Loose paving slab

[Keitai]

Got one totally loose slab. Is this a danger? Best to wack some cement underneath? The others seem not to rock but is there anything that can be done to strengthen them too

 

[johnny2007]

If the base underneath is mortar, grind off an inch or so, clean all the dust and stick that slab back on with mortar.

 

[John D v2.0]

Not sure it will stick to mortar alone, personally I'd recommend removing any loose material, then getting a bottle of SBR and some cement and mixing to form a thick paste, then pour some in the hole and paint some on the slab back, then push it back in place.
Tips are don't walk on it or allow it to get frosted for a few days, also don't spill or drip it anywhere as it will stain, wash it off straight away.
You may be able to get a small amount of proprietary paving bonding that's ready mixed, to save buying in bulk as the qualities i bought in would cost you 30 quid and you'd waste most of it.
Good luck.

 

[Keitai]

Not sure it will stick to mortar alone, personally I'd recommend removing any loose material, then getting a bottle of SBR and some cement and mixing to form a thick paste, then pour some in the hole and paint some on the slab back, then push it back in place.
Tips are don't walk on it or allow it to get frosted for a few days, also don't spill or drip it anywhere as it will stain, wash it off straight away.
You may be able to get a small amount of proprietary paving bonding that's ready mixed, to save buying in bulk as the qualities i bought in would cost you 30 quid and you'd waste most of it.
Good luck.

I found 15L of sbr but would this do?

This and small bag of pre mixed mortar?

https://www.toolstation.com/everbuild-201-mortar-plasticising-admix/p60707

 

[John D v2.0]

that's not sbr and it's 5l not 15l. you would need this one https://www.toolstation.com/everbuild-503-premium-sbr-bond-bonding-agent/p18528
however screwfix is cheaper - or you can get a amore reasonable size https://www.wickes.co.uk/KA-SBR-Bond-Co-Polymer-Bonding-Compound---1L/p/139061

 

[Keitai]

Grout has gone does that affect whether slabs rock r just aesthetics? and that one loose slab i guess isn't a trip hazard where it is
Thxs for link

 

[John D v2.0]

Grout has gone does that affect whether slabs rock r just aesthetics? and that one loose slab i guess isn't a trip hazard where it is
Thxs for link

For flexible paving the slabs butt up against each other, but for slabs that are stuck down you would leave 10mm and point(not grout) the gaps. The pointing is important to stop the slabs going for a walk.
In your case I'm not honestly sure if they're designed to be pointed, i guess not but maybe someone else can chip in.
Good luck!