What questions to ask before washing a house

Hello everyone I have been lurking here for a while most time has been spent logged out of my account since I mainly just read for the most part anyways but what questions can be asked before a house wash I know most stay away from hardy board and aluminum sided houses

And red blue green and brown vinyl as well as the same for painted hardy etc…

What questions does one ask is it simple as what type of siding do you have and what color is it or is there also questions about the type of widow frames or the color of the shutters if they have been painted enough or what type of plants or deck they have … just looking for what info is needed to vet out and houses that should be walked away from

Thanks everyone have a blessed day

If you have the address, you can look it all over pretty well on Google maps between the 3D satellite and street view. You can see the size, shape, what type of siding, color, everything. I have never found a reason to avoid any color hardy board. I’ve done them all, red, blue, green brown. I just use a much lighter mix( ~0.3%), don’t let it dwell as long and rinse a whole lot more than I do with vinyl. Once you think it’s rinsed good, do it one more time. They take about 20 minutes longer with all the extra rinsing, but I charge accordingly. Those that turn down every hardy house or odd colors just have plenty of other work that they don’t need to worry about it. I’ve been at this for going on 5 years and have never turned down a house and never had any issues with any of them.

You do need to be careful about some paints like Sherwin Williams that has organics in the paint. I’ve personally never ran across this, but they will change colors with bleach. Most houses you can tell if shutters or doors have been recently repainted or if they are original. If you are unsure, always do a small test spot or avoid all together if possible. Most front doors I only hit with water just to be sure.

Thanks for the response yeah I’ve heard to lower sh down to .5 or so would help out does going that low clean the soffits and gutter though. Also is this what you do on vinyl dark colored siding as well ? And does it still clean

Aluminum has never been an issue for us in itself (although be more keenly aware of oxidation on aluminum, and cut your SH 50-70% what you’d normally use), but always do a test spot for the old “organics in paint” issue. We’ve run into that on both Hardie and aluminum sidings. Darker vinyl is generally “business as usual” for us, but definitely be more aware of keeping it wet for sure. Also, I think on darker surfaces quality of rinse water can be much more of a concern.

My go to for 90% of houses is 0.6%. I know at this ratio I’ll get the algae off and don’t have to worry about grass or plants too much. I rinse plants after, but I don’t need to water anything down beforehand. I always like to hit each area twice just to make sure I hit every square inch. If a side is really bad, I go 1% but make sure I water before and after. I prefer to be overly cautious. For houses that are only dirty (not much algae) or are dark colors / hardy board, I go down to 0.3%.

Many guys on here don’t worry about exact percentages and just say if it turns brown in a few minutes you’re good to go. I’m that guy that likes to know exactly what percentage I’m spraying because I know how it reacts with plants and certain types of siding. I also like managing exactly how much SH I use on houses. I know within ½ gal how much I’ll go through with each one of those percentages. It helps be better plan since I’m part time and don’t buy or carry bulk amounts with me.

For gutters that are really bad, I just take a brush to them. I’ve found that much faster than hitting them a multiple times. I have a brush on a 8’-24’ extension pole. Usually they don’t need scrubbed, just walking along one time with a brush is typically enough. I carry that brush as well as one on a 4’-8’ pole. They are like condoms, it’s better to have them and not need them, then need them and not have them.

How are you metering that precisely?

The gun I use has metered orifices that range from 5:1 on up and comes with about 20 different ratios. I’ve tested them at my normal pressure to verify they are right on.

Oh gotcha, so you carry around a pail?

Nope, it comes with a cap that attaches to gallon jugs. I use straight 12.5% and elemonator in them and use 2.5-3 per house. I have a 2.5 gallon jug with a bulkhead fitting as well, but it’s too heavy to lug around houses. I use it for flat work since I’m not walking around as much and tend to use more for pre and post treating.

1 Like

So if I cut my 10percent sh in half and ds at 10-1 I’ll get roughly .5 percent sh … now if I pre wet as some suggest on darker homes would the sh still kill the mildew ?

Yes, it will.

1 Like

As @qons said above, yes it will kill the mildew. But, depending on the amount of build-up, you may have to spray that area 2 or 3 times, which adds another 5-10 minutes of dwell time depending on how you do things. If you’re finding that the first application of mix didn’t make the mildew disappear, apply a second/third coat of mix BEFORE you rinse.

1 Like

So is .5 percent a safe percent to use on hardy and vinyl of the darker colors just have to keep wet and do more passes and a little longer wash time … thanks for the tips guys

I can assure you that you will never know if it’s 0.5 or .9 without lab testing the SH for strength prior to using. Anyone rounding anything with SH that starts with 0. Is in micky mouse land. TARGETS of 1% 3% and 6% will clean anything Mother Nature presents you. These are the only targets that matter on my proportioners.


What’s your experience with 1percent of those colors ? Or do you not wash them ?

If a house doesn’t have much algae on it, why would I use 1% and not 0.3%? No point in throwing away money in SH when I simply have to change metering tips that only takes seconds. It may only be saving $5 per job, but over a year that can be a good saving for just knowing your ratios and what it takes to do that particular job. Maybe I don’t know the exact SH composition, but I know what tip works best in what conditions, so I choose accordingly.

How do you test your SH? How do you come to the conclusion that your starting base is what’s written in the container? What test gives you this base to work off of to be able to fine tune any given decimal point?

Like I said, doesn’t matter what the actual percentage is, just that it’s consistent. I know what ratio just works best for the condition and adjust for jobs that need it. I’m at 19:1 for most houses, 12:1 if they are bad. What actual % that is really doesn’t matter, I just estimate 0.6 and 1%, but clearly that’s not exact and rounded.

I think you guys are saying the same thing, lol

He agrees with me, he just doesn’t want it in writing lol