Some finish flooring types may require an additional layer of underlayment over the subfloor.
• Green Building: For environmentally conscious projects, look for plywood certified by organizations like FSC (Forest Stewardship Council).

Visit our shop: we have the right size and type of plywood to meet your needs in the Canadian market.