ᐅ Experience with 3 cm thick patio slabs – do they break easily?

Created on: 20 Jul 2022 10:08
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Ypsi aus NI
Hello, yesterday we talked with a mason / all-rounder about our terrace. We are planning to use slabs measuring 60 x 120cm (24 x 48 inches) with a thickness of 3cm (1.2 inches). He advised against this. According to him, because of the thickness, the slabs cannot be compacted with a plate compactor without breaking. He also said that the base would gradually settle over time (even if it was compacted without the slabs beforehand), creating voids that would cause the slabs to become loose.

Does anyone have experience with this? Specifically, have such “thin” slabs been installed for a longer period, and can confirm or deny this?

Thank you!
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WilderSueden
20 Jul 2022 11:26
Would it be an option for you to store the panels? Although 3cm (1.2 inches) thickness is still quite thin for that size, it would prevent the issue with wobbling.
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Evolith
20 Jul 2022 11:55
We have 80x40 (3x1.5 inches) plates that have been laid in a gravel bed for a year.
A very important point is to always keep joint sand properly in place. I forgot to do this a bit this year, and they started to shift slightly. After brushing the sand back in thoroughly, everything was stable again. The problem is ants, which love the sand. You have to stay on top of that.
We deliberately had them laid only in the gravel bed for now because we want to test the plates (which are very light in color) first. If we are still satisfied after three years, we will remove them and install them permanently.
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Curly
20 Jul 2022 11:55
We installed our slabs in a drainage mortar bed and have had no problems with it so far.

Best regards,
Sabine
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Ypsi aus NI
20 Jul 2022 13:02
We decided against a concrete slab because we weren’t sure about the size of the terrace overhang or whether we wanted stone or wood.
Now we have chosen stone and found a slab that we like, but we are facing all these new challenges.
Thanks for sharing your experiences. I hoped that joint sand / quartz sand might be the solution. Installing it in a mortar bed is just as complex, expensive, hard to replace, and there is always the risk that it will freeze and crack.
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driver55
20 Jul 2022 13:23
The entire project depends on the subsoil.
Well-compacted ground, followed by a minimal gravel bed and a solid edging, will work.
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Ypsi aus NI
20 Jul 2022 13:55
@driver55
But that contradicts the other experiences mentioned here...
By fixed edging, do you mean lawn edging stones?