Concrete courtyard paving advice and project

johnk

Hi everyone,

I am doing some research on paving my concrete courtyard which is 2.60m by 9.1m with 2 large steps. The concrete is in good shape with very little visible cracking after 22 years and I have painted it twice in that time. It slopes towards one side into a drain square area, and one area does have some steepness to it leading into the drain. There are two formed joints in the concrete.

I have thought about getting synthetic square decking tiles, a pebble/glue mix or even repainting it but would like to pave it property.

400mm x 400mm pavers seem to be a good compromise for the area.

I have never tiled or concreted anything before.

Some questions/complexities I see as follows:

- Should I use rapid set concrete. regular concrete or mortar to attach the pavers to the concrete? I see no need to fill with sand and a different base - will clean and bleach the concrete 

- I gather I will need to pave in 3 separate sections to keep to each area that is subdivided by the joints in the current concrete and use a flexible sealer in between these, as well as cut the tiles to fit each section?

- The area can remain quite moist in winter - as such rather than use the same material to attach the pavers to the concrete as grout, do I need to use a better grout material? This means keeping the spacing between paver clear of concrete when laying them? 

- In terms of maintaining the current slope to the drain, what is the best way to do this? Can guide lines assist here as well? Or do I simply use a spirit leveler and maintain the same angle as the concrete?

- What thickness of concrete/mortar do I need to lay under the pavers? Assume that I get 400mm x 400mm which weigh approximately 14 kg and how do I match this with the trowels I get?

- I don't know if I actually even need pavers? Will outdoor slate type tiles 10mm thick do it? I really like the look of outdoor slate tiles and believe for 24 sm I could be looking at less than $1000 

   

MitchellMc

Welcome to the Bunnings Workshop community @johnk. It's sensational to have you join us, and many thanks for your question about laying pavers.

Typically, you would bed pavers with mortar. That will stop them from moving around to a certain degree, but you are not adhering the paver to concrete; you're trying to stick them to the paint. The paint is a barrier. That's why the mortar will function more as a bedding medium rather than any adhesive.

Have you seen much movement in the expansion joint over the years? Any visible gaps that enlarge and close? It would be ideal to isolate the three portions. However, I think what's going to happen if you get significant movement is cracked grout lines. Repairing the grout line directly above the expansion join now and then might be worth it, considering you won't end up with cut tiles in odd positions.

To establish the slope, I'd suggest following the one already there. You can use a notched trowel to distribute the mortar evenly; if you do so, the pavers will follow the slope. Depending on how harsh the slope is, you might need to cut the paver to suit.

You don't generally grout between pavers; you fill the gaps with sand. It sounds like you might want to tile the area. If so, you'd use a flexible grout suitable for exterior use. If you are tiling, you should use a tiling adhesive instead of mortar. The issue here is that I'm unaware of an adhesive recommended over a painted surface.

If you are using pavers, then the 12mm notched trowel I linked above should be suitable for the bedding mortar.

Using tiles is an option, though I suspect you might need to remove the paint to glue them down.

Please let me know if you have further questions.

Mitchell