How to Choose the Correct Tile Adhesive or Mortar

Choosing the right tile adhesive or mortar is crucial for a successful tiling project. The tile adhesive or mortar acts as the glue that bonds the tiles to the substrate surface. Using the wrong type can result in tiles that crack, dislodge, or completely debond from the surface.

There are many factors to consider when selecting tile adhesive such as:

  • Type of tile material
  • Substrate material
  • Environmental conditions
  • Performance requirements

Understanding these key factors will ensure you choose the optimal product for a long-lasting and high quality tile installation.

Tile Material

The type of tile you are installing plays a significant role in determining the appropriate adhesive. Tiles come in a wide range of materials including:

Ceramic and Porcelain

Ceramic and porcelain tiles are one of the most popular choices for floors and walls. They are durable, available in countless styles, and relatively affordable.

For ceramic and porcelain tiles, a cement-based mortar is recommended. Cement mortars provide a strong bond and are suitable for interior and exterior installations. Popular choices include:

  • Thin-set mortar – modified with polymer additives to improve adhesion. Thin-set contains a mixture of cement, sand, and additives. It is used to bond tile to surfaces like cement backer board, concrete, and existing tile.
  • Medium bed mortar – thicker than thin-set with more adhesive power. It can be used for tiles with slight irregularities on the back side.
  • Mortar bed – the thickest type used to build and level a mortar substrate then bond tile on top. Often used for large format tiles like 12″x24″ sizes.

Natural Stone

Natural stone tiles like marble, travertine, slate, and granite have unique properties that require specific adhesives. Stone tiles can be sensitive to moisture and prone to cracking and staining.

It’s recommended to use a white polymer-fortified mortar. White mortar highlights any spots or residue for easier clean-up. The polymer additives provide strong adhesion and flexibility to accommodate the natural movement of stone. Epoxy adhesives are another excellent choice for a durable, water-resistant bond.


Glass tile and mosaic sheets provide a gorgeous translucent effect but require special handling. To bond glass tile properly without cracking, use a two-part reactive resin epoxy. Epoxy has incredibly strong adhesion for heavy and smooth surfaces like glass.

Metal Tile

Metal tile brings sleek, contemporary style perfect for backsplashes and accent walls. Always use a two-part epoxy specifically designed for metal and glass. The epoxy fills any pores or irregularities on the back of metal tile for optimal contact.

Substrate Material

Consider the surface you are bonding tile to when selecting mortar. The substrate must be properly prepared and provide a compatible surface.


Concrete is commonly used for floors and subfloors. New poured concrete requires a 3-4 week curing period before tiling. For best adhesion, use a polymer-modified thin-set for concrete. Acrylic additives allow for slight flexibility.

Cement Backer Board

Cement backer board is the preferred substrate for tiled wet areas like showers. These cement boards provide stability and water resistance. Thin-set mortar formulated for cement board will bond the tile firmly.

Existing Tile

Retiling over existing tile requires special preparation. The old tile must be firmly attached to its substrate and free of any waxes or sealants. Use a high quality modified thin-set to properly bond new tile. An adhesion promoter should also be applied to the existing tile before installation.


Wood sheets and boards are common substrates for interior floors and walls. However, wood expands and contracts with changes in moisture and temperature. To compensate, use a mortar with latex or epoxy additives which adds flexibility. The wood must also be treated and properly prepared beforehand.

Plaster and Drywall

Plaster and drywall are not suitable substrate materials for tile or stone. They can easily deteriorate or crumble when exposed to moisture. It’s recommended to use a mortar bed or cement board over drywall or plaster before tiling.

Environmental Conditions

Tile mortars are affected by conditions like humidity, temperature, and exposure to weather. Choose a mortar suitable for the environment the tiled surface will exist in.

Indoor vs. Outdoor

Indoor and outdoor installations have different requirements:

  • For indoor use, standard polymer-modified thin-set provides a strong bond.
  • For exterior applications, use a mortar blend formulated for outdoor use. These have cement-based reactive resins to better handle weather, pool water, freezing temperatures and other challenges.

Hot or Cold Climate

In extremely hot or cold climates, look for mortar with high adhesion and flexibility. For example hot areas may call for an epoxy mortar while cold climates would benefit from latex-polymer modified blends.

Wet Areas

Showers, swimming pools, and fountains with direct water contact need waterproof performance. Use a waterproof epoxy mortar or special waterproof grout. Cement-based mortars absorb moisture and can lead to damage.

Performance Requirements

Consider the required performance and durability characteristics for the tile installation:

Heavy Tile or Stone

Large format tiles, stone slabs, and dimensional mosaics require extra adhesive power. Use a medium bed or epoxy mortar to safely bear heavier loads.

High Traffic

For high traffic floors like malls or office lobbies, maximum strength and durability is vital. Use modified mortars with high bond strength to avoid loosening and cracks under heavy foot traffic.

Quick Setting

Some projects require the tile be grouted or exposed to foot traffic shortly after installation. A rapid setting mortar gains strength quickly for faster return to service.

Adjustable Work Time

Pros prefer mortars with at least 30 to 45 minutes of adjustability. This allows time to properly position tiles after initial placement. Pick mortars with an appropriate set time for your skill level and project scope.

Choosing an Approved Manufacturer

With hundreds of tile mortar products available, narrow your selection by choosing top manufacturers. Respected brands like MAPEI, Laticrete, Custom, and Bostik have extensive testing and experience developing quality adhesives.

Always check product specs and confirm suitability for your specific tile and project type. Ask retailer professionals for recommendations on trusted brands carried in their store.

Additional Tips for Choosing Tile Adhesive

Follow these tips for choosing the optimal tile mortar:

  • Read all package directions carefully and follow the manufacturer’s recommended uses. Don’t substitute a different type not designed for your tile material or project location.
  • Mortars come in different grades based on amount of polymer additive. Higher grades have increased adhesion and performance.
  • Match change in plane movement specs between tile and mortar to allow for expansion and contraction.
  • Select the appropriate trowel size to achieve the proper adhesive thickness behind tiles. Bigger tiles require deeper mortar beds.
  • Consider mortars with antimicrobial product protection to inhibit mold, mildew, and bacteria growth.
  • Store mortar in ideal conditions before use – away from moisture, direct sunlight, and extreme temperatures.
  • Always mix per directions and allow thorough wetting and slaking of mortar prior to application on substrate.

Using the correct installation methods and following the manufacturer’s specifications for your selected mortar will lead to long-lasting and professional tile results. Don’t cut corners on this vital bonding material.

How to Choose the Correct Tile Adhesive or Mortar

Selecting the right tile adhesive or mortar for your specific tile installation is a key step for success. This article will outline the critical factors in choosing the correct adhesive product for durable and high quality tile results.

The tile adhesive bonds the tile to the installation surface, so its characteristics must match the demands of the project. With hundreds of mortar products available, understanding the following criteria will ensure you select the optimal adhesive:

Tile Material

Tiles come in a range of materials – each with their own bonding needs:

  • Ceramic/Porcelain – Cement-based mortars provide strong adhesion. Popular choices include thin-set, medium bed, and mortar beds.
  • Natural Stone – Requires white polymer-modified or epoxy mortars. Flexible to handle stone movement. Resists moisture and staining.
  • Glass – Use reactive resin two-part epoxy for smooth and rigid glass tiles. Excellent adhesion and moisture resistance.
  • Metal – Also requires two-part epoxy designed for use with metal and glass tiles. Fills pores for full contact.

Substrate Material

Consider surface being tiled:

  • Concrete – Polymer-modified thin-set provides excellent concrete adhesion. Allows for minor flexibility.
  • Cement Board – Thin-set designed for cement backer boards bonds firmly. Provides stability and waterproofing.
  • Existing Tile – Use high quality modified mortar. Apply adhesion promoter first for optimal bond with old tile.
  • Wood – Requires latex or epoxy additive for flexibility. Wood expands/contracts and must be pre-treated.
  • Drywall/Plaster – Not suitable substrates. Requires mortar bed or cement board overlay first.

Environmental Conditions

Mortar choices vary based on project location environment:

  • Indoor vs. Outdoor – Outdoor installations demand weatherproof cement-based reactive resin products. Indoor allows standard modified blends.
  • Hot/Cold Climates – Use mortars with high adhesion and flexibility like epoxy or latex polymer versions.
  • Wet Areas – Require waterproof epoxy or grout. Cement-based mortars absorb moisture.

Performance Requirements

Consider durability and performance needs:

  • Heavy Tile or Stone – Use medium bed or epoxy mortars to support heavier loads.
  • High Traffic – Maximum strength modified mortars avoid cracks and loosening under traffic.
  • Quick Setting – Rapid products gain strength quickly for faster return to service.
  • Adjustable Work Time – Look for adequate workability time before set for positioning.

Approved Brands

Stick with respected manufacturers like MAPEI, Laticrete, Custom, Bostik. Confirm suitability for your specific project.

Additional Tips

Follow manufacturer directions. Higher polymer grades offer increased performance. Match movement specs between tile and mortar. Choose proper trowel size for adhesive thickness needs. Consider antimicrobial formulas. Store correctly before use. Test mixing methods beforehand.

Frequently Asked Questions About Choosing Tile Adhesives and Mortars

Below are answers to some frequently asked questions about selecting the proper tile adhesive or mortar:

How do I know which mortar to use with large format tiles?

For tiles with lengths 15 inches or larger, use a medium bed mortar at a minimum thickness of 3/8 inch. The thicker mortar layer provides more support and better adhesion across the entire tile backing.

Can I use the same thin-set for floor and wall tile installation?

Generally, yes – thin-set mortars formulated for floors meets the demands of wall applications. However, review manufacturer specifications to confirm suitability for both floor and wall use.

How long is bagged mortar good for after opened?

Most standard mortars must be used within 1 year of manufacture date if kept sealed and stored properly. High polymer modified mortars have shorter 6 month shelf life after opening. Discard any bag that seems hard, cracked, or clumped.

What thin-set mortar is best for shower floor and walls?

Use a polymer-fortified thin-set mortar meeting ANSI A118.4 standards. This provides maximum adhesion and resistance to moisture and mold growth in wet areas. Epoxy mortars offer even greater waterproofing performance.

Can I use leftover thin-set mortar powder for a new project?

Leftover dry mortar can be reused if it hasn’t been mixed with water and is still within its useable shelf life. Always discard any opened bags that have been exposed to moisture or are caked. Unopened mortar lasts longer.

How long should I wait before grouting tiles after installing with thin-set?

Check mortar manufacturer directions, but most thin-set mortars require a 16 to 24 hour curing time before grouting can begin. This allows proper setting and bonding of the tiles. Pre-sealed tiles may take 48 hours.

Can I install tile over vinyl flooring using thin-set mortar?

No, adhesive mortars do not bond well with vinyl floors or sheet goods. Remove old vinyl completely from the substrate before attempting to bond new tiles. Use a crack isolation membrane if concerned about existing cracks transferring through.


Choosing the optimal tile adhesive mortar takes careful consideration of your specific tile material, substrate, environment, performance needs, and manufacturer options. Invest in a quality mortar designed for your particular tile installation. This will help ensure a durable, long lasting end result. Don’t cut corners on this important bonding component. Be sure to follow all directions and preparation recommendations from the manufacturer of your selected mortar. With the right choice and proper application, your tile project will turn out perfectly adhered for years of lasting beauty.