Message Board Thread - "flies due to moisture"

Back to Threads | Back to Forums

TitleByPosted On
flies due to moisture Ted Berdowski 4/15/2007
Hi everyone!

Im New to the forum.

Im currently experiencing a problem with moth flies in a ground floor apartment on slab construction. The flies are due to a moisture problem under concrete or in a wall. I set up tents as shown in the image to determine where the flies are coming from through out the unit.

I did irbwa but saw nothing of interest. The out side air temp was 3.8C or 38.84F and the indoor temp was 22.2C or 71.96F with RH of 46.4%.

The area in question where I was cathing flies was on an interior cinder block fire wall separating 2 units. Because its an interior wall it shows no temp differentiation. How might I change the wall or floor temp to note any differentiation.

Any help greatly appreciated
Re:flies due to moisture JNTOOLS 4/15/2007

If it is moisture you are looking for using a thermal imager, a Delta-T between the two units is not always necessary. I am assuming there is insulation between the framing over the block separating firewall. If water is entering the block fire wall and the insulation is wet, you should be able to see the anomaly. Because water has a relatively high thermal conductivity, wet insulation will transfer heat more rapidly than dry insulation and will affect the IR patterns accordingly. This happens as a cool spot when evaporation is taking place.
You can verify the anomalies with a moisture meter.

If you need to see more detail, there are several options. First you can cool of the unit that you are viewing from and or heat up the opposing unit. There are also other options that are more difficult like loading the wall with evenly distributed heat and than letting it cool off this can be a little tricky. This is similar to roof inspections using solar loading or doing EIFS inspections.

J. Nachman
Longwave Inspections Services

Re:flies due to moisture Ted Berdowski 4/16/2007
Thanks For the reply "J"

Forgot to mention core slab ceiling. No insulation in ceiling or wall unless its vermiculite in the cinder block

  • Back to Threads
  • Back to Forums


  •   Copyright © FLIR Systems, Inc 2012