You can use a sponge a brush or an old spray bottle.
Using moter mix for crumbling concret walls.
Also take a look at the ends of the steel bars disappearing into the walls and see if the rust runs in as well.
Use sakrete 5000 plus high strength concrete mix for repair and building projects where concrete thickness is 2 inches or more and demands excellent strength.
Then mix your concrete with water mist the cracks with water.
The wall needs to be moist so that the old concrete won t leach moisture out of the mortar that you apply and cause the repair to fail.
Now you should apply water to the wall where you will be applying the mortar.
You want to make sure your new coat of concrete has a strong steady hold to the old surface.
Get rid of any dust and debris with a wire brush.
Hose the wall down or scrub it with a washcloth then use a metal file to smooth out any rough edges.
You want it damp.
Apply small amounts of water over a short period until it has absorbed water deep into the wall.
Continue chipping of the loose concrete until the steel bars using in reinforcing the concrete walls are exposed.
Using either a screwdriver or hammer or a combination of both chip off any loose concrete paint or old filler.
Modern epoxies are available that also make great repairs.
It is used primarily interior above grade non load bearing walls.
A stone wall can give your garden timeless appeal.
Once the steel bars are exposed brush away every concrete attached to them using a wire brush.
The ratio should be three parts stone two parts sand and 1 5 parts portland cement for a strong mix.
To repair small cracks or holes in cinder block walls you can use concrete.
To repair deeper concrete defects or to replace chunks of missing concrete just add small stones to your mix.
Type o mortar mix has relatively low compressive strength at only about 350 psi.
Adding mortar makes your wall stable and takes the worry away.
Always use the cement paint to bond your new concrete to your old.
Stone walls also look better with age.
Type o can be used as an alternative to type n for some interior applications but its exterior use is limited due to its low structural capacity.
They can be stacked without mortar but this requires stacking them just so.
First clean any parts of the wall that you plan to repair so the cement or mortar adheres securely.
Just before brushing on the cement paint to the old concrete this master craftsman said to get the old concrete damp.