Core / drill 140mm dia into deep solid Concrete foundation.

Hi,

I have to make holes in a solid concrete foundating, for setting in aluminium columns about 250mm deep. The concrete is much deeper, so if I core drill it won't be like going through a wall, I won't come out the other side.
The bottom of the core will still be solid concrete.

How can I make these holes? Do I need to core and then drill many holes and then break it out a bit at a time? Or is there another way?

The columns are 140mm x 60 mm and till go in about 250mm. Once in I will concrete them into the holes, but how can I make the holes???

Please H E L P !

Drill it out with a core drill and then use a kango to break out the material in the middle.

You don't want to be using one of the handheld drills for this it will take forever, get a proper Hilti core drilling rig with water cooling, they can be hired or best to get a specialist company in, they may well stitch two or three 100mm holes together so you get an oval hole which would better suit your rectangular posts and also be easier to break out the waste.

Some thing like this or the larger is what you need
http://www.hss.com/g/1122/Dry-Driller.html

Jason

PS you will need more than a 140mm hole to take a 100x60 rectangle, corner to corner it will be about 152mm

Thanks for the reply. I'll give it a go!