retrofitting a pvc pipe thru concrete wall

[lennyf]

My second post here, still working on my signature..
Anyhow, IG, 25K, cast concrete walls, 8" thick, ceramics tiled. For some reason I need to add another 1-1/2" or two pvc pipes thru the pool wall. I do have an access to parts of the backside of the walls. what I ask is what size of hole to drill in the wall in order to accommodate 1-1/2" PVC pipe, and how and with what to seal it good. The drilling itself will be done using a diamond core bit, starting obviously from the inside tiled surface.
Waiting eagerly for any suggestion!

 

[duraleigh]

I would make the hole about 1/2" wider than the outside diameter of the pipe.

Then, pack and fill that 1/4" gap all around with a fast drying masonry compound, like one you use to set vertical decorative fence posts. I would not use caulk unless you can force it well into the wall

Drill a pilot hole through the wall so the core bit won't "walk" and you'll get a nice, straight hole.

I would not trust the core bit to not break the tile. I would manually chip or cut out the tile back just a little bit so the core drill doesn't touch it.