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.