How to tile over exposed aggregate?

Hi brainstrust,

Long time observer, first time post. Recently hit a roadblock with our exposed aggegrate patio and am getting very confusing advice from various trades.

Long story short, we moved into this property with a large concrete area however the exposed agg must be quite worn as it was very sharp to walk on and my kids would cut themselves badly if they tripped. We had it honed back but unfortunately it came up very patchy and we were told it was due to the age of the concrete and the high ratio of rocks vs cement (see images). Sadly with that money down the drain we need to find another option to resurface it. We're considering tiling it but after seeing the labour costs we are mulling the idea of DIY. It's a large area (65sqm plus the rear pathway) but it is relatively flat I believe and square-ish, and has already been grinded back i.e. any previous sealant has been removed, which I understand is necessary if adhesive is applied for tiling.

The concrete I believe is over 8-10 years old. There is one big crack in the rear pathway but small fractures in the main alfresco area. Relatively flat in most areas after going over with a spirit level.

Questions:

1) I'm generally handy and have done floorboards in the past (and maybe 15yrs younger), are we insane to consider to take this on as a first time DIY tiling project?

2) Confirming that it is okay to tile right over the exposed aggregate with suitable adhesive mix?

3) Are 10mm thickness tiles strong enough to apply? Noting not all the exposed aggregate is completely flat (see images)

4) Considering 600x600 tiles, what pattern should they be laid and which corner do you start from?

5) I went into Bunnings and was told all their tiles are not suitable for outdoors, is this correct? Referring to the Duratile 600x600s.

6) What do I put on the edges to finish? Metal strips?

Thanks in advance for any advice!

Cheers,

Wei

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Comments

JacobZ

Hi @Wei123,

Welcome to the Bunnings Workshop community, it is fantastic to have you with us.

I don't think you are crazy to take on this kind of project, although it is quite large. Tiling itself is not that hard; if you do the prep work, carefully lay things out to set yourself up for success, you should be able to produce a great result.

Yes, you can tile over this concrete, but it would be best to get the surface perfectly level before tiling. You can account for slight unevenness in the slab by using a thicker bed of adhesive, but this can cause the adhesive to dry unevenly which can weaken it. Any cracking in the adhesive can cause movement and eventually cracking in tiles, especially when using thinner tiles such as the 10mm tiles you mentioned. For these reasons, I would consider using a self-levelling compound that is suitable for outdoor applications such as Dunlop Ardit Floor Leveller prior to tiling.

If you used a thicker tile, more along the lines of a paver, you could get away with using a bed of mortar, without any additional levelling.

Generally speaking, you should lay out your tiles based on the points where the eye is drawn and foot traffic is high. In your case, everything should likely work off the door and the line of the wall that it sits in. Try to space things so that any cut tiles on either side of the space are relatively even. Snapping lines with a chalk line and dry laying your tiles before they are attached will help with visualising the area. For changes in direction, like the pathway down the side of the house, adding a strip of different, smaller tiles to create a breaker strip will allow you to adjust the layout to suit the change in direction.

For an outdoor space like this, you need to use outdoor-rated tiles like these Johnson 300 x 600mm Grey Hampton Outdoor Porcelain Floor Tiles. They have a gritty surface and are tested and given a slip rating. There are only limited options for outdoor tiles kept in stock. Our friends at Beaumont Tiles have a wider range of Outdoor Tiles. It would be worth checking out their range for more options.

For the edges, tile trims are the way to go. Something like this QEP 10mm x 3.0m Silver L Shaped Tile Trim Angle might be a good option for you.

Allow me to tag @EleventhCoastal, @Nailbag and @TedBear to see if they have any advice or guidance they can offer.

Let me know what you think and if you have any further questions, please don't hesitate to ask.

Jacob

TedBear

https://www.workshop.bunnings.com.au/discussion/comment/55966#Comment_55966

Thanks for the Tag @JacobZ. I don't have any advice to offer, because I have a similar problem myself, so I will follow up on your suggestions and watch out for anything that the other contributors may have to offer.

Nailbag

Hi @Wei123 see below:

Questions:

1) I'm generally handy and have done floorboards in the past (and maybe 15yrs younger), are we insane to consider to take this on as a first time DIY tiling project?

A: DIY vs the cost of professional done is significant to say the least. If you're handy and prepared to take your time your starting off an exceptionally good base. I would say go for it.

2) Confirming that it is okay to tile right over the exposed aggregate with suitable adhesive mix?

A: Unless proven wrong, I would say yes. It's important to use a flexible adhesive and obviously follow the directions of the manufacturer. But personally I would consider the base you have to work from is an excellent one and instead lay pavers on a washed white sand base. This would be significantly cheaper and easier to lay.

3) Are 10mm thickness tiles strong enough to apply? Noting not all the exposed aggregate is completely flat (see images)

A: I wouldn't, as you're lending yourself to cracked tiles and grout. I would be surprised if suitable external 10mm tiles are even available.

4) Considering 600x600 tiles, what pattern should they be laid and which corner do you start from?

A: I would go with 450 x 450 max as being much easier to manage as well as a multiple of other reasons. use the house as your straight line reference and start at one corner wall to work along.

5) I went into Bunnings and was told all their tiles are not suitable for outdoors, is this correct? Referring to the Duratile 600x600s.

A: That is correct

Screenshot 2025-08-16 at 9.22.22 pm.png

6) What do I put on the edges to finish? Metal strips?

A: Mortar bed or steel edging would be thew best long term.

Nailbag

Wei123

https://www.workshop.bunnings.com.au/discussion/comment/55966#Comment_55966

Thank you @JacobZ and @Nailbag appreicate the advice.

I think I'm leaning towards tiling but haven't ruled out completely the paving. Went to Beaumont tiles who recommended some outdoor tiles. Assuming I go for the tiling option, perhaps my highest uncertainty is the levelling prep stage. I feel fairly comfortable to give the laying of tiling a go but agree that the prep would need to be done well.

With levelling, there seems to be a fair few YouTube videos on the use of the material for indoors where there are defined walls, but not outdoors. Some questions to go with this:

1) When levelling, should I be avoiding lettting it seep through the expansion joints? If so, how do I go about this?

2) Similiar to the first question, how do I ensure I avoid the edges as I can see there is some residual expansion joints connecting the walls of the house.

3) How do I not let the levelling material pour too much onto the grass on the outer edges? Do I build some kind of form work beforehand? If so, what is the best material to use without it sticking to the self leveller?

4) How do I protect the limestone around the bbq area from any splashes from the self leveller or is it easy to clean off any mistakes made?

Protecting expansion joints?Formwork required to avoid excess leveller running off into grass?Protecting expansion joints?How to protect limestone

Thanks again in advance, super helpful.

Wei

Nailbag

https://www.workshop.bunnings.com.au/discussion/comment/90427#Comment_90427

Hi @Wei123

1) When levelling, should I be avoiding lettting it seep through the expansion joints? If so, how do I go about this?

If you tile, then you will be using some form of recommended adhesive, so I would use a flexible filler like Sika 11FC.

2) Similar to the first question, how do I ensure I avoid the edges as I can see there is some residual expansion joints connecting the walls of the house.

Leave a few mm gap between the house and tile edge. This can be filled with either the same Sika product.

I wouldn't use self-levelling compound at all. You want the tiles to have a gently fall away from the house which can be achieved with the tile adhesive. But if there are substantial dips runnings length-wise just use timber against the edge of the pebblecrete path. Just be away that levelling compound has a max depth limitation which various between product/brand. But I would only use in an extreme case and simply stick to the adhesive if possible.

4) How do I protect the limestone around the bbq area from any splashes from the self leveller or is it easy to clean off any mistakes made

You usually just gently pour self-leveller out of a deep bucket. But of your concerned you could use this self-adhesive drop sheet roll. It might just need to some help sticking to the lime stone with say gaffe-tape which sticks to anything..

Nailbag

MitchellMc

https://www.workshop.bunnings.com.au/discussion/comment/111093#Comment_111093

Hi @Wei123,

As @Nailbag mentioned, it's best not to apply self-leveller over the whole area as you'll level it, whereas it should be graded away from the house, and the slab is likely already sloped. However, you can use the self-leveller to fill deep depressions, if needed.

They've answered most of your questions, but please let us know if you have anything further.

Mitchell

Wei123

https://www.workshop.bunnings.com.au/discussion/comment/122941#Comment_122941

Thank you @Nailbag and @MitchellMc for the advice.

I think I have misunderstood Jacob's initial advice with using the leveller that he recommended, and applying to the whole area. We've had recent storms in Perth with sideways rain and it's presented some obvious low areas where it has pooled. I imagine I then apply the recommended product to these areas? Essentially I should be spot levelling the area is what I'm hearing.

Can I please be recommended a flexible adhesive suitable for exposed aggregate? By using a flexible adhesive, could this increase the risk of tile cracking? Just wondering how flexible we are talking. Sorry if that's a dumb question!

Cheers

Wei

EricL

https://www.workshop.bunnings.com.au/discussion/comment/130705#Comment_130705

Hello @Wei123

Just to clarify you are referring to a tile adhesive, yes? If you are, I suggest looking at the Dunlop 20kg Trade Resaflex. It is a rubber modified tile adhesive and is rated for indoor and outdoor use. Using a flexible adhesive is actually better as it can withstand movement from the substrate to a certain degree which will prevent the tiles from cracking. The same can't be said if you were to use nonflexible tile adhesive. Resaflex allows for minimal movement and is suitable for situations where only slight movement is anticipated, such as over stable substrates like concrete, render, or fibre-cement sheets, not timber floors.

If you need further assistance, please let us know.

Eric

Nailbag

https://www.workshop.bunnings.com.au/discussion/comment/130705#Comment_130705

Hi @Wei123

That product @EricL has linked looks to be ideal for your project. However, like all adhesives it's very important that you follow the guidelines outlined by the manufacturer. In this case the "Application" instructions in the documents file with particular attention to these points:

Use a 10 x 10 x 10mm trowel on floors.
Do not apply DUNLOP TRADE RESAFLEX at a bed thickness greater than 6mm or less than 1.5mm.
Press and slide the tile at right angles to the notch pattern to ensure 100% coverage on the back of the tile. Do not butt-joint tiles.
Deeply keyed quarry tiles and some extruded tiles may require buttering of the adhesive on the back of the tiles to ensure 100% coverage.

Nailbag

Wei123

https://www.workshop.bunnings.com.au/discussion/comment/135479#Comment_135479

Thank you @Nailbag and @EricL

Appreciate the recommendation. Not sure if you can see from the photos but on the exposed aggregrate the rocks are quite high compared to the cement level i.e. well exposed to the point where I would say some areas would be greater than 6mm depth. This would mean the adhesive material would be thicker than this when applied. This being the case, I feel perhaps the leveller needs to be applied across most of the area where it is not flushed, and use a thinner layer of the leveller, or, use an alternative adhesive that allows for a thicker bed?

I note from a previous post of yours @EricL that you recommended:

https://www.bunnings.com.au/davco-20kg-ultraflex-ceramic-tile-adhesive_p6656384

Would this be a more suitable alternative? Cheers.

Thanks again.

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/138708#Comment_138708

Hi @Wei123,

The problem with using just tile adhesive to account for changes in height is that you won't get even coverage underneath the tiles. Once the tiles are pressed into place, the adhesive will spread out, so you might have 4mm of tile adhesive under one part of the tile and 12mm under another part, which really isn't great practice.

Assuming you are using ceramic tiles, either the Dunlop Resaflex or Davco Ultraflex would work as long as you follow their instructions closely, but you shouldn't rely on a thicker bed being the solution to the gaps between the aggregate.

You would be far better off using the self-levelling compound to smooth out the differences in height, then set your tiles in place over the top of the levelling compound using a suitable adhesive for your tiles. As @MitchellMc mentioned, you should use it to pour through the depressions caused by the exposed aggregate, but don't cover the whole patio as it will level and take away any slope from the concrete.

In my initial post, I should have said "flat" as opposed to "level". Apologies for that.

Let me know if you have any further questions, I am happy to help if required.

Jacob

Wei123

https://www.workshop.bunnings.com.au/discussion/comment/140847#Comment_140847

Thanks @JacobZ

I had a closer look at the Davco Ultraflex, and it recommends 12mm max for tiles greater than 400x400. Would I then apply 6mm on the ground and 6mm on the tile?

The Davco Ultraflex recommends putting a primer down first, is this necessary? If so, could you please recommend a suitable primer for my exposed aggregrate? Thanks.

Prior to applying leveller in select areas, would a primer still be required before applying leveller?

Cheers,

Wei

EricL

https://www.workshop.bunnings.com.au/discussion/comment/142432#Comment_142432

Hello @Wei123

The instructions for back buttering were very general, but it did mention to apply a thin covering only. It would be best that the majority of the adhesive be applied to surface rather than the tile. Remember to follow the installations instructions especially how the tile needs to be moved into position.

I propose using the Lanko 1L Ultraprime 124 Surface Primer as this primer can be used with self-levelling products as well. This primer would need to be applied to the area where you'll be using the leveller.

If you need further assistance, please let us know.

Eric

Wei123

https://www.workshop.bunnings.com.au/discussion/comment/143564#Comment_143564

Hi @EricL - Thank you for that. Would you mind also recommending a grout? Is there only one type or should there be a particular grout that has flexibility too like the adhesive?

@JacobZ - regarding your suggestion, "For changes in direction, like the pathway down the side of the house, adding a strip of different, smaller tiles to create a breaker strip will allow you to adjust the layout to suit the change in direction." - do you have an example of what this looks like?

Thanks all!

JacobZ

https://www.workshop.bunnings.com.au/discussion/comment/144428#Comment_144428

Hi @Wei123,

I couldn't find a great example so I used AI to generate something. It's a little bit wonky, but it shows the general idea.

The idea is that by adding a breaker strip, you can transition from one layout to a different one. With the breaker strip separating the tiles, it would not be such a big deal if the tiles were misaligned slightly from the patio to the pathway.

For grout, I'd suggest using Davco Sanitized® Colourgrout in a colour of your choosing. To increase the flexibilty, you can add Davco 1L 4 In 1 Grout Additive to your grout mix.

Let me know if you have any further questions.

Jacob

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