A concrete wall is the most durable and reliable foundation for a home or building. It can weather the elements and stand for decades to come. However, if these walls do not get enough sunlight, plant organisms like moss will soon invade and destabilize it leaving it vulnerable and less sturdy as the years go by. Moss develops and grows in areas that are moist and away from sunlight. So if your concrete wall is developing these organisms, then you will need to apply a myriad of techniques to remove the moss. This will ensure that your walls will stand the test of time.
Purchase a pressure washer. The very first thing that you will require to effectively remove the moss from a concrete wall is to purchase yourself a pressure washer. This tool will spray water or any solution with extreme pressure. This is effective for almost any cleaning job. It can remove moss, molds, and algae easily and with no effort. In your local hardware supply store, there are many models sold. Purchase a portable heated or cold pressure washer with the latter being the more expensive one. The cold pressure washer is better since the heated version can be dangerous as it can heat up to really high temperatures when used and if you accidentally touch it while still hot, then your skin will burn right off. The cold pressure washer does not carry this risk. Regardless, once you purchase one, you can use it to apply any of the chemical solutions that will be presented to remove moss from your wall.
Use ammonium sulfamate. This chemical can be harmful to plant life. In this case, you can apply it on the wall to eradicate the moss invasion. Go to your gardening or hardware supply store and purchase a can of this chemical. The popular brands for this chemical are Amicide and Fyran 206K. There will be instructions to apply this but it will typically consist of spraying it on. Good enough since you already purchased a pressure washer. While applying the chemical, make sure not to get any on the surrounding plant life as it can eradicate that along with the moss as well.
Use a sodium pentachlorophenate solution. This solution consisting of 1 part sodium pentachlorophenate and 3 parts water is an alternative in eradicating moss from a concrete wall. Mix the solution and pour into your sprayer. Spray onto the wall and let it sit for 24 hours. The next day, you should see moss falling off and withering. Make sure to wear protective masks and clothing, as the chemical is a carcinogen. Remember to spray the solution only if not raining.
Use a bleach solution. Another alternative solution is to mix ½ part bleach and ½ part water and pour it into the sprayer. Spray this on the moss and let it sit for 30 minutes or so. Use a firm brush to remove the moss that has detached from the wall because of the solution.
Use baking soda. If you do not have enough money to purchase a pressure washer, a good and cheap alternative is to sprinkle baking soda on the moss and allow it to set for 24 hours. Get a steel brush and brush the moss off the next day.
There are many other moss-eradicating solutions that can be used on your concrete wall. However, these are the solutions tried and tested. They are easy to apply as well.