Let’s talk about American houses and construction


The pressure from a softwash system isn’t enough to remove bird poo, insect nests, mould - especially lichen and many other contaminants.

Hoping someone an explain, because as far as I can tell, it’s just an effective chemical delivery system that bleaches, but doesn’t remove anything?

Constructive answers please, I’d like to see the light, if there is one :slight_smile:


Yes a 12 volt system isn’t enough pressure to remove stubborn stains. That’s why we use a pw to rinse with a soft spray tip. We also use booster pumps to rinse as well as apply.

Using a pw with low pressure tips is soft washing.


Thanks for the input :slight_smile:

I’ve been doing house washing for four years (downstreaming) and using a rinse tip will 100% not remove 80% of mould. Won’t touch lichen, bird poo, insect eggs etc.

You could stand there all day with a rinse tip and the black mould on the gutters for example would still be there. Pressure is needed.

With a softwash, you’re basically hitting it with a high concentration of mix and bleaching. The following rinse would only remove light dust/dirt?

I just hit a shed with 3000psi to get the mould off. I still had to focus on many places to get the lichen off.


I’m like 99% sure I could get that off with just chemical and not need pressure.


Need a bigger injector/hotter mix it absolutely will remove about all algae and mold from siding. A roof mix will also kill lichen sooo… get a new injector.


I have to agree. I know I could clean that with a chemical app and low pressure rinse. I dont know to many surfaces that need to be hit with 3000 psi


I would have added a little red raider to my mix for that pole barn.


New here?


Not sure why that is hidden @Ikii


Here was some stubborn mould, after I hit it with the normal downstream solution (maybe 1%) hit it twice and it wasn’t cleaning up, so I mixed a 3% batch mix and used my 12v pump to apply, rinsed it off with low pressure nozzles, looked brand new.


@Jwind there’s no problem with my injector, it’s the best you can buy - according to @squidskc :slight_smile:

Thanks for all the input. I can’t go any hotter than 2% on a house or barn though.

Again, the problem isn’t the mix. I can spray NEAT SH and surfactants onto the eaves of a house with insect eggs on and nothing but pressure will remove them.

It may work for you, all good.

For the record - I sprayed half that shed with 50/50 12.5 SH and the other half was a downstream mix.

Both applications vanished the mould, from a distance - but it’s still there. Low pressure removed the fluff. High pressure was needed to remove the rest.


No offence @steve076 but that’s very, very light basic mould.

This is a typical job I do daily. It always, without fail needs high pressure. You can’t simply rinse it off regardless of the chemicals you use.


That looks more like lichen than mould (especially the 1st pic), from things I read on another forum SH isn’t strong enough to remove the lichen I read that alkaline salts added to the mix, I don’t imagine it would be good for the grass or other organics in the area.

Here in Queensland with the humidity many of my house washes are annually, I don’t really see lichen but from roofs, TBH I find here with our roof surfaces/constructions that greatly differ from our neighbors in the USA, all roof cleans I do I use a rotary surface cleaner. Its just faster to give it a 2% pretreat then wizz it off lol.

Just soft washing tile or colorbond takes much longer and uses bulk amount of SH and multiple applications.
2% is as strong as the manufactures specify for colorbond.


You make a good point about the structures and roofs etc. completely different.

…wait, you just said you use a surface cleaner on a roof? Wait for it…

Ha ha.

Thanks for the chat :+1:t2:

I’ve been thinking of adding softwash for a while, and so I used that shed to test a few things today to decide.

The fact that I could apply hotter chems was a good thing, also the 12v peace and quiet was very appealing!

I think I’ll be giving it a miss and sticking with the downstreaming.


No idea why I cant see it.
maybe @Steve or any other admin could see about it.


That seems like a very easy soft wash. What gpm do you have and what size injector. Also what temperature are you washing in.


Hey @HydroPlus :slight_smile:

Did you zoom into the very first pic? I chose this because it had green, black, orange and lichen mould.

I’m working in 90F. 20% injector. 4GPM.


You’re right. You’re not going to get embedded lichen off immediately with softwashing or downstreaming. You can kill it with softwashing and it’ll eventually disintegrate and fall off, but if you need immediate results, then yes, you’re going to have to use some pressure.


Thanks @Racer

Immediate results are needed. We’ve not had rain where I am for a good while, so no chance of the weather taking care of it.

Also, I like to leave a property looking perfect and impressive - gets the neighbors taking :wink:


What are the roofs made of that you’re using a surface cleaner on? Surely not asphalt shingles.