# Detergent use with pressure washer



## MikeUpte

Recently I purchased my first gas pressure washer. I wonder if anyone could advise me about the advantage of using detergent when performing such work as paint prep. cleaning on siding (T1-11, metal & fiberglass) I'm assuming there is a significant advantage gained by using detergent and that degreasing would be enhanced when the scum is hit with soap not just pressurized cold water alone, especially on non-porus surfaces? A couple of friends say they have never used detergent with their washers and don't consider it to be much advantage? This doesn't seem very logical to me so I'm looking to expand my knowledge base, if you will, on this subject. Many thanks to any and all who will enlighten me. ~~mcu


----------



## user1007

It depends on what you are cleaning. 

If you use detergents with a pressure washer make sure they are formulated for such machines. You never want to atomize things like chlorine or ammonia.

When all is said and done you are still going to have to take a brush or sponge to the siding if it being greasy or extremely slimey is the issue.


----------



## Thurman

You didn't say it, but I am assuming you are talking about injecting the detergent into the water which will be coming out of the wand. This may pose a problem. IF your unit siphons in detergents/additives _after_ the pump then you should be fine doing this. IF your unit siphons in detergents/additives _before_ the pump-this is not good. IF you have a real high end pressure washer with stainless steel internal parts--then you will be fine. Most detergents contain phosphates which are not good on most pressure washer parts internal parts, particularly if a large amount of water is not run through the pump after using detergents. I use a pressure washer in my business quite a bit, the siphon point is _after_ the pump (which I replaced the valves with SS ones), and only use Simple Green with this set-up.


----------



## MikeUpte

Thurman said:


> You didn't say it, but I am assuming you are talking about injecting the detergent into the water which will be coming out of the wand. This may pose a problem. IF your unit siphons in detergents/additives _after_ the pump then you should be fine doing this. IF your unit siphons in detergents/additives _before_ the pump-this is not good. IF you have a real high end pressure washer with stainless steel internal parts--then you will be fine. Most detergents contain phosphates which are not good on most pressure washer parts internal parts, particularly if a large amount of water is not run through the pump after using detergents. I use a pressure washer in my business quite a bit, the siphon point is _after_ the pump (which I replaced the valves with SS ones), and only use Simple Green with this set-up.


Thanks for your comments. Yes, my owner's manual says the washer is "designed for downstream pressure washer detergents." I am assuming "downstream" means injection of the detergent through the siphon hose occurs after the pump, not before? I glad you mentioned Simple Green in your response. That was what I was intending to use as a cleaning agent. From further research I have done, it appears that the pressure washer use alone will not be enough to do a thorough slime and grime removal from siding, metal soffit and fascia. I guessing I'll probably have to some manual scrubbing after an initial water pressure and detergent application followed by a second wash? ~~mcu


----------



## Tom Struble

pressure washing vinyl siding is not recommended,detergents can/will get behind it and can damage the housewrap


----------



## MikeUpte

Thanks Tom for pointing out something that should have dawned on me as a result of labor intensive hand scrubbing I've done over the years on the vinyl siding. As I work at it with the brush and extension handle it is apparent the siding does not fit tightly together nor is firmly held to the OSB sheathing underneath. Getting into my sixties I thought the pressure a washer would somehow be a "magic bullet" to make cleaning on all types weathered surfaces easier. I am starting see now, I probably need to scale back my expectations a bit.


----------



## Canarywood1

MikeUpte said:


> Thanks Tom for pointing out something that should have dawned on me as a result of labor intensive hand scrubbing I've done over the years on the vinyl siding. As I work at it with the brush and extension handle it is apparent the siding does not fit tightly together nor is firmly held to the OSB sheathing underneath. Getting into my sixties I thought the pressure a washer would somehow be a "magic bullet" to make cleaning on all types weathered surfaces easier. I am starting see now, I probably need to scale back my expectations a bit.


 

If it's vinyl siding you want to clean,go to home Depot and ask for Armor All house cleaner, you spray it on with a garden sprayer,wait 5 minutes and wash off with a hose,and it wont hurt any plantings or grass.


----------



## soap911

You can use a pressure washer to clean house siding but you must be smart about it. Let the chemicals do the work and use the pressure washer just for application and then rinsing using low pressure. Where people get in trouble is where they want the psi power to do the cleaning with water alone and that is when water gets pushed behind and under the vinyl causing mold, mildew and wood rot later. Simple Green is a good middle of the road cleaner. If you have lots of mold or algae you may need a use a separate "bleach" wash to kill that and once rinsed follow with the other cleaner. Do not mix bleach with any cleaner not listed as Safe with bleach. Hotter water also increases effectiveness of chemicals and cleaning but not too hot as that can also cause trouble for vinyl. My best suggestion is to find a qualified local contractor that has experience in this type of cleaning and leave your pressure washing to your driveway and sidewalk.


----------



## MikeUpte

Thanks a heap for your advise and warnings. ~~mcu


----------

