How to increase concrete height of patio?

emmaqld22

Hello, 

I'm currently tiling my pool / outdoor area with a 20mm outdoor p4 tile to match the coping. For the patio / undercover area I’d like to swap to a different (cheaper) 10mm tile. I’d like to achieve a level transition between the two tiles. To do this I’ll need to bring the patio up 10mm to accommodate the difference in tile thickness. I have some questions about this: 

- Is a self levelling product the best option for this? What product is recommended under tile & outside? 
- The slab has had some expansion joints cut into it. How does the levelling product work with the expansion joints ? Do I fill them with some sort barrier & pull out when dry? 

Thank you 🙂 

EricL

Hello @emmaqld22 

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about your patio flooring.

A self-levelling compound can be used to raise your slab by 10mm, but it must be suitable for external applications and under-tile use. Many standard self-levelling products are designed for internal applications only, so you’ll need to choose a product specifically rated for outdoor environments, offering water resistance, UV stability, and compatibility with tile adhesives. Application will need to be done properly as any inconsistencies will show up as you apply the tile on its surface. You'll need to give the self-levelling compound time to cure properly before tiling. 

The only levelling compound I'm aware of that meets all the requirements is the Lanko 20kg 173 Floor Leveller.

When it comes to expansion joints, things do become a bit more intricate. You’ll need to temporarily install a compressible barrier while applying the self-levelling compound, making sure under no circumstances it flows into or bonds across the joint. Once the levelling compound has cured, that barrier will need to be removed, and an appropriate expansion joint system integrated into your tile layout.

It’s also essential that all nearby materials such as tile adhesives, grout, and sealants are flexible or designed to accommodate movement. These steps ensure the integrity of your tiled surface over time, but they do require careful planning and the use of specific tiling components.

All in all, it’s a fairly involved process. If it feels like it might be pushing the limits of your D.I.Y. comfort zone, it might be worth getting a quote from a concreting or tiling professional. Even just a consultation can help you weigh up your options and see if it still fits within your budget.

Let me call on our experienced members @Dave-1 and @Nailbag for their recommendations.

If you have any other questions we can help with, please let us know.

Eric