How to tile an outdoor porch with a cracked slab?

[cococat]

Hello 

i would like to tile/pave my porch. At the moment there is a concrete slab with expansion joints in place as shown. The slab has dipped towards the step and cracked so is not level.
Would you dig up the porch and redo a slab, use a concrete levelling product over the existing or just tile over? 

Thank you for your assistance- much appreciated 😃

 

[Jewelleryrescue]

Hi @cococat 

The real  dilemma is has the concrete stopped moving?  Lets assume it has for now.

 The lean of the concrete is towards the outside  and not to bad you the natural slight fall will redirect rain away from the doorway if  tiled over is a plus. So  you can tile directly,

Alternatly  prop timbers to the outside of the slab and fill the  inside  with self leveling cement. and tile over the top once it is cured. 

Ideally a slight fall to the step created when tiling will naturally shed water way.

[MitchellMc]

Welcome to the Bunnings Workshop community @cococat. It's terrific to have you join us, and many thanks for your question about paving a slab.

An unstable slab or one with expansion joints is not a great base for tiling over. Both of those issues will cause your tile grouting or tiles to crack. In order to pave a slab, it needs to be stable, so it sounds like you might need to consider repouring a new slab. A self-leveller is also unsuitable as it can't be used over expansion joints or an unstable surface; it will just crack.

Here's a helpful guide: How to pour a concrete slab.

Please let me know if you have any questions.

Mitchell
 

[cococat]

Thank you for your recommendations- yes I am concerned about the slab moving so may have to redo it all! 

[cococat]

Thank you MitchellMc for your advice. Yes it looks like the existing slab will have to come up!

if I did this could I lay bluestone pavers on a bed of sand instead of pouring a slab?

Thanks again!

[MitchellMc]

That certainly sounds like an option, @cococat. I would advise that you hire a compactor and run over the area quickly to ensure you have a solid and compact substrate for your pavers.

Mitchell

[cococat]

Thank you- will consider this option as it may be easier for me!