Patio sub base for porcelain tiles

[Jason123]

Good evening all,

I am currently in the process of swapping out decking for a tiled patio.

I plan on compacting MOT type 1 initially, followed by either:

1. Sand / cement mix and wet lay the tiles like slabs

2. Concrete slab poured, then tile directly onto the slab using suitable outdoor adhesive

Can anyone advise on which might be the best option?

I have tiled an ensuite and bathroom and suspect tiling directly onto a concrete slab might be the closest to my previous experience. If I did go this route, do I need to use a decoupling mat or tile straight onto the slab itself?

The tiles are 20mm porcelain. The Internet standard seems to be wet laying, but I have seen a few videos of guys laying straight onto a slab and I can't find much in the way of comparison.

Thank you in advance!

 

[Phone-a-tiler]

If you pour the slab correctly with falls and no dips etc you can direct stick. Use an adhesive suitable for green concrete. Where I work, reo would be used in the concrete to minimise cracking

 

[Lunner]

Wet lay on sand and cement every time, the key is to well compact the type 1, thin layer with a petrol wacker, damping it down will help it to bind together if very dry.

Aim for approx 30mm bed, mix sand and cement to a 1:4 mix with sharp sand, mix it tacky, spread it out to approx the right level, fluff it up with your fingers and tap down to level wth a rubber mallet. Use a string line accross the patio, pack it up on a couple of strips of ply, and use one to check back to the slab/tile you are tapping down.

IMO, from a groundorks background, you woudl ahve a hard time, especially if you aren't used to it, laying a concrete slab to the tollerances need to make the slabs look good

 

[JS1]

Hi I've just been through this exercise using 20mm porcelain 1200mm x 600mm to create a 7.2m x 4.2m patio. I’m a competent DIYer with some limited tiling experience. The Home - https://www.pavingexpert.com/ site is excellent and given the expense and effort I paid for a telephone consultation with Tony McCormack - money well spent. I wasn't confident that I could achieve the perfectly flat finish I wanted using mortar on type 1 etc and opted for laying the porcelain on a concrete slab and fixed with tile adhesive, I used Kerakoll products - isolator membrane, H40 adhesive and grout the Kerakoll rep was very helpful and were Pro Tiler Tools | We Sell a Large Variety of Tiling Tools, Tile Tool, Tools for Tiling, Ceramic Tiling Tool - https://www.protilertools.co.uk/

The slab was laid with a 1:100 fall and I used a Premtool levelling system. The finished result is fantastic. Please message with any questions.