Expert: Jim Hise - 5/17/2007

Question
I recently noticed that there were some squishy small pockets underneath the paint on the exterior foundation of my house.  These pockets are only found underneath the window which is above a flower bed outside the house.  When I poked a hole in the pocket in the paint, a bunch of white powder spilled out.  When I peeled the paint back in that area, the foundation appeared to be somewhat degraded in that spot.  The cement was not smooth, but rather I could see the small rocks in the cement and was really rough feeling and powder continued to fall off when I rubbed it.  I don't see this happening anywhere else on the foundation except underneath that window which is about 6 inches above the soil (which is a flower bed that gets watered a few times a week).  I was planning on repainting the foundation because it hasn't been done in a few years, and then I noticed this damage.  I believe the soil is alkaline in the area and the water from our well that we use to water the flowers is alkaline and rusty.  However, I try to be very careful not to get water on the exposed part of the foundation because it will leave rust marks on the paint(and the cement that is damaged is 6 inches above the area that would be getting wet). The age of the house is 20 years.  The only thing I noticed last year was a small infestation of ants around that area that were crawling on the foundation and the dirt and plants in the flower bed.  Could you tell me what this damage was possibly caused by? What do I need to do to fix it or reseal it to prevent it from happening again and so I can repaint the foundation?   Thanks for your help.  

Answer
Jennifer,
        Ants love water. Water is collecting on your wall. Lose the water and this should eliminate the ants. I think the wall may have been dirty in the areas which are bubbling and the paint, while still holding together, separated from the wall allowing moisture to infiltrate. My suggestion would be to scape all the loose paint and cement off, brush down the wall with Trisodium Phosphate, allow the wall to dry...use a good quality paintable concrete caulk to fill the voids...let the caulk cure...and then repaint. This problem is usually more cosmetic than structural.  good luck , jim