Best Plywood for Every Use - Complete Guide
Learn which plywood grade, type, and thickness to use for subfloors, cabinets, furniture, outdoor projects, and more. Includes OSB comparison and defects to avoid.
Dr. Snezana Lawrence
Mathematical Historian
15+ years experience
PhD from Yale University. Published mathematical historian ensuring precision in all calculations.
Education
PhD in Mathematical History - Yale University
Bruce Zawalsky
Survival & DIY Expert
28+ years experience
28+ years wilderness survival and hands-on construction experience. Author of "Canadian Wilderness Survival."
Education
Canadian Armed Forces Wilderness Survival Training
Quick Answer
Subfloor/Sheathing: 3/4" CDX ($25-40). Cabinets: 3/4" cabinet-grade or Baltic birch ($50-100). Furniture: Baltic birch or hardwood plywood. Outdoor: Marine or pressure-treated. Always inspect for voids at edges before buying!
Quick Plywood Selection Guide
Structural/Hidden
CDX Plywood
C-D grade with exterior glue. Standard for subfloors, roof/wall sheathing. Economical, strong, handles moisture exposure during construction.
Furniture/Cabinets
Baltic Birch or Cabinet Grade
Void-free construction, beautiful edges, excellent screw holding. Worth the premium for visible applications and fine woodworking.
Outdoor/Marine
Marine or Pressure-Treated
Waterproof glue, no voids (marine), or chemical treatment (PT). Essential for docks, boats, outdoor furniture, ground contact.
Understanding Plywood Grades
Plywood grades describe the quality of the face and back veneers. A panel marked "A-C" has an A-grade face and C-grade back. The grade you need depends on visibility - use higher grades for visible surfaces, lower grades for hidden structural applications.
Face/Back Grades (A through D)
| Grade | Quality | Description | Best For | Cost |
|---|---|---|---|---|
| A | Premium | Smooth, sanded, paintable. Few if any patches, no knots. Highest quality face veneer. | Furniture, cabinets, visible surfaces | $$$ |
| B | Good | Solid surface with minor repairs allowed. Small knots and patches permitted. Sanded smooth. | Paint-grade cabinets, utility furniture, one visible side | $$ |
| C | Utility | Knotholes up to 1.5", limited splits allowed. May have patches and repairs. Unsanded. | Sheathing, subfloor, hidden structural | $ |
| D | Economy | Larger knotholes up to 2.5", more defects allowed. Roughest grade. Not for exposure. | Backing, interior sheathing, temporary use | $ |
Common Grade Combinations
| Code | Description | Typical Use |
|---|---|---|
| A-A | Both faces premium grade. Highest quality, both sides visible. | Cabinet doors, fine furniture |
| A-B | Premium face, good back. One side showcase quality. | Furniture tops, cabinet sides |
| A-C | Premium face, utility back. Exterior glue standard. | Exterior siding, soffits |
| B-B | Good quality both sides. Economical paint-grade option. | Utility cabinets, shelving |
| B-C | Good face, utility back. Mid-range exterior option. | Exterior sheathing, shop projects |
| C-D (CDX) | Utility face, economy back. "X" = exterior glue. | Subfloor, roof sheathing |
💡 The "X" in CDX
The "X" in CDX stands for "exterior glue" - NOT exterior grade. It means the glue is water-resistant for construction exposure, but the panel itself is not rated for permanent outdoor use. For true exterior applications, look for panels stamped "EXTERIOR" or use marine/pressure-treated plywood.
Plywood Thickness Guide
| Nominal | Actual | Plies | Common Uses | Span/Support |
|---|---|---|---|---|
| 1/4" (6mm) | 0.219" | 3 | Cabinet backs, drawer bottoms, craft projects, underlayment | Must be fully supported |
| 3/8" (9mm) | 0.344" | 3-5 | Furniture backs, small shelves, light-duty applications | Light loads, 12" spans |
| 1/2" (12mm) | 0.469" | 5 | Wall sheathing, roof sheathing (24" OC), interior shelving | 24" joist spacing (wall) |
| 5/8" (15mm) | 0.578" | 5-7 | Underlayment, cabinet sides, stronger shelving | 16-24" spans |
| 3/4" (18mm) | 0.703" | 7 | Subfloor, heavy shelving, cabinet boxes, furniture, workbenches | 16" joist spacing |
| 1" (25mm) | 1.0" | 9+ | Heavy-duty subfloor, industrial applications, thick countertops | 24"+ joist spacing |
⚠️ Important: Actual vs Nominal Thickness
"3/4 inch" plywood is actually 23/32" (0.719"). This matters when cutting dadoes and rabbets for joinery. Import plywood (like Baltic birch) often uses true metric dimensions (18mm = 0.709"), which is even thinner.
1/4" nominal
Actual: 7/32" (0.219")
1/2" nominal
Actual: 15/32" (0.469")
3/4" nominal
Actual: 23/32" (0.719")
Baltic Birch 18mm
Actual: 0.709"
Plywood Types Compared
Softwood Plywood (CDX, BCX)
$25-45/sheetCore
Pine, fir, spruce veneers
Glue
Exterior (CDX) or Interior
Best Use
Subfloors, sheathing, construction projects
✓ Pros
- • Economical
- • Strong
- • Widely available
- • Good for structural
✗ Cons
- • Visible voids
- • Poor edge appearance
- • Rough surface
Hardwood Plywood
$40-80/sheetCore
Hardwood or softwood with hardwood face
Glue
Usually interior
Best Use
Cabinets, furniture, visible applications
✓ Pros
- • Beautiful face veneer
- • Takes stain well
- • Smooth surface
✗ Cons
- • More expensive
- • Limited sizes
- • Face chips easily
Baltic Birch
$50-100/sheet (5×5)Core
All-birch void-free plies
Glue
Exterior
Best Use
Fine furniture, CNC work, jigs, shop furniture
✓ Pros
- • Void-free
- • Beautiful edges
- • Superior strength
- • Holds screws excellently
✗ Cons
- • Expensive
- • 5×5 size (not 4×8)
- • Heavy
- • Limited availability
Marine Plywood
$70-150/sheetCore
Void-free throughout
Glue
Waterproof
Best Use
Boat building, docks, permanent water exposure
✓ Pros
- • No voids any ply
- • Waterproof glue
- • Highest quality construction
✗ Cons
- • Very expensive
- • NOT rot-resistant (needs sealing)
- • Overkill for most projects
Pressure-Treated Plywood
$40-60/sheetCore
Usually softwood
Glue
Exterior
Best Use
Outdoor structures, ground contact, landscaping
✓ Pros
- • Rot resistant
- • Insect resistant
- • Ground contact rated
✗ Cons
- • Chemicals (wear gloves)
- • Harder to finish
- • Can corrode fasteners
MDO (Medium Density Overlay)
$45-70/sheetCore
Softwood with resin overlay
Glue
Exterior
Best Use
Signs, exterior paint surfaces, concrete forms
✓ Pros
- • Super smooth surface
- • Excellent paint adhesion
- • Weather resistant
✗ Cons
- • Can't be stained
- • Overlay can delaminate
- • Limited uses
Sanded Plywood
$35-55/sheetCore
Softwood with sanded faces
Glue
Interior or exterior
Best Use
Painted furniture, shelving, utility projects
✓ Pros
- • Smooth surface
- • Paintable
- • Economical finished look
✗ Cons
- • Thin face veneer
- • Voids may show
- • Limited stain quality
Best Plywood by Application
| Application | Recommended Type | Thickness | Notes |
|---|---|---|---|
| Subfloor | 3/4" CDX or Sturd-I-Floor | 23/32" (3/4") | Tongue-and-groove reduces squeaks. Use construction adhesive + screws. Glue/screw pattern critical. |
| Roof Sheathing | 1/2" or 5/8" CDX | 15/32" or 19/32" | Check local code for thickness requirements. H-clips between panels. Stagger joints. |
| Wall Sheathing | 1/2" CDX or OSB | 15/32" | OSB acceptable here. Structural sheathing adds racking strength. May need vapor barrier. |
| Cabinet Boxes | 3/4" Cabinet-grade or Baltic Birch | 18mm (3/4") | Use 1/2" for backs. Pre-finished plywood available. Baltic birch edges beautiful without banding. |
| Shelving | 3/4" hardwood plywood | 18mm+ (3/4"+) | Limit spans to 36" without support. Edge band for finished look. 1/2" for light loads only. |
| Furniture | Baltic Birch or Hardwood Plywood | Varies (3/4" typical) | Match wood species to project. Baltic birch for painted. Consider veneer for special species. |
| Drawer Boxes | 1/2" Baltic Birch | 12mm (1/2") | Baltic birch standard for quality drawers. Use 1/4" for bottoms. Dovetail or box joints. |
| Workbench Top | 3/4" Baltic Birch (doubled) | 1.5" (two layers) | Glue two sheets together for 1.5" top. Edge-glued solid wood also works. Needs flat, stable surface. |
| Outdoor Projects | Marine or Pressure-Treated | 3/4" typical | Marine for appearance, PT for structure. Always seal/paint. Use stainless steel fasteners. |
| Underlayment | 1/4" or 1/2" Underlayment-grade | 1/4" over existing subfloor | Creates smooth surface for vinyl/carpet. Fill and sand all imperfections. Not structural. |
OSB vs Plywood Comparison
| Property | Plywood | OSB | Winner |
|---|---|---|---|
| Cost | $35-50/sheet | $25-35/sheet | OSB |
| Moisture Resistance | Swells less, dries faster | Swells significantly, slow to dry | Plywood |
| Strength (bending) | Slightly weaker | Slightly stronger | Tie |
| Screw Holding | Excellent, edges included | Good in field, poor at edges | Plywood |
| Stiffness | Consistent | Can feel bouncy | Plywood |
| Edge Quality | Smooth, cuttable | Rough, chips easily | Plywood |
| Availability | Good | Excellent | OSB |
| Environmental | More old-growth trees | Uses smaller/younger trees | OSB |
When to Use Each
| Application | Verdict |
|---|---|
| Wall sheathing | OSB acceptable - stays dry behind siding |
| Roof sheathing (dry climate) | OSB acceptable - but plywood preferred |
| Subfloors | Plywood preferred - better moisture handling, screw holding |
| Cabinets/furniture | Always plywood - OSB too rough, poor edges |
| Outdoor use | Always plywood - OSB swells terribly |
💡 Bottom Line
Use OSB when it will stay dry and you need to save money (wall/roof sheathing). Use plywood for subfloors (better screw holding), any moisture exposure, and all visible or furniture applications. The extra cost of plywood is usually worth it for any application where quality or longevity matters.
Plywood Defects to Avoid
Voids/Core Gaps
What It Is
Empty spaces between plies visible at edges
Impact
Weakens panel, poor screw holding, visible in cut edges
How to Check
Look at edges carefully before buying. Tap panel - hollow sound indicates voids.
Delamination
What It Is
Plies separating, often at edges or corners
Impact
Panel will fail, cannot be repaired, indicates glue failure
How to Check
Flex panel slightly, look for separation. Check corners and edges.
Warping/Bowing
What It Is
Panel not flat - cups, twists, or bows
Impact
Difficult to use, won't lay flat, affects finished project
How to Check
Sight down length. Stand panel on edge to check for rock.
Face Veneer Damage
What It Is
Chips, gouges, or tears in face veneer
Impact
Visible in finished work, can't be fully repaired
How to Check
Inspect face in good light. Run hand across surface.
Moisture Damage
What It Is
Water stains, swelling, soft spots
Impact
Permanent damage, weakens panel, causes finish issues
How to Check
Look for discoloration. Press suspect areas. Check stored panels.
Excessive Knots (A/B grade)
What It Is
More knots than grade allows
Impact
Indicates misgraded panel, affects appearance and value
How to Check
Count knots, compare to grade specifications. Know what you're buying.
Plywood Buying Tips
Inspect Before Buying
Pull sheets from the stack to check. Don't accept the top sheet (usually damaged). Check edges for voids.
Understand Actual Thickness
3/4" plywood is actually 23/32" (0.72"). This matters for dadoes and joints. Import plywood may be true metric.
Buy Extra
Plan for 10-15% waste from cuts and defects. Better to have extra than make another trip.
Store Properly
Keep flat on supports. Leaning causes warp. Keep dry. Acclimate to workspace before use.
Match Grain Direction
Face grain runs along the 8' dimension typically. Plan cuts to use grain direction advantageously.
Consider Pre-Finished
Pre-finished plywood saves time for cabinets. More expensive but eliminates finishing steps.
🛒 Where to Buy Quality Plywood
Big Box Stores
Good for CDX, basic plywood. Inspect carefully - high turnover but handling damage common.
Lumber Yards
Better selection, quality grades. Staff more knowledgeable. Worth the trip for projects.
Specialty Suppliers
Best for Baltic birch, marine, exotic veneers. Higher prices but highest quality.
Frequently Asked Questions
What is the difference between CDX and BCX plywood?
CDX has a C-grade face and D-grade back - standard for sheathing that will be covered. BCX has a B-grade face (smoother, fewer patches) and C-grade back - better for applications where one side might be visible like soffits. Both use exterior glue (the "X"). BCX costs about 20-30% more than CDX.
Is OSB as good as plywood?
For structural sheathing (walls/roofs) that stays dry, OSB is acceptable and cheaper. However, plywood is better for subfloors (holds screws better), any moisture exposure (doesn't swell as much), and all furniture/cabinet work. OSB edges chip badly and can't be routed. Use plywood when quality matters.
What thickness plywood for subfloor?
3/4" (23/32") is standard for subfloors with joists 16" on center. Use 7/8" or double-layer 1/2" for 24" joist spacing. Always use tongue-and-groove panels to reduce squeaking. CDX or "Sturd-I-Floor" rated panels are standard. Use construction adhesive plus screws, not nails.
What is marine grade plywood?
Marine plywood uses waterproof (not just water-resistant) glue and has absolutely no voids in any ply - even interior plies are void-free. It's designed for boat building where water saturation occurs. Important: marine plywood is NOT rot-resistant - it still needs to be sealed and maintained. It's expensive ($70-150/sheet) and overkill for most outdoor projects.
Why is Baltic birch plywood so expensive?
Baltic birch has more plies (13 in 3/4" vs 5-7 in standard), completely void-free construction, and uses birch throughout (not just face veneer). The edges are beautiful and don't need banding. It holds screws extraordinarily well and is ideal for CNC routing. The quality justifies the 2-3× price for drawer boxes, fine furniture, jigs, and shop furniture.
This guide has been reviewed by multiple experts to ensure both technical accuracy and practical application.
Dr. Snezana Lawrence
Mathematical Historian | PhD from Yale
Dr. Lawrence is a published mathematical historian with a PhD from Yale University. She ensures mathematical precision and accuracy in all our calculations, conversions, and academic score calculators. Her expertise spans computational mathematics and educational assessment.
LinkedIn ProfileBruce Zawalsky
Survival & DIY Expert | 28+ Years Experience
Bruce is a wilderness survival expert with 28+ years of experience and author of "Canadian Wilderness Survival." His extensive hands-on experience in building wilderness shelters, construction projects, and practical DIY work, combined with his military training, ensures all our construction guides and survival content are field-tested and practical.
LinkedIn Profile