The concrete block wall in our back yard separates our backyard from the neighbors, whose property sits several feet higher than ours. So standing next to the wall his grass is about head high. Parts of the wall have what I can only guess is seepage from his grass yard where the water and chemicals in the soil seep through the concrete. What can I use to cover that up permanently, without having to re-do it on a regular basis. Thanx!
Two things come to mind -
- if you have white stains, they might be a lot less noticeable on a whitewashed wall. And a porous whitewash is more likely to stay put than an attempt to seal the wall with paint.
- Even without proper porous backfill, it would probably be worth trying to drill some weep holes in the bottom of the wall, to relieve pressure.
"Ugly, white stains" suggests efflorescence, or the migration of salts to masonry surfaces. If that's the problem there's a reasonable chance you can clean the wall, though it may require some scrubbing to prevent the salts from dissolving and going back into the masonry. Of course if the mineral stains aren't from salts in the blocks and are migrating from your neighbor's yard washing them off will be a losing battle.
In an ideal world the neighbor's side would have porous fill and drainage, either along the foot of the wall or through weep holes. Heavy seepage is going to make any permanent repair difficult. Getting an expert opinion on whether adding weep holes would help is probably a wise idea. Ruling out that and extensive excavations in rough order or permanence you're left with:
Paint, which will likely fail relatively quickly. Even without the seepage paint doesn't exactly endure forever outdoors.
Parging, or covering with a thin coat of masonry. That can last a surprisingly long time even under less than ideal conditions, probably longer than paint. In your situation it sounds like you may need to color the coat to hide any new stains.
Veneering, which is likely your best bet for long-lasting but also the most work. Stucco, brick, and stone are all options that include a drip space between the wall and veneer when properly installed. Ideally you'd also add a cap to keep out rain and tie the two together visually.