1st building wash. How much bleach do I need?

Hi ya’ll! I’m doing my first building wash, touch up really; next week. It’s a long drive so I don’t want to come unprepared.

The total square footage of wall area is about 12,260. It’s dark black mold growth in limestone. I’m only washing within the areas outlined by the client.

I have a 5.5gpm (about 4.5gpm with gun) softwash pump with 15 gallon tank.

I want to use 6% but idk if it will be string enough to melt away the dirt so I can just rinse. Should I just use straight bleach? Obviously this affects how much I should buy. Currently planning on buying 40 gallons to batch mix 5 tanks worth of 6.25%. About 20 minutes of spray time.

In testing I washed my neighbors driveway for her. I mixed a 5 gallon bucket with 2 gallons of bleach and 2 gallons warm water with 4oz soap. (Note this bleach is old. From early 2023). I was alarmed how quickly I ran out the bucket. Had to add another 2 gallons to coat the entire driveway, but the diluted parts were on cleaner areas. Put my strongest mix on the worst spots. It dwelled for 20 minutes, with intermittent wetting to prevent drying.

It didn’t melt anything away. Dirt came offnwith surface cleaner well enough but the green organics faintly remain. I will post treat when I get more bleach. She was kind enough to lend me her dirty driveway to experiment on.

Initial pics

15-20minutes into dwell time

After shots. Most came off but the growth remains.

Softwash system:

Just running water here. Can shoot fairly high vertically.

TBH sounds like you’re not really sure what to do. I’d down stream your normal house wash mix and wash with mild pressure. That’s just me. Be careful with limestone you may want to neutralize the sh. I’d do a lot more research if I were you.

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What I want to do is spray batch mixed bleach of sufficient strength (6%) to melt away dark black mold with the soft wash pump I made. I’m not sure however of just how much bleach a job like this would take since I’ve never done building washes of any kind before.

If this was a more than one time thing I’d modify my rig to have a 50 gallon bleach tank, 5gallon soap tank and proportioner system. Right now the margins to make that investment isn’t there. So I’m just trying to figure out how much bleach I should bring to batch mix. Hopefully it leads to more building washes where I can invest in that equipment.

You’d be amazed what a regular house wash mix and patience can do. I used to swear by my soft wash. I hardly touch it now. Downstream some house wash mix and give it a solid 15 minutes or so. Spray it and go back in the truck and watch the clock and don’t get impatient. You’ll clean it with medium pressure. I know you’re probably excited and anxious to try your new set up but 6% is way too strong. It’ll clean it but you’ll be wasting product.


Will do! So 1.5%?

I have yet to encounter limestone, but everything I’ve read about it suggests at least 4-5%

That’s what I’ve been reading too. Never hurts to start low though.

This guy used 5% on a limestone retaining wall around 25 minutes in. Good watch btw.

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Split the difference and go 3%, though on a lot of that looks like HW would do it. A few places you may need to hit with the 3% a couple of times

I wouldn’t go to a store without even checking my system while on the job site. First two things I would check are the line and the nozzles. I’ve had clogged nozzles several times, keep spares on the rig. I would also like to know how he knows this is limestone and not some other fake stone or veneer. This is why I don’t put much trust in youtube videos, they spout much without proof. besides, I’d have to drive at least 2 hours to get to the closest store.

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This guy is a lot more interested in his internet marketing than power washing. I don’t like bashing but you need a little common sense doing this. Why would you go do a huge concrete drive w/o any spare tips and then when it quit at least take them off and check? And sure, you can always hit something with stronger than you need when using SH. That drive wasn’t even that dirty. Would have done that whole thing with a hw mix. Same on that wall. And he’s telling everyone he made $250/hour. Right, how about 3 trips to property and back, wasting a day going to store, not to mention how much SH he used, labor, etc. I doubt he made $50/hr.


it’s all in how you work the accounting…


May do that. Would certainly save money on bleach. Removed my tool box. For this job at least I’ll keep my pump and battery here. (In the truck bed for transport. Just throwing it on here during the job. Plan to get a metal tool box to put the battery in, mount a proportioner and hose reel on eventually. What size bleach tank would you recommend? I have the extra 35 gallon tank in case batch mixing every 15 gallons becomes a pain. Got some pipe to hold down the hose. This is my very ghetto rigged version.

I have an estimate tomorrow to do exterior building washes for an apartment complex. Its a mix of 2, 3 and even 4 story buildings. 13 in total. If I get this bid I’d like to invest in a new 7gpm pump and large bleach tank.

what injector do you have to downstream?

Maybe he’s adhd (I have it myself), however I agree with you completely though. I keep a toolbox in the back seat with extra fittings, orings, wrenches. Maybe some of the drama is faked for views, who knows these days. To be honest though the channel does probably get him business with google algorithms and having a face and voice for the customer to see.

One thing I keep seeing popup on youtube now that kind of annoys me is the clickbait titles with the “big money” you can make in pressure washing ($3500 in day or $100,000 a month). This youtuber I posted earlier seems to show more of the day to day frustrations of running a pressure washing business (even the self inflicted stuff like the surface cleaner. We all make dumb mistakes now and then).

I also think a lot of the bigger ones have alternate sources of income beyond pressure washing. Its easy to dump thousands of dollars into equipment if you have real estate income or trust fund money. Not that I’m knocking anyone for having that, I think its great, wish I had that. My complaint is they give a false sense of ease to getting into this business from a comfortable financial starting point.

I mowed lawns to buy small time equipment and eventually took a loan to get the rig to do commercial work. Im not make 6 figures yet but I can pay the bills. After grinding for 3 years I’m starting to get traction. This estimate tomorrow is a result of me doing breezeways at another property of theirs. It’ll be pretty big ticket compared to my other jobs, so I’m excited (trying not to count the chickens before they hatch but have to be hopeful). Anyway its a long grind to get successful in this business and I wish more youtubers showed that.

That’s the end of my rant. Didn’t intend for it but sometimes it is what it is.

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This one. It came with the rig. I had a 35 gallon tank of degreaser that the seller so generously added on for “free”. Still have 15 gallons left since getting it at end of 2022. At 7.5-8gpm it doesn’t draw a lot of chemical.

I’d recommend knowing what you’re using, or buying new ones so you do… at any rate, you should have at least 1 more of “that one”, lol

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Agreed. I just use it so infrequently except putting degreaser on dumpsters that I’ve never given much thought to it until now. I wanted to downstream for this job but according to what I’ve read even with the best injectors I couldn’t get a high enough mix with 8gpm to treat really set in black mold. I’d welcome any suggestions for injectors though. Always good to have more tools.

We all make mistakes and do dumb stuff. At least once/day, lol. But don’t sit there and say I only made $250/hour. And you’re right on the clickbait stuff. Sucks a lot of people in, who then spend a lot of money on equipment and then screw up market.


How do you wash houses?

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I haven’t washed any homes yet. I’ve had a few estimates but no takers. My work has basically been strictly subcontractor commercial work for shopping centers and apartments. I watch my kids most of the day so it’s difficult to grind for business. Subcontracting pays less but I have steady business from the parent company. I still put my own bids out but no success thus far. When I have more time when the kids are in school I’ll be able to more bids. I drive to areas that look dirty, take some photos, draw up a proposal and call/email the property management.

Loaded for my soft wash batch mixing adventure tonight. 16 gallons of bleach.

On a separate note, what do you think of Gold Assassin degreaser? Kept seeing youtubers push it and seems to work well. Distributor was sketch as hell though. Went down like a drug deal. Buying it out of a truck in a industrial parking lot. Cash or zelle only because people would cancel the credit payments apparently.