Pressure washers power through some of our least favorite cleaning jobs in no time. It’s just plain satisfying to see the accumulated grime of a year (or three) blasted from our driveways, walkways and decks with nothing more than the concentrated force of water. While it’s understandably tempting to apply this labor-saving technology to all our cleaning tasks, pressure washers can cause serious damage to some surfaces.
What can you clean with a pressure washer?
Cement Driveways and Walkways – Definite Yes
With rare exceptions, cement can easily withstand the force of a high-end pressure washer. Cement is best cleaned with a pressure rating of 3,000 psi and a flow rate of four gallons per minute. A faster flow rate not only gets the job done more quickly, but also flushes the muck away more effectively.
Decks – Mostly Yes
Hardwood decks can generally withstand pressure cleaning. Pressure treated pine can also generally be cleaned with a pressure washer without causing any etching or other damage. Older generation composite decks don’t do well with high pressure cleaning but the newer generation composites can tolerate gentle pressure washing. In all cases, start with a lower-pressure nozzle and test on an inconspicuous area.
Siding – Maybe
Certain types of siding, like fiber cement and vinyl, do well with pressure washing. Aluminum siding can usually be cleaned with a power washer but is prone to denting, so proceed with caution. If it isn’t compromised or rotten, wood clapboard siding does well with power washing. Be aware of the possibility of lead paint in older (pre-1978) houses. Shingled siding should not be washed with a power washer.
Roofs – No
Roof cleaning with a pressurized steam of water is both dangerous and potentially damaging. Shingles can be blown loose, or stripped of the embedded granules that serve to extend the life of your roof. Mortar and flashings can be compromised. Pressurized water can seep under the shingles and even the roofing felt. Finally, the blowback from a power washer makes using one while on a ladder extremely dangerous. You can do some roof washing but it is best done using pressure-less system.
Cars – No
Though most of us have seen our neighbors wash their cars in record time with a power washer, the practice does more harm than good. Paint can be chipped and scratches enlarged with the force of the water, which can lead to rust. Water might also force its way into places it shouldn’t go. In the end, a garden hose, bucket of soapy water and some elbow grease are your best bet.