Follow the advise below for effective cleaning and mold removal from vinyl siding.
Some vinyl siding manufacturers don’t want pressure washers used on their product. Others allow them, but have limitations on the amount of pressure and the cleaners that can be used. Most will caution against the use of pressure washers around any opening in the wall. These include as windows, doors, electrical wiring, and plumbing. Do not aim the power washer upward as water may be driven behind the siding.
Use a garden hose with a nozzle that can be set to spray a mist. You want to avoid a powerful stream of water that can get beneath the vinyl siding. Some homes have waterproof membrane beneath the siding to protect the walls but many do not. The seams where siding sheets overlap can easily be penetrated. Corners and near windows in particular. These are where water can get in and wet the wood sheathing and framing lumber.
The problem in cleaning vinyl siding is that it is supposed to repel water falling downward. It is not designed for water being sprayed up from below. Try to wash siding pointing the flow of water downward. Shooting water upwards can cause significant seepage into the siding. Never aim a hose up at vinyl siding. It can cause massive amounts of water to seep behind the siding.
Liquid dishwashing soap in hot water making a sudsy froth works. It is an excellent cleaner for mold removal from vinyl siding. It can be applied from a bucket but it is easier to dispense from a hand-pump type sprayer.
Mold removal from vinyl siding with vinegar
Mix a combination of thirty percent white vinegar to seventy percent water. This is a natural and safe solution that is very effective and environmentally friendly.
Mold removal from vinyl siding with detergents and household cleaners
Use one gallon (128 fluid ounces) of water with two thirds of a cup (5 1/3 ounces) powdered household cleaner (Spic & Span® or similar) plus one cup powdered laundry detergent (Tide® or similar)
Use soft, long-handled bristle brush. A recreational vehicle (RV) dealership may sell you an extended soft brush used to clean the sides of RVs. These are a perfect tool for mold removal from vinyl siding. Use side-to-side motions to clean off dirt and to remove mold from vinyl siding.
Do not use chlorine bleach to for exterior cleaning. It is highly toxic for all plant life and will get into groundwater killing trees and bushes near your home. Oxygen bleach, on the other hand is environmentally friendly, adds oxygen into the soil and does a good job of mold removal from vinyl siding.