How To Lay Outdoor Tiles On Cement

Before laying any outdoor tiles, understanding your substrate is one of the most important decisions you will make. The method you use, the materials you need and even whether you can grout your patio all depend on what you are laying onto.

The 20mm thickness of our outdoor porcelain tiles is what allows for multiple laying methods, and in this guide we show you how to lay on a concrete screed with step by step instructions.

Fixing outdoor porcelain tiles in the traditional method of laying with adhesive over a concrete screed is ideal for heavy traffic outdoor areas or driveways. This permanent and durable installation method is suitable for both domestic and commercial locations, and because it offers excellent resistance to dynamic and concentrated loads, it can also be used in areas suitable for vehicles such as garage entrances, car parks and yards.

Before laying begins, the concrete substrate must be clean, dry and free from debris. A minimum sub-base of 50mm concrete is required, and it must be of suitable strength having cured for at least 4 weeks (28 days) before tiling commences. Where required, the substrate may need priming beforehand.

If the concrete area is next to a house or property, it must sit 150mm below the damp proof course of the building. A fall ratio of 1:80 should be incorporated across the surface to allow water to drain away effectively.

For existing concrete substrates that are worn or uneven, an external levelling compound should be applied to the base to provide a smooth, clean tiling surface. We recommend UltraFloor Level It Renovate for exterior levelling.

To apply UltraFloor Level It Renovate:

1 - Ensure the substrate is clean, dry, stable and free from any contaminants such as grease or surface laitence.

2 - Apply a coat of a suitable acrylic primer diluted according to the manufacturer's instructions. For example, BAL All in One Plus diluted 1:4 with water.

3 - Using a trowel or pump, spread the Level It Renovate compound onto the concrete. The recommended thickness is between 5-20mm.

4 - Ensure the compound is protected from direct sunlight and excessive wind or draughts whilst curing.

5 - Tiling can commence after 4 hours and must be completed within 48 hours of the levelling compound curing. A primer may be required before tiling.

Using the correct adhesive is essential when fitting 20mm outdoor porcelain tiles to ensure the longevity of the installation. A C2 improved cementitious adhesive with either S1 or S2 flexibility must be used, which essentially means a high strength flexible adhesive suitable for large format outdoor tiles.

We recommend BAL Rapid XP Plus, which has a pourable consistency that makes application easier and ensures good coverage across the tile.

Please note that fixing should not be carried out in temperatures below 5°C or in damp conditions.

Due to the size and thickness of our outdoor tiles, edges and corners can lift when pressure is applied to different areas of the tile as it is embedded into the adhesive. Using a levelling system is highly recommended to reduce the chance of lipping and ensure an even finish across the installation.

1 - Using a large format trowel, comb a bed of adhesive directly onto the prepared substrate.

2 - Back butter the reverse of each tile before fixing into the adhesive bed, particularly if not using a pourable adhesive. This ensures 100% adhesive contact evenly across the tile.

3 - A joint width of no less than 5mm is recommended when installing outdoor porcelain tiles.

4 - If expansion joints are required, these should be at least 5mm wide and must flow through the substrate and the tile surface.

5 - Perimeter joints should be left where tiles meet walls and any raised areas. These can be filled with a compressive material such as silicone.

Always ensure the correct PPE is worn at all times when installing outdoor porcelain tiles.

Grouting should be completed using a suitable external grout such as BAL MicroMax3. As a concrete base is not permeable, brush in grouts are not suitable as water will not drain away from the installation. Grouting should not be attempted in temperatures below 5°C or in damp conditions.

For more ways to fit outdoor porcelain tiles, including on gravel, grass and pedestals, take a look at our outdoor tile fitting guides, or for ongoing care advice visit our guide on how to clean outdoor tiles.