Jay Markanich's Blog

Can you see the leak behind the wall?  A thermal camera can.

Of course, a thermal camera doesn't really "see" anything.  But it detects electromagnetic radiation that you and I cannot see. 

Looking behind the water heater there seemed to be some small spots of mold.

And on the floor molding there looked to be some slight stains.

Picking out a point on the wall it was obvious there was no staining.  And to the touch there was no evident moisture.

The moisture meter, however, detected moisture at the point you see here, and to the left.

How much moisture?

At the point in the photo it was 80% (the white gage). 

Moving the meter to the right the moisture got progressively less.  And to the left, and down, it rose gradually to 100%.  That seemed odd.

This wall abuts the powder room behind.  The moisture meter there similarly registered moisture in one part of the wall but not the other.  So the moisture pattern was consistent in both rooms.

Still, there was no staining in the walls anywhere.  And the powder room was recently completely painted.  Why was it painted?  Were there stains in the wall?

The thermal camera shows a straight, vertical line on the wall.

That line is right where the moisture meter is set in the photo.

To the right of that line the meter registers gradually less, and to the left of that line it registers gradually more moisture.

Clearly there is moisture there, apparently being blocked by a stud.

That, and the lack of staining, seems to indicate a very slow leak.

Interestingly, and something I had not noticed before, there is a slight discharge of water from the water heater.

The temperature at the service pipe over the water heater, measured by Sp2, is 88F.

And the warmth in the pipe can clearly be seen entering and traveling up the wall.  It gets gradually cooler, but still retains some heat.  There is a slow movement of hot water!

The spot measured at Sp1 is 73.5F.

SO WHAT WE ARE SEEING IS A VERY SLIGHT LEAK IN THE HOT WATER PIPE WHICH SERVICES THE HALL BATHROOM IMMEDIATELY ABOVE!

Nothing could be seen with the camera there, or measured with the moisture meter, as it is all blocked by bathroom cabinetry.  But the hot water pipe going to that bathroom looks to be the culprit!

The water leak is small, but there.  With nobody living in the house there would be no reason for hot water to be moving from the water heater and up the wall.

The leak is so small it is blocked in the center of the room by the wall stud, and wicks down the wall to where it only manifests lower on the wall, clearly seen in the second thermal image above.

My recommendation:  sometimes it takes a thermal camera, like Mighty Mo, to do a complete diagnosis.  Of course, just like in 4th grade math class you have to check your work!  The camera, working in conjunction with the moisture meter, is able to not only see a temperature pattern on the wall, but help diagnose what is going on.  The moisture meter confirms the presence of moisture, and how much.  Maybe I should call the moisture meter Mini Mo?