All I can see are some patio slabs with a pair of feet in the shot. Where is the cover?
Can you take a shot from further away to try and give a fuller view?
that type is prevented from leaning over or blowing away by being attached securely to the house, so there is not much risk of the legs coming adrift
IMO you only need to screw it down to prevent a foot being dislodged by someone kicking it, riding their tricycle into it, or falling drunkenly against it.
I always use stainless coach screws in that sort of job. They have a hexagonal head you can turn with a spanner. They will not rust (though they may go dull and stain) which is a great problem with steel exposed to the weather. Giant plasplugs would be sufficient.
what is the best technique of drilling into slabs so that i minimise the risk of cracking them. for example would i not use the hammer function on a drill
Until last week I would have said an SDS+ drill. I recently had a bad spall.
I think yours are Indian Limestone or Sandstone slabs and will be fairly soft so an ordinary masonry bit will do it, but be a bit slow.
You could start with a small diameter drill and work up, that might reduce the risk of cracking. Especially if you are near the edge of a slab, don't use a tight-fit plug and screw with no space for expansion.
With luck somebody more experienced with these slabs will know better. Maybe ask in the "building" section if no other replies here?
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