When I built my house I installed a wood board under the wall board for an anchor point for a future grab bar in the bathroom. I was in a rush and forgot to take a pic of where the board is. It's underneath ceramic tile over sheet rock and sunk into the foam. I know fairly close where it's at but I'd like to document it more accurately. Anyone have any recommendations for a stud finder, or similar, that can detect the density difference between the board and surrounding foam through an inch of tile and wall board? Another approach I thought about is to warm the tile wall and do a thermal image scan. I'm thinking that the board may act as a bit of a heat sink compared to the surrounding foam and cause the tile to be slightly lower in temp over the board. Any thoughts about the feasibility of this approach?

How wide of board did you install under the sheetrock? 2x? I built a spec house 6 yrs ago and I installed 2x12 between the studs for this reason in the MB. This might help.


http://www.ehow.com/how_4829242_studs-through-ceramic-tile-wall.html

Mac, is this an ICF wall or an otherwise interior wall?

If it's ICF, consider going all the way through and screw into the concrete.

I think you might get it on a thermal imager, particularly if it is an exterior wall.

Posted By robinnc on 19 Jul 2014 10:19 PM
How wide of board did you install under the sheetrock? 2x? I built a spec house 6 yrs ago and I installed 2x12 between the studs for this reason in the MB. This might help.


http://www.ehow.com/how_4829242_studs-through-ceramic-tile-wall.html

I think it was about 6" wide, 3/4" thick piece of Advantek subflooring or plywood. But then again, it may have been a 2 x 6. It's an ICF exterior wall.

I agree, heat the wall with an infrared lamp for awhile and then look for less/more heat in that area. The denser wood will initially absorb heat and then later, release it.

Otherwise, poking around with a thin nail might work. Or tapping and listening.

Dmaceld,
Dry the wall carefully first, a little water screws up the image.
The good news for you is that glazed tile has a very high emissivity so it is  relatively easy to image.
Find someone with a IR that has at least<50 mK resolution as you are not going to be seeing big temp differences
If the wood was touching the concrete behind it, I think it would be probable to see with a good thermal imager.
If the wall in question gets direct sun during the day, you may see effects from solar loading that will show the outline of the board, or possibly just a horizontal row of screws if the board was tap conned into the concrete. Probably about 4-6 hours after the sun hits the outside wall.
Other than that, you need maximum temp difference across the wall think 0° outside and the bathroom at 80° Alternatively you can try pulsing it with heat or cold as much temp difference as possible safely.
If I had to try it I would cool the room as much as possible for 6-8 hours, and then blast it with heat,  a few space heaters and a heat lamp for 20 min or so.
Image as it is heating up and then again after you shut the heat off. You may see something. Get the wall at least 25° F warmer than the surroundings for best luck.


Good Luck
Eric