[Boba80]

Hi guys,

Currently scraping/brushing the moss off my roof using a extension pole and scraper.

I plan to treat it with a biocide containing BAC-50 or DDAC once im done removing the the majority of the moss.

Im not a professional so dont have a long reach water fed pole to get the product to the top of the ridge.
I plan to use a karcher pressure washer (at low pressure) to dispense the premixed biocide from a barrel but im unsure if the chemicals will damage the internals of the machine?

I'm  far as im aware, products containing chlorine (bleach) are no good for pressure washers as it can damage the seals but not sure about  products containing Benzalkonium chloride or DDAC (hopefully someone with better chemistry knowledge can differentiate between chlorine and chloride!).

Does anyone have any advice on whether either can be used from a domestic pressure washer without damaging it?

I found this info to suggest that Bac 50 might be okay to use through the machine.

Any advice welcome

p.s ive got an access tower so ill be working from the roof line so the low pressure setting should be enough to reach the ridge (about 4.5 metres).

[Mike Halliday]

The dilution of quats is so low it won’t effect the pump, but you will use far too much chemical and have massive drift and overspray using a pressure washer

[Splash & dash]

A pressure washer isn’t an appropriate way to apply bio or any other chemical  far to much mist spray drifting everywhere.

[Boba80]

Thanks guys for the replies.

Good to know it wont damage the machine.

I tested the variable lance  with an extension using  plain water on the lowest pressure setting  and didn't get any fine spray/mist, just a coarse spray....
I guess  mist/overspray is much more likely at roof level with the additional breeze and product solution as it foams up when mixed.

Maybe my approach isn't so great then......
might have to get the cat ladder out and do something different

[Mike Halliday]

I’ve re-read your first post and I missed where you say you will be using it from a scaffold at roofline level, from this close and with a lance long enough you could cut down the drift and over spray  so it could work with a big jet so you get a big droplet size but I think you will still use way too much solution.

I’ve used an X-jet to apply biocide off a ladder to a roof it worked but I’ll never do it again.

[Smudger]

we use the pressure washer to treat with biocide all the time - I use a downstream mixer ( like the x-jet ) and various nozzle on low pressure - no issues with drift or overspray

Just sharing my experience

Darran