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How to lay paving on top of concrete slab?

We are planning to lay crazy paving on top of our existing concrete slab. I've read about a couple of different methods including using sand as a base or using mortar. We also want to raise the height up by almost 10cm.Taking into consideration the paver thickness, can we layer mortar directly onto the concrete slab to our desired height or should we be doing something different to increase the height and then adding a 10-15mm later of mortar before the pavers? Any suggestions or tips much appreciated.

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Jewelleryrescue

Hi @rachelh28

Great project you are doing/ 🙂

Guide :

- Cement mortar ideally need s to be 20mm thick at its shallowest so it has some strength. So your thickness of 10cm minus paver thickness (50mm?) will give you a strong 50mm or so mortor thickness this is great.

- Yes you most definatly can lay mortar on top of a clean concrete slab in fact thats great as you will have a flat surface to work on.

- Garden pathes never have to be dead flat or dead straight in fact I deliberaly curve all mine if possible and put a slight tilt to run rain water off them.

Hi @rachelh28

Wet cement OR you can do this with no water it is much easier. Still using dry (Sand and cement ) pre mix later you will water the path starting the cement setting.

Path thickness = 100mm (you wanted) - Paver thickness eg 50mm equals cement thickness of 50mm. Note when you lay cement add 5mm so 50 mm is now 55 mm this is to allow the crazy path to be tapped down into the cement making good contact.

Your path make wet mortar (premixed sand and water at bunnings) mix it with water pour it on the start point of your path so its ( tooth paste like smoothness) . Start pouring it out wet mortar or add dry mix on old path and spreading it out to 55mm thick( come down the path 1 meter at @55mm thick and flat Now gently lay the crazy pave on top of wet or dry cement. Move it into position and tap with hammer a 1 meter long wood (35x 75mm approx timber)across the top of the crazy pave so it gently pounds the crazy paver down to 50mm and level as you want.

Tip the leveling timber is like icing a cake if you see any lumpy bits put on the timber and tap it level with all the other stones. If you have a low bit lift the crazy pave up and put more morter under or dry sand and cement. Now its level/ Slide the timber down over the newly laid crazy pave and tap it down to you desired path height.

Tip itsa good idea to have path thick ness markers along the sides of the path so you know if your work is too high or low, so you can adjust.

Puttin pavers on dry sand and cement mix is the easiest way as no hard work to mix it up in a wheel barrow etc. plus you can take your time to add or subtract mixture to get the perfect path/ . Once the path is laid you can even add sand and cement powder between the pavers and then with a hose saturate the path full with plenty of water with a slow flowing hose (so mixture not hosed out at all) Start the hose flowing at hill end of path it will flow down hill and into the sand cement mixture. This will clean paving surface at the same time. Move the hose at need we dont want so much water mixture starts flowing out like muddy water.

Have you hear of cuflue the thin 5mm plastic board signs are made of . I would by a bunnings 5 mm sheet (roll it up for car) and cut it into path edging strips eg 100mm each side your desired path thickness use some pegs to hold it in place now you have a path with channels on the outside and it will be the same level of the top of your path as a guide and no sand and cement will spill or push out from under the path while setting.

Well I wrote a book hope this helps.

EricL

Hello @rachelh28

Welcome to the Bunnings Workshop community. It's sensational to have you join us, and thanks for sharing your question about crazy paving.

It's great that you've received excellent advice from @Jewelleryrescue.

I just wanted to be sure that you need to increase your concrete base to 10cm taking into account the thickness of your pavers. Before I make any suggestions, can you please tell us how thick are the pavers you'll be using? Can you also please tell us how big is the area you'll be tiling? If the area you'll be doing is quite large, I would suggest adding the concrete first to increase your concrete base height. You can then make sure that the added concrete will be flat and level.

Once the added concrete cures, it will now be much simpler to layout the pavers and you are not rushed to complete the task. If the pavers you'll be using are all at the same height, then you'll have a nice level finish. Once you have the pavers in the configuration you like, you can then apply the adhesive and stick the pavers to the concrete base. Once the adhesive cures, the last step will be to grout the pavers.

I suggest having a look at this featured discussion - Crazy paving front porch by @EleventhCoastal.

Let me call on our experienced members @Nailbag and @Dave-1 for their recommendations.

If you need further assistance, please let us know.

Eric

Dave-1

https://www.workshop.bunnings.com.au/discussion/comment/44111#Comment_44111

Good morning @rachelh28

I would be using mortar to secure and to raise the 15ish mm in height that you want. Going through the response I am thinking aphoto of the area would be good to see as if its a large area then the way to do may change as @EricL has suggested. I have really come to like the crazy pave style ashave seen some nice projects in here. Please take a bunch of photos, well lots as you go and consider putting it up here as a project 🙂

What sort of stone are you thinking of using btw? Just as a matter of interest more then anything.

Dave

Nailbag

Hio @rachelh28

I have done this project a few times now and I would be essentially following the method of wet or dry sand & cement base @Jewelleryrescue has explained. In the projects I have done, it's always been a wet mix working on a small area at a time. I set my level heights on either side and then use either a string line or straight edge which I usual use a 1200 - 2400 spirit level (usual method) to check and maintain the height.

Nailbag

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