New roof washing mixture?

In the past couple weeks you guys have been recommending a new roof washing mixture to me. I just booked 2 of the first roof jobs of the season for the next few days. However, my roof pump will not be here in time! I do have a 5 gallon pump sprayer that i will be using. What type of mixture would you guys recommend to soft wash these roofs? One of covered in small “crumbly” clumps of mold, while the other is mostly black streaking and some mold also. How long should i leave sit before a thorough rinse?

Reschedule, if you have equipment on the way…Seriously!


Agreed. You need a pump to clean roofs

i appreciate the input and i would like to reschedule one of them but the other insists it NEEDS to be done next week due to an event he is having at his home (nothing like calling the last minutes) anybody have any input on a roof mix i can use? As far as soft washing it off i play to use my washer with soap tip so its extremely low pressure. Im sure spreading the actual chemical is gonna be a PITA tho…

You know. I’ve been wondering if I could DS a roof mix? I mean if the standard mix is 2 gal of 12.5/3 gal of water and surfactant. Why couldn’t I do 5 gals of straight 12.5 with a stickier surfactant like roof snot? I’d hate for you to experiment on someone’s house for me but for the sake of science why don’t you give it a shot and let me know if it works :grin::+1:t3:


You could sub-out. If this is your first roof and have NEVER used a pump, you will have alot of things you will be unsure of. It is best to experiment with yours, family and friends that know of your inexperience and you can create your process unlike a paying client that will expect professional perfection, just my .02


Just pass on the job then. If your just starting out a bad review will kill your business before it gets going. What’s the roofing material. If its asphalt and walkable ( ideally single story) a backpack sprayer might work but you’re in for a rough day. Just rinse with a garden hose unless you have an 6+gpm machine. Good luck.

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In all seriousness. Could a really strong mix of SH be downstreamed on the roof? 5 gals of straight 12.5 SH and roof snot or dial dish soap downstreamed onto the roof. Just curious if this will work. I’ve thought about it because I cleaned a 2 story home and noticed how clean the roof came from the SH runoff. I was using 3 gals of 10%/ 2 gals water and elemonator. I would think if everything was pre and post rinsed really well it would work. Thoughts? Maybe y’all can tell from the picture.

An x jet m5 makes a great Roof sprayer. With all that said I used pump sprayer for a while until I started getting serious about p.w and Roof cleaning. Pump sprayer are a lot of work but if the job pays good why not use what you got verses someone else getting it

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Like i said previously the roof cleaning kit has been ordered but wont be here in time… My main concern was spreading the chem (which i know is why i really need a pump) then i would be using my low pressure soap tip to further rinse the roof roof. I tried pushing the job but customer is insisting it gets done on that day. Luckily the roof is walkable!

@Alabama You can’t do it that way, unfortunately. The solution won’t be strong enough. For shingled roofs, I usually start with 40% SH / 60% water and go from there. No way you’re getting those ratios with a DS. Sorry!

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Where the heck did you order it from? Most suppliers are 2 days away at most. Can go to NT and buy a basic sprayer. How high and steep is roof? Post some pics of roof and we can give you better advice.

Damn. Oh well. It was a thought. I’m getting a pump before much longer but I love downstreaming. Quick, easy, and effective for most applications.

i dont have any pictures handy as they wont upload from my phone. However the roof is not steep at all and can be walked without an issue

Where did you buy your roof system from, upstate?

Where he bought the system from is irrelevant right now.

Downstreaming wont work, even undiluted in mix tank the final ratio wont be strong enough
Xjet may work, but if you sold the job saying you dont put pressure on their roof and they see you running a power washer it looks bad.
The best thing since the roof is walk able is to use a big pump up. Back pack sprayers tend to leak so i would not get in the habit of using them but using it once may be an option

Dont use backpack sprayers, they are dangerous and can leak and cause bad burns… also they can throw you off balance if you have too much liquid in them.

Now that that’s out of the way, go to Harbor Freight and buy a $25 ($20 after a 20% off coupon) 4 gallon backpack sprayer, and walk the roof with it. This will get the job done. Dont make a habit of it, though.

I did it on a roof not too long ago, when i didnt have a roof pump yet. Takes a little longer, but easily doable. That sprayer comes with 4 or 5 tips… i took the one that sprayed the heaviest, and used a nail to enlarge the hole so it really laid it on thick.

This is the roof i did it on:

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Well good you can walk it. Just be careful and I hope it’s not too large. You’ll probably go thru about a gal of mix for every 75sq ft if it’s not too dirty. Lot of pumping.

Wear a tyvek or rainsuit or something if you are worried about it leaking. Also you can disconnect the straps and run them through a couple of holes in a thick trash bag, along with the wand and pump lever, and wrap it all up if you were really worried about it.

Good points. What do y’all do when you come across roofs without gutters? I guess you soak the ground before and after application? Many houses that need their roofs washed around here don’t have gutters so I was wondering.

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