I recieved an e-mail about this so I thought it was good to start a conversation over here.

See attached pictures.

This is going to be a combination of three things. One or many or even a combo of the below.

1. Fungal Surface Degradation,

               The weep holes allow for excessive moisture to be carried onto one spot and the fungus and mildew will grow more heavily there. The filament root system of the growth will                     actually eat down into and remove the paint or finish on the surface exposing lighter or even gray stucco, etc. below. These look like stains but are actually erosion left in the                         shape of the fungal stain.

                There is no fix for this except for repainting the surface and in the future do not allow the fungal stains to get to the    point of causing damages.

2. Metal Oxidation from Frames,

                As the inside of the frames get moist from condensation they will oxidize. This oxidation the drains from the weep     holes and settles onto the surface below.

                A product like F9 Barq can help with removing 95% of the stain.

3. Hard Water Stain or Mineral Stain,

                This is when adhesives or other building products leech off mineral or other waste products and they settle in the         window frame box. Then seep out from the weep holes.

                A product like F9 Efflo will likely remove these stains.

Window weep holes can be problematic and customers rarely understand the mechanics behind these stains. They only wonder why you a professional cannot remove the stains from their building. However, these are damages you uncover not damages you have caused. The real culprit here is the customer that procrastinated to have regular cleanings done and only engaged you when things were too bad to ignore.

AC