You should avoid using a pressure washer on any surface or item that could be damaged by the high-pressure spray, as some materials are too delicate to withstand the force.

Key items and surfaces to avoid include:

• Electrical Components: Never pressure wash electrical systems, as water can cause short-circuits and create a safety hazard. This includes utility meters, breaker boxes, electrical outlets, generators, and HVAC or air conditioner units.

• Delicate and Fragile Materials: Fragile items can crack, shatter, or be stripped by the pressure. Avoid pressure washing windows, glass, light fixtures, shingled roofs (especially asphalt), and stucco.

• Painted, Stained, or Sealed Surfaces: Unless your goal is to strip the finish, do not pressure wash painted surfaces, stained wood (like decks), or anything with a protective seal that could be stripped away. Be especially cautious with older surfaces that may contain lead paint.

• Soft Woods and Certain Decking: Delicate surfaces like softwood, composite decking, and antique or wooden patio furniture can be etched or damaged. If you must wash wood, use a lower-powered pressure washer with a wide-angle nozzle to prevent damage.

• Living Things: Never use a pressure washer on people, pets, or plants. The force can cause serious injury and will destroy landscaping.

Iron, or ferrous sulfate, is one of the fastest methods for killing moss. As such, you’ll find this ingredient in many lawn fertilizers and lawn killers. Vinegar is another solution for quickly killing moss. It takes just 15 to 20 minutes for vinegar to take effect. A harsher method is bleach, which also has a similar time frame for taking effect.

Having your roof cleaned can be worth it because it improves the life span of the materials on the roof. You won’t have to pay a roof replacement cost as often when you clean the roof regularly. 

It is not advisable to DIY a roof cleaning job. Cleaning your roof yourself could lead to hazardous falls, scrapes, and even burns, making this a dangerous project. Additionally, using the wrong cleaning solution or cleaning method on your roof could risk damaging it. While some markets offer a DIY roof cleaning kit, these products often speed up the deterioration of your roof.

To ensure that you and your roof are protected, it’s best to leave roof cleaning to a professional with the right chemicals, tools, and equipment to complete the job safely.