Possible mildew/mold problem on exterior paint solutions?

ohman

Hi all, thanks for reading this thread.

I found that we have some stain (mildew?) on some of our exterior walls, here are two photos:





My questions:
1. Are these mildew? If so, should I be concerned that it might have some health concern (it's in my front year, outdoor)?

2. What's the best way to get rid of them? Would using some sort of mildew remover (with bleach) work?

3. What might have caused these mildew (or mold?) to grow? Moisture? Should I be repainting it? What would be the best way to prep the surface and then repaint it? I think we used Kelly Moore Alkyd-based (oil-based) paint to paint these exterior walls/fences (stucco/concrete) about 4-5 years ago (1250 Acry-Shield, I think, which is discontinued as no more oil-based paint is allowed in California)...

Thanks!

ohman

By the way, those exterior wall (fences) are concrete walls.. and I found this product on amazon which I'm thinking of giving it a try:

http://www.amazon.com/gp/product/B001CSF44G/

There is also a video on youtube which seems to address similar issues, thoughts or comments?
http://www.youtube.com/watch?v=_iVNjpipYto

Thanks!

Will22

Mildew is caused by moisture, humidity , and shade generally (vegetation may also be a factor). Oil based paints can also attract mildew growth, as it may feed on the organic content in these products. The best cleaning method is to utilize a product like Jomax (follow the directions). Otherwise mix a solution of 2 ounces of non-ammoniated liquid detergent, and one to two cups of chlorine bleach to a gallon of water. Apply it with a soft brush, allow it to sit for maybe 15 minutes, and rinse well. Painting over mildew will not eliminate it, and it can actually grow through the paint film.

Canarywood1

The Mold Armor is what you want,but get it at Home Depot in a gallon container,much cheaper and apply with a garden sprayer,excellent product.