Efflorescence can plague cinder block walls as well as stone.
When water seeps through basement walls, the dampness eventually evaporates but it leaves behind dissolved salts that show as a white deposit called efflorescence. If your basement has an obvious leak, you'll need to redirect water drainage outside and fill the opening or find another way to stop the leak, before focusing on repairing the efflorescence. But even without an obvious leak, water can gradually leach through cinder blocks and create white stains. If that's your situation, the repair requires two steps: cleaning off the salts and preventing them from recurring. Does this Spark an idea?
Instructions
Cleaning
1. Brush loose particles from the wall with a wire brush. Mop or sponge clean water onto the basement wall to wet it, in the area with efflorescence.
2. Don rubber gloves, old clothes with long sleeves and eye protection before working with acid. Pour 12 cups of water into a bucket and add 1 cup of muriatic acid.
3. Scrub the wall with the acid solution, using a bristle brush, to remove the efflorescence.
4. Rinse the wall thoroughly with clear water, using a mop, clean brush or sponge. If one treatment doesn't remove all the efflorescence, repeat in the areas where it remains. Wait for the wall to dry.
Sealing
5. Clean out and undercut any loose or missing areas of mortar in between blocks to make the openings wider at the back, using a chisel held at an angle and hammer. Undercut small cracks in blocks the same way.
6. Place a small amount of hydraulic cement powder in a tray and mix in enough water to make a thick mortar, using a trowel or your hands protected by rubber gloves. Spread it into the cracks with a trowel or your hands, forcing it to the full depth of the undercut that you chiseled. Smooth the surface while the cement is still wet. Let the cement cure fully, according to the time recommended on the label.
7. Paint the wall with masonry waterproofing paint using a large nylon paintbrush. Work it well into the rough surface of the wall. Let it dry overnight.
8. Apply a second coat after the first is dry.
Tags: wall with, brush sponge, obvious leak, remove efflorescence, rubber gloves, trowel your
