Hi,

I just used a portland-based fortified concrete as a morter to pack
around and support a new outdoor sillcock watervalve. It's pretty
strong on its own but I would like to use tapcon concrete screws in the
flange holes for added strength.

Is it OK to drill day old concrete to make the drilling operation
easier, then wait for it to fully set to install screws ---- or to
just wait until fully cured and drill conventionally?

Thanks for your time!