We have an apartment in Port Hedland WA.( Extreme humidity and heat) It's relatively new( 3 years old) but there was mold all over the ceiling and along the walls following the air con pipes to the out door unit. When we got it repaired the repairman said it was insulated with the wrong material.. He changed it to a thicker material. The builder said it was because the air con was a bit dirty and needs cleaning more frequently in hotter conditions. . I have pictures of before and after and can send so you can see what was before and what is now... but would really like some input as to what caused the mold. any ideas.. ? Thanks liz Hope you can help Liz

  • Hello, and welcome to Stack Exchange. Those pictures would be helpful; if you can include the actual pictures, edit in links to the pictures and someone will be along to edit the actual pictures into your question. Mar 29, 2016 at 11:21

2 Answers 2


Yes, if it wasn't insulating nor tight to the pipe & therefore trapping & holding the condensation water. You basically had a very thick & long wet sock in the room that never dried.

Now that the correct insulation material & method has been employed. Completely spray & let soak for a few minutes & then sponge wash the moldy areas with a solution of 1-part Bleach to 3-parts water. Re-painting may be needed if the walls are on the darker side.


Please be aware Bleach does not kill mold. https://www.normi.org/articles/bleach-mold.php Moreover, pictures would greatly improve our chances to help you. Things I would suggest you to look for is condensation in the ducts. This can occur when there is a leak of cold air in the duct work. This creates a heat exchange between the hot air outside in the duct work and the cold air inside the duct work. This condensation can start dripping and generating moisture. I would use a FLIR camera to detect moisture or heat around the duct work. If you do have a leak you can apply foil tape and mastic to seal the leak. Hope this helps.

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