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Quick Answer
Yes, you can install outdoor tiles over an existing concrete patio or walkway. The key is properly preparing the concrete surface and using the right types of tile and installation materials to ensure a long-lasting result.
What is Required to Install Outdoor Tiles on Concrete?
Installing outdoor tiles over concrete requires a few key steps and materials:
- Clean the concrete surface – Remove any dirt, debris, grease or existing coatings
- Repair any cracks or damage – Use concrete patch compound to fill cracks and holes
- Roughen the surface – Use a concrete sander, grinder or acid etch to roughen and open pores for better adhesion
- Apply a tile Primer – Primer improves adhesion of the mortar
- Mortar – Use a polymer-modified thinset outdoor mortar designed for large tiles
- Outdoor floor tiles – Choose a tile rated for outdoor use like porcelain, natural stone or cement
- Grout – Use a sanded polymer grout designed for joints 1/8” or larger
- Sealant – Seal perimeter joints between the tile and other surfaces
Proper surface prep, mortar and tile selection are key elements to a long lasting outdoor tile installation on concrete.
How to Prepare Concrete for Outdoor Tiles
Preparing the concrete surface is one of the most important steps when tiling over existing concrete. Here are some tips:
Clean and Remove Any Existing Coatings
The concrete must be thoroughly cleaned before tiling. Sweep away dirt and debris, then use a concrete degreaser to remove any oil or grease spots. If the concrete was previously painted or sealed, these coatings need to be completely removed by scraping, grinding or using chemical strippers. The tile mortar will not adhere properly to an uneven or sealed surface.
Repair Cracks and Holes
Check the concrete for any cracks, chips or holes and fill these using a concrete crack filler or patching compound. Allow any repairs to fully cure before tiling. Unrepaired cracks are prone to telegraphing up through the tile.
Roughen the Surface
This is the most important step for adhesion. The surface of cured concrete is very smooth and dense and will not bond well with the mortar unless it is roughened. This can be achieved by:
- Acid etching – Using muriatic acid solution to open pores in the concrete
- Grinding – Using a diamond blade grinder or sander to abrade the surface
- Shot blasting – Blasting the surface with abrasive media at high pressure
After roughening, sweep and vacuum up all debris and dust.
Apply Primer
After cleaning and roughening, apply a cementitious primer to further improve adhesion. Roll or brush on an even layer following the product directions. Let the primer fully cure before applying mortar.
Choosing Outdoor Tiles for Concrete
The type of tile used is critical for outdoor installations on concrete. Choose tiles with these features:
Outdoor Rating
Only use tiles rated for exterior use. Outdoor tiles are designed to withstand weather, temperature changes and UV exposure without fading or damage.
Moisture Resistance
The tile must have very low water absorption, below 3% or less. Porcelain, natural stone and cement tiles have excellent water resistance.
Durable Surface
Textured tile surfaces perform better outdoors compared to very smooth glazed surfaces which can become slippery when wet. A honed, tumbled or natural stone finish provides grip.
High Strength
Outdoor tiles need to be durable and resistant to cracks and chips. Stone and porcelain strengths range from 15,000-40,000 psi.
Popular outdoor tile options include:
- Porcelain
- Natural stone – granite, slate, travertine, limestone
- Cement tile
- Mosaics
Avoid glass tiles or ceramic tiles without an exterior rating.
Choosing the Right Mortar and Grout
Outdoor tile projects require specialized setting materials:
Tile Mortar
A polymer-modified thinset designed for exterior applications should be used. Standard thinsets lack the adhesion strength and flexibility needed outdoors.
Grout
Choose an unsanded or sanded polymer grout. Standard cement grout will deteriorate outdoors. Polymer grout is more durable and stain resistant.
Sealants
Use a flexible polyurethane sealant to fill expansion joints between the tiled surface and adjacent walls, steps, borders, etc. This prevents water intrusion under the tile.
With the right mortar, grout and sealant products, the tile installation will withstand weather, temperature changes and normal movement without cracking.
Step-by-Step Installation Process
Once the surface prep is complete and materials selected, the tile can be installed. Here is an overview of the process:
Step 1 – Apply Mortar
Use a notched trowel to spread a layer of thinset mortar over the primed concrete substrate. Spread only as much as can be tiled before the mortar skins over.
Step 2 – Set the Tiles
Firmly press the tiles into the mortar. Use spacers for consistent grout line width. Check for full mortar coverage under tiles periodically by lifting a few.
Step 3 – Grout the Tiles
After the mortar has cured per the product directions, mix the grout and apply it over the tile using a rubber grout float. Push it fully into joints and let it firm up slightly before cleaning the excess grout haze.
Step 4 – Seal the Perimeter
Once the grout has cured, use a sealant along all joints between the new tile surface and adjacent areas. This seals the installation from moisture.
Avoid foot traffic on the tiles for at least 24 hours. Wait 72 hours before grouting or sealing. Allow light foot traffic only after 7 days for the mortar to fully reach strength.
Tips for Successful Installation
Follow these tips for a long lasting tile installation over concrete:
- Use the right mortar – polymer-modified thinset with high bond strength
- Allow concrete repairs to fully cure before tiling – at least 28 days
- Roughen concrete to a CSP 2-3 profile for proper bonding
- Use outdoor-rated grout and sealants
- Avoid cracked, damaged or low strength concrete
- Install expansion joints if concrete is prone to movement or cracking
- Ensure proper slope for drainage – minimum 1/4″ per foot
Proper prep work is vital – trying to save time or money here can result in major problems down the road. Investing in the right materials also prevents issues.
Outdoor Tile Maintenance
Like any surface, outdoor tiles will require periodic maintenance to keep them looking their best:
- Sweep or rinse regularly to prevent dirt buildup
- Clean stains and spills quickly to prevent absorption
- Re-apply sealers every 1-2 years to protect grout and tiles
- Watch for cracked, loose or damaged tiles and repair immediately
- Inspect grout lines and re-grout if needed
- Pressure wash annually to deep clean and unclog pores
With proper installation materials and routine care, outdoor tiles can remain in good condition for many years even in harsh climates.
Conclusion
Installing tile over exterior concrete is a great way to add aesthetic appeal while still enjoying the low maintenance benefit of a concrete patio or walkway. With proper surface preparation, correct product selection, and professional installation, you can achieve beautiful, long-lasting results. Paying close attention to details like proper slope and drainage, expansion joints, and routine maintenance will help the tiles last for decades of outdoor enjoyment.
| Surface Prep Steps | Materials Needed |
|---|---|
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| Tile Type | Features |
|---|---|
| Porcelain |
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| Natural Stone |
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| Cement Tile |
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