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
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.
thanks for the comments:
"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."
The answer here is no. So what does that mean? I don't follow your response. If I do this in three sections and add a flexible sealer in between above the expansion joints why would I get cracked grout lines? Or are you suggesting that this will only happen if I don't do this and that I should not worry about it?
"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 I want to tile then, I gather that I will need to remove the paint. This will need too much work.
Why wouldn't a rapid set concrete or mortar allow me to attach tiles to the painted concrete floor? The flexible grout then sits over this does it not?
I guess at worst case scenario I will hire a concrete floor grinder and grind away for a day. Could be the safest option!
If you did it in three separate sections, then you shouldn't have any issues. Since you're not seeing any movement, you could potentially just pave over the whole area instead of doing three sections.
You'll be using an adhesive to stick the tiles to the concrete and then a flexible grout between them.
A cement-based adhesive works best applied over a porous and textured medium. The paint isn't porous, and it's too smooth. It's not that the adhesive wouldn't adhere at all; it's just our supplier can't guarantee their product over your painted surface. You'd need to apply Davco Ultrabond, which is a two-part primer, to the paint before you can use an adhesive on it.
Ok so that I have this right. It sounds like the easiest option is:
1. Clean and pressure wash area
2. Apply Davco Ultrabond two-part primer to the painted concrete
3. Apply tiles with an adhesive to stick the tiles to the concrete
4. Grout tile
Can you suggest an outdoor flexible grout for the tiles?
Also for the steps, I have seen guards or stainless steel or aluminium rails that are used at the end of the steps to create a rounded edge and protect the tiles from breaking. Any recommendations?
Please let me know if you have further questions.