Today I came across an interesting question from a girl on Facebook. She's looking for a master to redo her outdoor terrace.

The tiles need to be replaced. I got into a dispute with one of the commenters.

The essence of the dispute is that I assert that tiles cannot be laid on concrete without proper preparation and waterproofing.

The commenter claims that a penetrating primer is sufficient.

From this, I decided to dive deeper into studying the question of how to do it correctly according to technology. Below I'll provide links to official recommendations from various manufacturers.

Link to the official document.

https://www.murexin.at/app/uploads/Folder_Terrassenaufbauten_EN_2023.pdf

Next, let's go through two more manufacturers. The main requirements are:

1. A slope for free water drainage in the form of precipitation. A fairly steep slope of approximately 20 mm per meter.

2. EN 14891 — waterproofing under the tiles

3. Adjacent areas and corners are sealed separately

4. Outdoor adhesive — deformable C2TES1 / C2S1 according to EN 12004

5. Enhanced cement grout CG2 Epoxy grout RG

I provide links to two other authoritative manufacturers and their requirements.

https://www.ceresit.uk/support/how-to-tutorials/how-to-tiling/tiling-ground-level-terrace-a-type.html

https://www.mapei.com/it/en/products-and-solutions/solutions/detail/waterproofing-and-installing-ceramic-tiles-on-terraces-and-balconies-by-applying-a-mapeguard-um-35-membrane