While there is lots of info on the internet and people as well as companies explaining their methods, here is a brief simple yet comprehensive guide and explanation of what soft wash low pressure house washing and exterior cleaning actually means.
During soft washing the surfaces are not cleaned relying on using high pressure to remove dirt etc, first soft wash chemical is applied using a low pressure pump ( see below a list of pumps ) and then after a few minutes dwell time the surface is rinsed off using low pressure higher volume pump and those are usually power washers with way oversized tips and nozzles for low pressure high volume rinse - now the important word is RINSE as you are to rinse the dirt etc off and not power wash it off.
Now keep in mind while soft washing can be the more gentle way for exterior cleaning like house washing or roof cleaning and can provide longer lasting clean surfaces then traditional power washing using just water at high presure it can also be a very dangerous and damaging - if the cleaning technician is not educated enought about the chemicals being used on how to and where to use what chemical and what strenght.
Are you wondering if we might be very expensive because we use this expensive big equipment and why are we using it ?
Now when it comes to the above equation, the answear is pretry straightforward- the bigger the equipment we use the faster as in more efficient we can be and are able to offer competitive pricing while still meeting our profit goals. Now in theory and actual practice as I have done it to prove a point, one could soft wash many things with a pump sprayer, garden hose and a ladder - but that is no where near efficient enough amd quiet dangerous, this is why we invest so much money and time to learn more and try more equipment to get better results at faster speeds while also making is safer and easier for the cleaning technician - many even 3rd and 4th story high walls can be cleaned safely from the ground without the use of ladders or lifts which is safer, often faster and less expensive .
Before i get into equipment i will mention chemicals, these are even more important to learn about first then equipment and you might quickly realize this business is not quiet as easy or fun as some make it out to be on internet, in reality you will end up washing many days in windy conditions or in ways where you wiill most certainly get these chemicals all over yourself so you should learn about chemicals first for your own safety - now this is just a basic info and warning for you to start learning about thse dangers, proper chemical uses and handling n depth.
There are reason why every year there is so much almost new equipment for sale from new comers whom quit and reasons beyond just $ making.
Here is a basic soft washing and power washing chemicals type list that you should know if this is something you would like to learn and do, but do not just learn what chemicals to use on what and how to remove something chemically - you should also know what to be carefully off, what other adjacent surfaces those chemicals might actually destroy, how to handle and mix said chemicals and handling as well as storage so you do not hurt yourself or others.
Many professionals like myself will use many raw acids and degreasers and make our own mixes BUT even more we buy as a ready to use or ready to mix proffesional product, some raw chemicals while much much cheaper are just way to dangerous to try to mix ourself as the health risks and even death risks are way to great to try and save some money. Please do yourself a favor and educate yourself and don't just take a quick tip from someone internet. All too often I see use this chemical works good yet no one mentioned to be carefull as for example you open a container with x degreaser powder and 1 tiny bead of powder gets into your eye and you might lose that eye, or one whif from an open container and you end uo in a hospital even you actually live long enough .
Now there are 2 main ways to mix soft washing chemicals,
#1 batch mixing:
#2 Blending mixing manifolds
Now you can make your own for a few hundred dollars with chemical resistant metering valves or purchase one professionally made from as little as few hundred to few thousands dollars. Just keep in mind just having a mixing manifold is the the biflg cost - a few tanks that will be needed and plumbing it with proper hardware will likely far exceed the manifold cost and can go quickly into the thousands of dollars .
Please keep in mind while picking equipment to try and work with, all equipment breaks and needs maintenance and repairs and in this industry it's quiet frequent so ask yourself first am I a handy guy whom will learn and like to do all this myself or I need someone to do all that so I should look and try equipment that a local vendor will fix for me. ( now let me give you a little hint - it is best to know your equipment really well and be able to to do most basic repairs in the field yourself or you might quickly find yourself really hating the power washing and soft washing business)
Now before I get into types of pumps used in soft washing I want to bring up that yes there are 2 ways to soft wash using a power washer without soft wash dedicated pump, one of the ways is using a down stream chemical injector and oversized tips but this works well with low flow power washer and with higher flow profesional equipment the % mix becomes quiet too low, xjet now this is high pressure chemical injection right at the tip of power washing gun or Lance yet still could be called as soft wash since it would be sprayed from many feet away from the surface.
Now the soft wash pump styles, many profesional power washing and soft washing companies will actually have on track more then 1 of these simply b/c different styles are sometimes better for specific job.
#1 The 12v pumps
These are quiet inexpensive from just a few hundred dollars, the actual flow output and pressure is enough for most basic soft washing as long as you don't need too long of a hose or shooting height, these pump do wear are quickly and are to be considered an items that will need replacement and if you do lots of work might be quiet frequent replacement.
These pump are usually self priming which is a huge benefit and can easily be used with both a mixing manifold and bath mixing.
While some claim they rinse with these too we found them way to slow and inefficient for rinsing and prefer a 8-10gpm pw.
We actually still use 12v pump for delivery of some of our soft wash custom mixes when bland manifold can not be used and high volume is not desired or problematic.
#2 Booster pumps
We have used the most popular one on the market and found the performance of them just phenomenal yet quickly decided to switch to a different style, the issues we did not like were that it was not self priming which caused a whole bunch of problems when the pump lost prime on one of the chemical lines, these booster pumps were maid to be used with water and not chemicals so they needed rebuilding that is quiet consuming and they need a generator to power them which adds equipment that takes space on the truck .
#3 air diaphragm pump.
Now these are chemical transfer pumps that will last a long while since this is what they are made to transfer, these need an air compressor to work actually and a high performance commercial one at that, the bigger the compressor cfm and psi the better they will work .
#4 gas engine powered low pressure high volume pumps.
Now this is currently our main chemical application type of pump, the performance is phenomenal, we can work very efficiently with this covering large areas very quickly amd sometimes even rise with this pump, these are self priming pump which is great, the downside is they are designed to bypass and no pressure switch - it can be used with a mixing manifold using a bypass loop but one has to keep in mind can't be too long of trigger as the bypass loop will overheat .
What's is a good profesional power washer for soft wash rinsing and power washing ?
Now when it comes to power washers for either power washing or soft wash rinsing most newcomers to industry and homeowners are probably thinking pressure, but most ever proffesional when we chat about these machines we talk about flow in GPM (gallons per minute) first and pressure second, the reason for that is most commercial power washers will have more then enough psi to get the job done (until you go long hose distances then it gets complicated with psi loss due to hose back pressure etc) so what matter for us is flow as the more gpm flow you have the faster you can work and finish the job.
Most homeowner and low end bidget commercial power washer will be direct drive where the water pump is installed directly on the engine.
More traditional power washers build for proffesionals will use either a gear box or a belt system to drive the pump as those far more durable, longer lasting, simply put made for every day all day long use and not a weekend warrior use but they do cost significantly more .
Now things get a little more complicated as at 4gpm you might be able to use it directly hooked up to a garden hose and have it as a portable machine or get by with a small buffer tank but once you get bigger 5gpm 8 gpm 10gpm or bigger then you need a large buffer tank.and you machine is no longer portable meaning you need hose reels and lots of hoses to reach the area that needs cleaning so things start to get real expensive real quick and you basic portable setup for say $2000 can go to basic $10,000 setup in a blink of an eye if you carefull or if you want more quality stuff you can spend $20,000 or $30,000 on equipment real fast and this still has to be installed which means labor and hardware which can just as well go from do it yourself for a $1000 in stainless nuts and bolts to custom build parts etc for yet another $10,000 -$30,000 real quick so consider all that carefully when picking what you want.
What is a buffer tank for a power washer ?
You might have seen power washing or soft washing companies trucks or trailers have these big tanks on them and those we call buffer tanks, the simple reason for them is many if not most any place can not keep up with a 5gpm machine and nevermind 8gpm or the 10gpm and 11gpm machines we use and we actually use 2 or even 3 of them at the same time and that's why the large buffer tanks are needed. Ideally you want to get to a job with full buffer tanks, our machines pull water from the buttom of buffer tanks and the clients garden hose or hosses fill up the buffer tanks from the top as we work. The bigger the machines and more of them the bigger the buffer tanks have to be or you will spend more time waiting on water fill ups then working.
By now you might have realized picking you machines is not as simple as the bigger the better - yes the bigger the machine the faster you will work but that also means other thing like bigger buffer tanks which are not just expensive in thenselfs but just to get one shipped to you might cost more then the tank- yes you can expect to pay a few hundred just for shipping a tank and if you go real big don't be surprised to pay a thousand or two thousand for shipping al9ne, not bigger buffer tanks also mean you need a bigger more capable more expansive truck or trailer to handle the weight.