Locating Radiant Tubing Within a Slab

How do you find those tubes so you won't puncture them when you're anchoring down equipment? March 26, 2008

Does anyone have a method to locate radiant heat tubing under a concrete slab? We have radiant heat in our shop and I have a machine that I need to lag into the floor.

Forum Responses
(Cabinetmaking Forum)
From contributor V:
I've just finished my own radiant floor for my shop and did the best I could to map out the piping before the pour just in case. However, there is just something unnerving about standing over concrete with $2000.00 worth of piping below, ready to shoot a lag into it. Best advice: Light a candle and drill! If you do hit a pipe, try radiantcompany.com. That's who I bought my system from. I think I remember seeing solutions for repair on their site.

From contributor A:
I would think that if you let the slab cool off, then turned the system on full bore, you might be able to use a thermometer to measure the difference on the surface. Do you have any idea about the distance it was buried and how far apart?

From contributor M:
There was a thread on this a while back and someone suggested heating it up, then wiping it down with alcohol and watching the rate of evaporation. I haven't done it, but thought it made sense.

From contributor F:
Contributor A is right. This is a long shot, but I am a firefighter full time, which gave me an idea. Talk to your local fire department and see if they have a thermal imager and would be willing to come out as a "training exercise" and use it to look at the floor. Do as contributor A says and have the thermal imager there when you turn on the system. The thermal imagers we have can detect differences in temperature of only a couple of degrees with sharp detailed images on the screen. This would allow you to see the floor heating up where the piping is first.

From contributor D:
If the slab was poured properly, the tubing will be under the concrete, not in the concrete. Use a depth gauge when drilling and only go as deep as the anchor needs to be, 1 1/2 - 2 inches for most anchors. The slab should be 3 1/2 - 4 inches thick or more, so that should give you a safety margin of 3/4 - 2 inches or more.

From contributor Y:
What kind of machine do you need to lag to the floor? Are there other alternative fastening methods available for use?

From contributor R:
Just a quick note. Radiant tubing should be in the middle for best response. I've seen it anywhere from the bottom to the top.

From the original questioner:
Thanks for all the feedback. It's a vertical panel saw we're going to bolt down. I was there when the floor was poured and we left the tubing out of the area where the saw was going, but I'd like to move it some from the spot we had originally planned on, so some of the bolts would be questionable. I do think that if we only drill down a nominal distance we should be okay. The slab is 4" and the tubing was tied to the mesh that the slab was poured on.

The comments below were added after this Forum discussion was archived as a Knowledge Base article (add your comment).
Comment from contributor B:
Apple iPhones can be equipped with a FLIR device so you can see the heat spectrum of viewed objects. Go to the supermarket, get bagged ice packages, lay bags tight to each other in the area where you wish to place your unit, wait 15 minutes, quickly move the bags to the side and use your FLIR to view the pipe locations