Slippery shale patio ????

[utterlydiy]

My mother who is in her 80's has a large patio area covered with shale slabs, which when raining or damp tends to be slippery and care is needed.

Is there any treatment to help make this more anti-slip or safer, but leaving the colours of the shale as they are.

Any tips ???

 

[utterlydiy]

Could such a treatment be used, using a small amount of sand mixed with a compound, but not effecting the shale colour.

 

[kevplumb]

just a wild shot in the dark