When done incorrectly yes! Even a small pressure washer can damage siding, even knocking it loose. In inexperienced hands, the pressure washer can destroy window screens, cause leaking in window seals, blow off shingles and more. It can also remove paint on wooden surfaces and if you were only planning on cleaning your house, you’ll now be faced with repainting as well.
So before hiring a pressure washing company you might want to ask a few questions, like: do you have liability insurance, do you use any chemicals when washing, how strong are the chemicals you use, do you use chemicals at all and how much pressure do you use when pressure washing? All these questions are a good place to start when trying to hire the right company.