"Charles Spitzer" wrote in message

"Larry Johnson" wrote in message
...
We have a woodburning fireplace we are converting to gas logs. I am
trying to drill a hole to accommodate the gas pipe through the floor
in a front corner of the firebox to a utility space under the house.
I get through the firebrick, about 3 1/2", and then hit something my
carbide bit cannot penetrate.

Does anyone have a suggestion how to detect what I'm hitting? Do
they use steel plate reinforcement in fireplace construction? Any
help is appreciated.

there was a steel plate in the top of mine. can you look at some
shavings/dust coming out of the hole to see what it is? reinforced
concrete (you hit rebar)?

A neighbor has a pencil magnet. I'll see what that tells me.