Installing outdoor tile follows the same general process as indoor tile, with three critical additions: a slight slope built into the substrate for drainage, movement joints placed at regular intervals to handle temperature swings, and materials rated for exterior and freeze-thaw exposure throughout. Skip any of these three and an otherwise well-installed outdoor tile job can crack, heave, or trap water within a year or two of exposure to the elements.
This guide covers the technical side of exterior tile installation. If you have not chosen a material yet, see our Top Outdoor Tile Options guide first.
Table of Contents
- Choosing Freeze-Thaw Rated Materials
- Tools and Materials You Will Need
- Step 1: Confirm the Substrate Can Handle Exterior Use
- Step 2: Build in Slope for Drainage
- Step 3: Plan Movement Joints
- Step 4: Apply Thinset and Set the Tile
- Step 5: Grout with an Exterior-Rated Product
- Step 6: Seal Where Appropriate
- Common Mistakes to Avoid
Choosing Freeze-Thaw Rated Materials
Not every tile is rated for exterior use. Porcelain with low water absorption, generally below 0.5 percent, is the most reliable choice for freeze-thaw climates, since it resists the cracking that happens when absorbed water freezes and expands inside a more porous tile. Check the manufacturer's specifications for a freeze-thaw or exterior rating before purchasing, regardless of how the tile looks or feels.
Tools and Materials You Will Need
- Exterior-rated, polymer-modified thinset mortar
- Notched trowel
- Elastomeric or urethane sealant, for movement joints
- Backer rod, for movement joint depth
- Level and string line, for establishing slope
- Wet saw rated for exterior tile material
- Exterior-rated, freeze-thaw resistant grout
- Penetrating sealer, if using natural stone
Step 1: Confirm the Substrate Can Handle Exterior Use
Exterior tile needs a substrate built to handle constant weather exposure, typically a concrete slab or an exterior-rated cement backer board over a properly framed and waterproofed deck structure. Confirm the substrate is fully cured, structurally sound, and free of cracks before tiling. Existing cracks in a concrete slab will typically telegraph through the tile above them over time unless addressed with a crack isolation membrane first.
Step 2: Build in Slope for Drainage
Outdoor tile surfaces need a slope of roughly 1/4 inch per foot directing water away from the house and toward an appropriate drainage point. Without this slope, water pools on the surface, which accelerates staining, algae growth, and freeze-thaw damage. This is typically built into the substrate before tile is ever set, so confirm the slope is correct at this stage rather than trying to compensate for it with tile placement later.
Step 3: Plan Movement Joints
Unlike interior tile, exterior installations need movement joints, gaps filled with flexible sealant instead of rigid grout, placed at regular intervals (typically every 8 to 12 feet, and always where the tile meets a different material or structure) to absorb the expansion and contraction that comes with outdoor temperature swings. Skipping movement joints is one of the most common causes of cracked or heaved exterior tile.
Step 4: Apply Thinset and Set the Tile
Use a polymer-modified thinset rated for exterior use, applied with a notched trowel sized to your tile. Back-butter each tile in addition to combing the substrate for maximum coverage, since voids under exterior tile are more likely to trap water and contribute to freeze-thaw cracking than voids in a dry interior installation. Maintain your planned slope as you set each tile, checking regularly with a level.
Step 5: Grout with an Exterior-Rated Product
Use a grout specifically rated for exterior and freeze-thaw exposure. Standard interior grout can absorb water and crack under freeze-thaw cycling in a way exterior-rated products are formulated to resist. Leave your planned movement joints ungrouted at this stage, since they get filled separately with flexible sealant.
Step 6: Seal Where Appropriate
Once grout has cured, fill movement joints with a flexible elastomeric or urethane sealant over a backer rod, which allows the joint to expand and contract without cracking. If you used natural stone, apply a penetrating sealer rated for exterior use, and plan to reapply it more frequently than you would indoors, since exterior surfaces face more consistent moisture and UV exposure.
Common Mistakes to Avoid
- Using interior-rated thinset or grout outdoors, where freeze-thaw cycling will cause it to fail
- Skipping movement joints, leading to cracked or heaved tile after temperature swings
- Installing without adequate slope, causing water to pool on the surface
- Tiling over a cracked slab without a crack isolation membrane
- Choosing a tile without a confirmed freeze-thaw rating for your climate
Still deciding on material? See our Top Outdoor Tile Options guide, or browse more installation guidance on our Installation Blog.
