Fun with FLIR! What do you conclude?

Thought to post this from a recently completed inspection due to frosting in an attic. Here are some details and a couple of images;

  1. 4:12 slope gable roof.
  2. Outdoor temperature is slightly below freezing. Frost building up under the plywood roof deck.
  3. Turtle vents all covered with snow. Ample number for attic space.
  4. Diagonal pipe is a bathroom exhaust pipe and the vertical is a sewer pipe.
  5. FLIR image (Blue is cold and red is warm)


What can you surmise from the images? Not really looking for advice but thought it would be fun to throw this out there as a “puzzling post!” Mwuhaha! Maybe lighten up the place a bit.


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Had to like this post before i even read it.
Now this is worth reading!

Yep, way too much heat escaping that sewer pipe area
Might be worth dealing with it to stop condensation/frost in attic.


Vent hose from the fan is leaking. Got a lot of heat transfer to the deck.

Was somebody taking a hot shower with the fan on?

Yes, the telltale was not so much the pipes appearing warmer, as they typically are in a cool attic, but rather the heat buildup due to the bathroom exhaust seeping up along the underside of the roof deck. First thing, when possible, the rigid bathroom fan pipe should be replaced with an insulated flex pipe. The flex pipe will then partially lay on the insulation and then turn upward toward the exhaust receiver. In doing so, it serves as a natural catch for accumulated condensation puddle which tends to drip from bathroom fans. Secondly, a flex pipe end tends to be easier to fit into a receiver on something like a Primex Gooseneck exhaust whereas an insulated galvanized pipe is a pain in the arse to finagle. The fan was left to run but nobody was showering during the inspection. If someone was, the resulting fog would have been quite noticeable. Last thing, and I’ve seen this numerous times, is that foggy,frosty attics tend to freeze the insides of static turtle vents. The fins which keep out the critters become clogged with hoar frost and render them useless.

Solution? Move to a tropical Island and screw the cold weather!!

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