I am looking to buy a pressure washer to keep various outdoor surfaces clean. What is the maximum safe pressure the vinyl siding can withstand to prevent damaging surface etching? Also, will vinyl brittleness in below-freezing temperatures be a risk requiring a lower pressure or to avoid this method of cleaning?

  • How close the nozzle is to the siding would be just as an important consideration, I would think. – Evil Elf Feb 6 '12 at 14:02
  • Yes, that sure makes sense. That and the type of nozzle. It might be better to just buy a sacrificial strip of this kind of siding. – Skaperen Feb 7 '12 at 23:06
  • A new test strip of siding will tell you nothing. What matters is that vinyl siding ages in exposure to sunlight and the elements, getting brittle with time. Every year it will get worse, more able to be damaged with a pressure washer. Your test strip will be an illusion. Not only that, but after some years, if you DO manage to damage the siding, replacing one piece will leave you with an ugly repair, since the color also changes due to sunlight exposure. If you can use a pressure washer, then you need to have water turned on anyway. Just use a hose. – user558 Feb 8 '12 at 10:50

Do NOT use a pressure washer on vinyl in below freezing temps. This is just asking to shatter the plastic, especially if it has had some exposure to the sun. That will make it more brittle. You don't need to clean the siding so often that you need to do this in the winter anyway. A hose has always been sufficient to clean siding for us, once a year in the summer.

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  • Thanks for the advice. Winter is when it gets most dirty. A garden hose is difficult to connect in winter because the pipes have to be cleared after use to prevent freezing. Hopefully I can find one with low pressure settings. If not, I'll just avoid the siding in winter. – Skaperen Feb 6 '12 at 4:28
  • Yes, but my point is that dirty siding does not hurt the siding, nor is there any real need to clean it until water is available. As far as the availability of water goes in the winter time, where do you think the water will come from to run that pressure washer? A pressure washer needs water too! And it uses a fair amount of water. If you are truly that desperate to clean the siding off in mid-winter, then you will need to make the effort to deal with turning the water on and off anyway. – user558 Feb 8 '12 at 10:41

Instead of the maximum pressure that won't damage the vinyl, find the lowest pressure that will clean it. Stay back from the siding a good distance and use a dispersing nozzle (one that fans out the water) to further reduce the pressure and to make the job go faster. Be sure to spray from above and in the direction that the siding overlaps so that you don't force water up or in through the joints.

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  • I've seen pressure washers with limit ability to adjust the pressure. This quest is to buy a suitable one. If I can find one that is adjustable over the full range, that might be a winner. If a cheaper one with little or no adjustment will be just under the damage level, it might be eligible, too. I'm going to be shopping for one in a couple weeks. – Skaperen Feb 7 '12 at 23:02

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