How to Lay Tile on a Plywood Subfloor


Installing tile on a plywood subfloor can transform a room and add beautiful, durable surfacing. With proper preparation and technique, you can achieve stunning results. Laying tile on plywood has some specific considerations compared to concrete or other substrates. Following essential steps like assessing the subfloor, preparing the surface, selecting quality materials, and using proper installation methods will ensure success.

This comprehensive guide covers everything you need to know to professionally lay tile on a plywood subfloor. We’ll discuss how to prepare the plywood, choose appropriate tiles and setting materials, use proper installation techniques, grout and seal the tiles, and maintain the finished tile floor. With these tips, you’ll gain the knowledge and confidence to tile over plywood flawlessly.

Assessing the Plywood Subfloor

The first step is evaluating the plywood subfloor. Plywood provides a cost-effective, stable surface for installing tile once properly prepared. Here’s what to check:

Type of Plywood

Use interior plywood like lauan or CDX rather than exterior grades. Look for a thickness of at least 3/4” tongue and groove plywood with a maximum 12” spacing between joists according to TCA guidelines. Thicker 19/32” or 5/8” plywood is ideal for a very flat, rigid subfloor.

Moisture Content

Measure moisture content using a probe meter, ensuring it is below 12% throughout. High moisture can damage adhesive bonds.


Use a straightedge to check for flatness, addressing any areas over 1/8” deviation in 10 feet.

Secure Attachment

Nail or screw sheets every 6” along joists to avoid squeaking or movement. Glue together tongue and groove edges.

Clean Surface

Clean the plywood completely before tile prep, removing construction debris, dust, oils, or existing floor coverings.

If moisture, flatness, or stability issues exist, methods like sealing concrete backerboard can help strengthen the subfloor before tiling.

Preparing the Plywood Subfloor

With a suitable plywood identified, proper prep is crucial for successful tile installation. Here are key steps:

Fill Cracks and Holes

Fill any cracks, holes, and imperfections with a polymer-modified patching compound. Allow it to fully cure.

Install Cement Backerboard

Screw 1/4”-1/2” cement backerboard like Durock or Hardiebacker to the plywood with recommended fasteners and spacing. Use thinset to fill all seams and corners. This strengthens the surface while providing moisture protection.

Skim Coat with Thinset

Apply a skim coat layer of thinset mortar with a 1/4” V-notched trowel to flatten the surface. Allow thinset to fully cure before tiling.

Apply Sealer or Membrane

Roll on a primer coat and liquid waterproofing membrane intended for plywood subfloors. This seals the surface and blocks moisture.

Install Crack Isolation Layer

Adding a crack suppression mat or underlayment provides an additional moisture barrier while allowing slight subfloor movement without affecting tile above.

With the plywood prepped, you can move on to selecting tiles and setting materials.

Choosing Appropriate Tile and Setting Materials

The tile itself along with mortars and grouts require careful consideration, as the products must be suitable for the plywood subfloor and match your design vision.

Tile Options

  • Ceramic – Classic option available in endless colors, patterns, and textures. Suitable for floors and walls.
  • Porcelain – Low water absorption and high durability. Withstands moisture well. Ideal for high traffic areas.
  • Natural Stone – Elegant, decorative tiles like marble, granite, or slate. Requires extra care to seal and maintain.
  • Glass/Mosaic – Intricate decorative tiles that require high adhesion mortars. Better for walls than floors.

For plywood subfloors, avoid large format or heavy stone tiles. Lighter ceramic or porcelain 12” tiles or smaller are best.

Mortar Options

  • Dry-set (thinset) – Cement-based mix used in most tile installations provides excellent adhesion. Look for polymer-modified thinset for added flexibility.
  • Epoxy mortar – Two-part epoxy with extremely high bond strength. Used for glass or challenging substrates.
  • Organic adhesive (mastic) – Pre-mixed adhesive suitable only for wall tiles, not floors.

Use a high quality polymer-modified mortar rated for the tile type and size. White thinset allows checking adhesive coverage beneath tiles.

Grout Considerations

Choose an appropriate grout for the tile and environment. Unsanded grout is best with narrow tile joints under 1/8”. Sanded grout stands up better to foot traffic. Grout release aids application for polished tiles. Match grout color to your tile color.

With proper products selected, focus shifts to installation techniques.

Using Correct Installation Techniques

Applying tiles successfully on the prepared plywood involves careful techniques and workmanship.

Setting Tile Layout

  • Mark the central point and snap perpendicular reference lines on the floor defining the boundaries of the tile installation area.
  • Dry lay tiles to determine optimal layout and pattern with balanced cuts at perimeter.
  • Mix thinset mortar according to directions. Let slake 5-10 minutes for best workability.

Applying Thinset and Tiles

  • Use the proper trowel notch size to achieve full mortar contact under tiles. Hold at 45° angle spreading thinset.
  • Apply mortar in sections that can be tiled before skinning occurs, typically 3-4 ft areas.
  • Set tiles firmly with a twisting motion pressing into thinset. Use tile spacers for consistent joints.
  • Check tiles periodically to confirm 100% coverage and proper depth. Adjust as needed.
  • Tap down uneven tiles using a rubber mallet. Do not disturb placed tiles after mortar begins curing.

Cutting Tiles

  • Use a wet saw with a quality diamond blade to accurately cut perimeter and hole-cutting tiles.
  • For small adjustments, use a carbide scoring tool and tile nippers. Use an angle grinder for notches and relief cuts.

Cut edges should be free of chipping or rough areas. Blend cut edges into patterns.

With tile installation complete once thinset has cured per manufacturer specifications, grouting and finishing steps remain.

Grouting and Finishing the Tiled Floor

Applying durable grout fills the joints and puts the final touch on the tile installation.

Grouting Steps

  • Allow thinset to fully cure before grouting, typically 24 hours.
  • Apply grout release or sealer on polished or porous tiles to prevent staining.
  • Mix and apply grout according to package directions using a rubber grout float. Hold float at a 45° angle spreading into joints.
  • Allow grout to slightly set up, typically 10-15 minutes. Then scrub joints at a 90° angle to remove excess grout.
  • Clean tiles diagonally using minimal water and frequent rinse buckets to limit grout haze and color variation.
  • Allow grout to fully cure per manufacturer instructions before light use, around 3 days.

Caulking Joints

  • Apply flexible silicone caulk in expansion joints, window/door frames, and floor/wall change of plane joints.

Sealing and Protecting

  • Apply grout sealer once fully cured to resist staining. Use stone sealer on porous natural stone tiles.
  • Do not expose floor to heavy foot traffic, standing moisture, or cleaning for 14 days minimum after installation.

With proper grouting and curing, the finished tile floor will provide years of duriance, optimized by effective maintenance.

Maintaining the Tile Floor

Protect your tile investment with proper care. Here are some tips:

  • Sweep or vacuum regularly to remove dirt and grit that can abrade tile or dull the finish
  • Use damp mopping with neutral pH cleaner for routine cleaning. Avoid harsh chemicals.
  • Reapply sealer annually or as needed based on wear to boost stain resistance.
  • Address new cracks or damage promptly through tile replacement to prevent moisture issues.
  • Do not use wax or treatments designed for vinyl or wood floors which can damage tile.

By following manufacturer maintenance guidelines, your tile floor will maintain its beauty for decades to come.

Frequently Asked Questions

Here are answers to some common questions about laying tile on plywood:

What are the benefits of using plywood instead of concrete?

Plywood provides a cost-effective subfloor material that avoids the higher cost of concrete substrate installation. It also allows tiling on upper story floors where concrete is not feasible. Plywood offers a smooth, stable surface once properly prepared.

Can I tile directly on OSB or particle board?

No, OSB and particle board are not suitable subfloors for direct application of tile. Always use a minimum 3/4” plywood or cement backerboard underlayment when tiling over these substrates.

What issues can occur when tiling on improperly prepared plywood?

Poor adhesion, cracks, tile popping, and moisture-related problems can result if the plywood subfloor is not flat, securely fastened, and protected from moisture penetration.

Should I use backerboard on plywood before tiling?

Yes, installing cement backerboard like Durock provides critical reinforcement that strengthens floors before tiling over plywood. When properly fastened and seam-sealed, it creates a durable surface designed for tile.

Can I tile a plywood floor even if some boards are slightly uneven?

Minor variations under 1/8” in 10 feet can be smoothed with a skim coat layer of thinset. For more significant unevenness, use a self-leveling underlayment to flatten the plywood before applying tile.

Why is a waterproofing membrane recommended?

Plywood is vulnerable to moisture damage that can undermine tile bonding over time. Applying a liquid-applied sealer and membrane specifically formulated for plywood provides an added layer of waterproof protection.


Installing tile on a plywood subfloor brings unique benefits and considerations compared to concrete or other substrates. With careful surface preparation, quality materials, proper installation techniques, and ongoing maintenance, you can achieve stunning, durable tiled floors over plywood. Following the recommendations in this guide will set you up for success tiling over plywood substrates.