Bit of help/advice on first roof job

Novice pressure washer here. Started business 3 years ago with window cleaning. Added gutter cleaning, interior high dusting, and dryer vent cleaning (as well as other add-on type services) as we had opportunities and it made sense to do so. Added pressure washing last year mostly starting out with various building exterior cleaning jobs that I got a hotsy 4 gpm 4k psi unit to do. We then picked up a monthly 5 store restaurant chain that we did flat work for and I got an 8 gpm 3500 psi Mi-T-M hot water skid set up on a trailer with two 300 gallon supply tanks and enough room to add more equipment later if desired. (seem to frequently come across commercial buildings that don’t have a working exterior water supply) I have of course a surface cleaner with this and a dual hi-lo pressure lance as well as the 24’ extension lance/pole which we never use.

Got my first request for a roof clean from a group of HOA condos to clean their terra cotta tile roofs on 15 buildings(specifically just the North and West sides that have problems). They have the black bacteria growth and in some places lichens. The roofs are very steep and only go up 4 or 5 feet in most places around the outside border of the buildings with a flat roof of TPO in the middle. A lot of the areas needing cleaning are above patios and balconies.

I had done many hours of getting my feet wet pouring over :wink: a ton of information here a few months ago. Spent several hours tonight refreshing and still feel a little lost or just unsure of not knowing what I don’t know. My plan at this point based mostly on what I’ve read here so far 1. do a pre-soak on the building walls, patios, and surrounding plant life 2. With 12.5% sh and surfactant treat the roof area to be cleaned from bottom to top using this foam cannon I have ( set at 50 oz. per min (should be roughly a 20:1 ratio water to chemical) with my 8 gpm machine while ground guy follows doing a continuous rinse on building walls, patios, and surrounding plants with the 4 gpm machine 3. by the time I’ve finished applying treatment it will have dwelled for probably 10 or 15 min and be ready to start final rinse from top of roof down finishing with rinsing off the greenery.

So any straight forward specific advice, tips, pointers etc would be much appreciated. In addition to what you might have to tell me, I am specifically concerned about the following:

  1. Use the foamer or get an xjet or xjetm5 or jrod or forget softwashing altogether on this job and try to use the surface cleaner from the flat roof?
  2. To cover or not to cover greenery?
  3. Concerns about chemical reacting with TPO flat roof or bleaching stuff on patios etc.
  4. How much chemical should I expect to use on one of these buildings?
  5. Any reason my current equipment won’t be sufficient to do this job since I have the low pressure lance and/or could use a jrod or the foamer?
  6. Need to capture water from downspouts off the balconies or just let go; use of gypsum?
  7. Any particular surfactant? My local pressure wash supplier has recommended Easy Peak Roof Restorer made by same company that makes Taginator for graffiti removal which has worked nice btw
  8. Based on the pics any idea how long one of these roofs will/should take for an average experience crew of 2?
  9. How many gallons of bleach and gallons of surfactant would I expect to use on a roof with this? Is there ever a cause to have to repeat the process?
  10. How much surfactant should be added to the 12.5% bleach?

More general questions

  1. Is the ability to more easily and precisely proportion/control dilutions of chemicals the only advantage of getting a 12v softwash system like the Water Dragons from over using my pressure washer for softwashing the ability?
  2. Any concerns for run-ins with legal authorities from epa, health and environment state depts, city waste water/ground water officials etc
  3. In conjunction with number 2, is there any research on dilution amounts and sds sheets specific to those dilutions as well as chemistry breakdown time frames and components?
  4. Seems to be quite the mix of preference on process with one end of the spectrum being treat the roof without rinsing and just let the rains rinse on one end, but then on the other end of the spectrum pre-soak, then cover all greenery with tarps or tyvek, then put something to capture water from downspouts, then cover or tape off tons of stuff on houses such as cameras, stained wood, etc, then treat house, then rinse everything thoroughly, then maybe even rinse greenery a third time for good measure. Thoughts?

Thanks in advance for any and all help.

I can see why people get “grumpy” after years of being on here. From one newbie to another if you have that many questions I would pass on the job. Most of the anwers your looking for can be found on the forum.


Most effective way I’ve found to clean those is spray them with roof mix then wash with about 500 psi .
Your going to need a lift.
The nozzle I found works best for us was a 15020 nozzle for 8gpm

1 Like

I wouldn’t even clean it until the remedial work was done.

Just in that pic there are loose tiles and some actually missing :open_mouth:

Also, no gutters, onto deck, onto electric meter/box…


Thanks for the tip.