Drilling through the slab

[Walter R.]

I need to drill 1/2 inch holes through the slab of my home to kill some termites under there.

How can I avoid hitting copper water lines in or under the slab? Gas and Electric runs in the attic.

[Speedy Jim]

Hmmm. wild ideas time-

Probably can't use metal detectors if there is rebar in slab.

Could use sens mic to listen for water flow.

Or...(I like this one best), use a welder transformer to induce large current in piping and use a 60~ pickup coil to trace the path of the hum. (At your own risk...)

You better map out the route of the drains too...

Jim

[bill allemann]

do you have hot water radiant heat in the slab?

[Walter R.]

No radiant heat, just water in and water out.

[RicodJour]

Never done it, but you should be able to locate them through infrared temperature sensing. Run the hot water until it's piping hot and then start looking for the warm line in the slab. You may have to pull up some carpet, but, again, theoretically it should pick up the heat difference even through the carpet. The line won't be as sharp, but since you want to stay well away from the water lines anyway, that shouldn't be a problem. The cold water line should run parallel to the hot water line - I've never seen it done any other way.

If you have a post-tensioned slab, I'd be more worried about hitting a tensioning strand than a water line.

R