Can you downstream a roof with a regular power washer?

I have a small hose to do but a steep roof. If you are trying to apply a 50/50 mix on the roof can you downstream it with a regular powerwash or do they not have downstreamer that will do 50/50. Also new to cling on . Bought the sample package what ratio do you use per gallon? thanks

My machine is a 4.0gpm


It will work but you need to add a squirt of dawn detergent and 1 cup of arm and hammer detergent to your mix. Apply, wait 15 minutes, rinse with yellow tip.

I thought you said you had to boost the mix with goat urine?

1 Like

No. You cannot effectively wash a roof through a downstream injector. Mix is not strong enough.

If I use dawn ultra do I have to dilute the squirt to a half squirt?

@Dirtyboy all I can find is Dawn Platinum. Would that work instead? Or reduce to 3/2 of a squirt?

1 Like

Somewhat ironically, I downstreamed a roof today. And it came out pretty good…

Sorry, forgot to grab a before pic


Uh huh…sure. Everyone always forgets the before picture. I bet it had 6" of moss too… :grin:

jk…I could see it working good on a metal roof that isn’t that old or is cleaned regularly.


I got pics of certain sections. Just no overall pic lik in the after shot.

1 Like

I’ve done a few smaller roof jobs with an X-Jet, no proportioner plug. Gets about 50/50 so I used straight 6% and it worked fine.

1 Like

I thought we were cutting down on disinformation?

I intentionally didn’t mention goat urine for that very reason.

1 Like

Self improvement, well done.:laughing:

All I can say is don’t schedule any work until you know how a downstream injector works, it would be a little cheeky to charge a customer to practise on there home.

Shhhh. Trade secret!

1 Like

no one is using the cling on roof stuff? and how much are using per gallon?

Cling-On is a proprietary blend of surfactants and dispersing agents that will not only thicken your mix it will also disperse your mix more evenly across the surface. Cling-on is also designed to rinse as well as it sticks. Just add 1 ounce of Cling-On per mix gallon of solution.

@bleachblaster that’s directly from the website. Gotta search a little. :wink:

Link Cling On

1 Like

In new to this, but from what I’ve read on this forum, downstreaming is almost never used for roof cleaning, because roofs require a much hotter mix than siding. It seems like people are using about 5% SH on roofs (someone please correct me if that is incorrect). Downstream injectors pull a ratio of somewhere in the neighborhood of 10:1, the hottest mix being around 8:1. With 12.4% SH and a 10:1 dilution you’re only getting about 1.2% SH on the roof. Too low for a roof, but fairly hot for siding (assuming people put roughly 0.8% SH on siding, again please correct me if I’m off on that).

If you have an XJet siphoning 12.5%, and your pressure washer is no more than 4 GPM, you might be able to get the mix hot enough for a roof. See this video about that and compare with what others say:

They say you can with that fancy $160 washmart injector…but who knows. No green surfaces in my parts