Indian sandstone hollow sound

[Jamespf1]

Hi all,

First time laying Indian sandstone.

Laid on a 4/1 mix of sharp sand. Semi wet mix. SBR and cement slurry on the bottoms. Laid on a 50mm full bed. Lifted one and can see that they have been laid perfectly on a full bed or mortar.

After 48hrs the slabs have a slight hollow sound when I knock on them. Is this due to the bed not being fully dry yet or does it sounds like a installation error?

Thanks

 

[23vc]

How soon after laying were they walked on?
Probably fine, and if any turn out to be loose they can be stuck back down with an SBR cement slurry if the bed was good

 

[Jamespf1]

they were walked on after 24hrs. Probably that that’s done it. Okay will slurry them down if any problems. Thanks