How to build crazy paved alfresco tiled floor?

Bobg

This is the current draft of the Alfresco area that we are planning. The large recycled timber table will be the centre piece.

My concern is as follows.

1. The existing alfresco area is sunken between 35 to 40 mm. It use to have a timber deck that we removed as the timber began to splinter and cause issues
2. The tile edging and crazy pave will be 20 mm thick. This does not leave much depth for the concrete base to place the tiles onto.
3. Is this sufficient depth to lay these tiles/pavers or are they likey to crack and dislodge.
4. Is a concrete base the right way, or is there an adhesive that is a better option.
5. I can use thicker tiles if necessary as i suspect 15-20 mm adhesive is also not the best

Any assistance on how to make this happen would be appreciated

MitchellMc

Hi @Bobg,

The 35–40mm available depth is going to be the main challenge. If your stone is already around 20mm thick, that leaves only 15–20mm to accommodate everything underneath it. That's not enough room to pour what I would consider a meaningful new concrete slab or topping and then bed the stone over it.

If there is already a sound concrete slab beneath the area, however, you shouldn't need to add another concrete base. The existing slab can potentially become your substrate, with the stone installed directly over it using an appropriate exterior-rated stone/tile adhesive. In that situation, the 35–40mm recess could actually work quite well with 20mm stone, as the adhesive bed would only need to make up the remaining height rather than being 15–20mm thick throughout.

I'd first remove any remaining decking components and thoroughly assess the existing substrate. Check that it's solid, reasonably level, free from significant cracking and has adequate fall for water to drain away rather than towards the house. You can then determine exactly how much height you have at the highest and lowest points.

If the underlying surface isn't suitable and you need to create a new structural concrete base within that 35–40mm depth, I'd be hesitant to proceed with the current design. A very thin layer of concrete isn't going to perform like a properly constructed slab, and cracking or movement underneath could transfer through to your paving.

I also wouldn't select thicker stone to solve the problem. That would leave you with even less room to prepare and correct the substrate. Your proposed 20mm stone over an existing sound concrete slab would be the direction I'd investigate first.

It looks like it will be a spectacular alfresco area once completed. The crazy paving and darker border should work beautifully with that recycled timber table.

Let me tag @manisha.nair, @AdamCook_93, @LD44 and @genw, who have all completed some wonderful alfresco areas recently, to see if they have any thoughts.

Please let me know if you have any questions.

Mitchell