Power Washer Power

Oct 11, 2005 10 Replies

Got vinyl siding which is in need of a wash to get rid of dirt and some greenish mold. I like the idea of having my own power washer since there are other occasional light jobs where it would be handy.



Can I wash the second story from the ground with one of the 1750 PSI electric models that Home Depot and Lowes sell for around $170? (Power washing from a ladder doesn't seem much fun, and the wife worries...)



If 1750 PSI isn't enough, how much is enough?



Thanks, Sam


Hmmm. Anyone know approximately the PSI of a garden hose with a spray nozzle? It's going to vary with the type of nozzle and the local water pressure, but I'm a power washer neotype and I'm wondering how they compare to a garden hose. Are we talking orders of magnitude?

Sam

I have a 1750 electric and vinyl siding.

You need to climb up so that the nozzle is about

4 feet from the siding. The hose is long enough so that a ladder will work.

A pressure washer is the perfect tool for the job. A hose is a poor substitute, I'd say inadequate.

In my experience (I've done my house 3 or 4 times) a garden hose is enough if all you are removing is dirt. However if you are trying to remove that small black mold that forms in the "grain" or anything stuck tight like bird crap then you need to get *close* even with a good power washer.

The unit I used was a 3250 PSI and with the "green" nozzle (second strongest) I still had to get within a few inches to get the siding really clean of the tougher stuff.

Many orders of magnitude. The garden hose will have around 40 to 80 psi on it depending on your water system..Your well or a city system. Either way it will be less than 100 psi. The power washer will be 1500 to 3000 psi. YOu get more volume with the garden hose.

I can't give you a definite answer but it is magnitudes. With that smallest cone nozzle I would guess a garden hose at 100-150 PSI. To clean that embedded stuff from the grooves you are going to need at least 600-750.

Of course if you swab on bleach and detergent you may get by with less.

BTW, siding should be washed even or down. If you wash up (as in from the ground) you can force water behind it doing a lot of damage to the substrate or the interior.

Colbyt

Do you actually think you are hitting the siding with that much pressure? While it may be rated 3000 psi, that is for the tiny orifice on the nozzle. If you hold it an inch away you will get that pressure on a tiny spot. Reality is the water is spread considerably, the distance is greater and the pressure loss is in many orders of magnitude.

Most city water systems run 50 to 110 psi.

And dont spray UP against the vinyl because it can force water up under the pverlap seam and into the wall beneath the vinyl. Spray along the vinyl sideways or angle it down.

You will not be able to reach the seconds story with any pressure washer- they are not water cannons. More pressure won't throw the water farther- in fact, you pressure from a distance will probably be less with a PW than a garden hose. To reach floor #2 you'll need a ladder, or an extension pole for the pw. I have a 2 story walkout- so in the back yard there is are 3 floors exposed. Eave height is about 30', and my extender is just about long enough. But the extension pole that long is pretty expensive +/-$130, and you can't power it with one of those small electric pw's. And it's a back breaker. But it beats dragging the pw wand up a 24' extension ladder. DG

>

Just a couple of notes. Too much power can put moisture into your home or damage vinyl siding. PSI is only one of two important measures of how well a product may work. The other is GPM (gallons per minute) Of the two, I would consider GPM the more important of the two. Most manufacturers tend to push the PSI because it is cheaper to increase than the GPM.

Thanks y'all. I'll do a little more research, but maybe I'll get a contractor to do the job.

What time of the year is best to clean off mold? Or does it make much difference?

Sam

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