Stains On Brick From Aluminum Siding

[jnoden 15]

Hello all. I haven't been very active on here lately because I have been fairly busy however I just ran in to a bid that I am not sure about so thought I would get a 2nd opinion from some of the pros on here. This is actually a commercial building with a dozen or so windows that have streaks below the window sills where you usually see the black mildew streaks. These streaks are grayish in color so I assume that they are from the aluminum framed windows. Does anyone have any experience removing these? I think we have ran in to this on a couple brick homes and were not able to remove with house soap or sh. I am wondering if a light acid treatment might do the job. I will probably offer to go out for a small price to try a couple chemicals on one spot. I just want to make sure that I bring the right chems. Thanks ahead of time.

[Rick2 42]

Personally I'd try a thick mix of precarb first in a hidden location.

[Doug Rucker 31]

Did you demo a spot to see if it comes off with plain water. Using an adjustable wand? That just oloks like mold mildew to me. See it all the time around here.

[jnoden 15]

The pictures don't show the gray color of the stains well but it is similar to what you will find where brick meets the aluminum siding on a house. I dont think it will remove very easily but I havent done a test spot on it. It is about a 30 min drive from the shop so Im not going back out there again to test it unless they are willing to pay something which I am sure they will. Ill just bring all the chems that we have and hopefully we can remove them. Im fairly sure that if none of our removers work than there probably isnt anything that will work. I like to get other opinions from this forum on things like this because I am not sure we will be able to remove them. I wish it was only mildew.

[James 625]

The stains are from the Metal screens. Acid !

[Greco Pressure Washing 22]

The problem you are having is coming from the aluminum windows. What will remove these stains are citric acid. Have a your chemical supplier make it in a gel format so you can apply it with a roller or brush. This ensures that the product stays in place so it works, dwell time is important. Cover all windows since acids can etch glass. After 15minutes you should remove using heat. This is not a standard cleaning. This would be considered a building restoration and the cost should reflect that. You can contact me if you have any further questions.

John Greco

856.906.6181

[jnoden 15]

Okay thanks for the info. I didn't even think about the screens making the stains but that makes sense also.

[James 625]

Started as a window cleaner 25 years ago and have seen this type of stain many times.

[Craig 111]

Citric acid's your best shot.. non hazardous and I agree with John and James.