Surface cleaning limestone?

Here’s my next project…

It’s definitely limestone so I’m assuming the nozzles on my surface cleaner will have to be swapped but what pressure is safe on this stuff? Right now I’m running 8/2500 at the wand.

I’m also assuming some SH will have to be laid down first, but this is a high end patio and I can’t have this turning weird colors.


Also doing this but I may have a decent handle on the fireplace.


Jumping in the deep end bud. Good on you :+1:

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I think you’ll be just fine on this project. Take plenty of before pictures because this will turn out nice when done. I would avoid any bleach on the limestone. Start with just plain water initially. I’d start around 1k-1.2k pressure. If you’re still left with staining, check out Sure Klean 942. Works really well for non polished stone.

Like you said, the fireplace is easy peasy.

Upsell sealing for sure on this. Siloxane PD or Natural Stone Treatment.


We’ve used Prosoco products with good results, but the cost is too high to sell… definitely when you’re working with 300+ linear ft of walls. Honestly, I’ve had better results with SH.

Here’s a sample where the stone shifts color when you apply SH, gave it a small dwell time, rinsed & repeat till the mold is gone. *This job the stone is 30+ years, never cleaned before


Prosoco works pretty good, I try to avoid SH if I can.

Used heat and under 1400 psi


Rub it in man.:laughing:

Why do you and @Historic avoid SH?

Living in Kentucky this state is full of limestone. I’ve been on many jobs people have called and said their rock or laid limestone has turned colors sometime after having it cleaned, what should I do. If I do use SH I have acid on hand to apply after using SH. Just personal preference, SH isn’t the cure all fo all surfaces. Most limestone I clean are on million dollar plus homes. Not throwing bleach on that. OneRestore works good too on limestone, Prosoco has several lines of chems too. I charge accordingly and explain to the customer, don’t really have an issue with it, they understand. I just sell our services and great chemicals help that.


I avoid SH on limestone because being so porous, limestone absorbs the SH and eventually crystallizes within the stone. This can cause future discoloration and/or complete degradation of the stone that would often be confused or misdiagnosed in the future when repairs are needed again. I opt for specialty chems and educate my customers why I use them. It costs more, sure, but peace of mind and longevity of service life is a ‘value’ to customers over ‘savings’.


Thanks for your responses guys. I’ll have to look more into it. Plenty of limestone around here too which is why I’m always interested in it.

Seems like saying throwing bleach on it gives it an extra negative connotation :joy:. Throwing hydrochloric acid on a million dollar home doesn’t sound pleasant either, but that’s in onerestore.

Not saying it sounds negative, but would rather use chemicals made to clean and restore limestone. Considering they have a million dollar plus home , I want to give the homeowner quality chems and no chance of destroying their property. I’ve seen it first hand, believe me. These homeowners don’t bring their Mercedes to Walmart for oil changes :wink: they pay 4 times the amount at their dealership, there’s a reason why. Just educate the customer, not a problem, they get it, their used to it.


So to be clear, can I use my 4 nozzle surface cleaner on the patio (it’s large) using ~1200psi? The calculator shows I’d need 25035 nozzles.

Here’s after hitting it with 1200psi nozzle, no chems. Hardly made a dent.

I believe it’s generally going to take both light pressure and chems. I know @Kentucky1234 has had luck with heat and pressure only though.

Hit it with about a 2-3 % mix. you’re better off surface cleaning it.


You can use a surface cleaner, just be careful with the pressure. Limestone is a soft stone. Just keep eye on it. Heat helps.

Do as mentioned above… hit it with 3-6% max (no surfactants), surface clean, rinse & repeat if need be…It’s important to mist the stone before applying the detergent, don’t soak it… Always, always…rinse out the detergent.

Got it, thanks guys.

After talking things over with the customer there is now some question if it’s actually limestone at all. The ‘stone’ does have saw marks but unlike the 100 year old front porch where you can see little shells in the rock, this stuff is perfectly uniform with zero ‘naturalness’ to it.

I did try a 50/50 mix and 10 minute dwell on one square, turned it a tan color but still blotchy.