Mold and algae are two common problems that can ruin the appearance of your home and perhaps even damage it. These two nuisances have a great deal in common. Both are living things, and both thrive in wet conditions. Sometimes they are even difficult to tell apart, as there are green varieties of mould. Fortunately, both algae and mould can be eradicated using disinfectant solutions.
Pour some white vinegar into your bucket, dip in your scrub brush, and start scrubbing the mould. Vinegar alone will kill mould about four-fifths of the time and will almost always be enough to kill algae. For a small infestation, put away the bucket. Put a little vinegar in a spray bottle instead, apply it that way, and then scrub.
Empty your bucket of vinegar, rinse it, then fill it with water. Use a sponge to rinse off the infested area with fresh water, then dry it with a rag. If you are doing a major exterior wall-cleaning job, use a hose instead and allow the sun to dry the wall.
Return with a bleach solution if vinegar was not sufficient to kill the mould. Two cups of bleach per gallon of water will be enough to disinfect the wall. Scrub with the stronger solution, rinse and dry as you did in Steps 1 and 2.
The reason for starting with vinegar is because it is milder and less toxic than bleach. You won't create chlorine fumes inside your house or kill garden plants with dripping runoff outside your house. If these are not concerns, go directly to the bleach solution.