You can use the spray cleaner while working from a ladder -- although scaffolding is better -- but practice at ground level first; the force of the spray against the house could knock you off a ladder if you're not careful. Some of these machines come with separate containers you can fill with cleaning solutions or anti-mildew solutions. Sprayers are so powerful that ordinarily you probably won't need to use a cleaning solution; if you do, remember to rinse the surface with clean water afterward.
If you're lucky, all your house may need before repainting is a good, healthy bath. Wash it down with a hose, and go over stubborn dirt with a scrub brush and warm, soapy water. Or wash it down with a power washer. If you're not so lucky, then you just have to face the fact that a time-consuming and dirty job lies ahead of you. Do the job well, and your paint job will not only look better, but it will last for five to eight years on average.
The time needed to complete an exterior paint job varies depending on the size of the home, the condition of your home’s exterior, the weather conditions and type of paint used on the job. An average project lasts 3-4 days, while a complex project may take a week or more. Additional time may be needed to fix loose or damaged siding or add primer to areas without coverage. Your painter will provide a timeline that explains how long the project will last and will schedule the job to avoid inclement weather.