Limestone Restoration on a Stadium

Finished up a job this week on a stadium! I did not measure out all the limestone, but I would guess between 75K-100K sq ft. It is everywhere in this place, including the parking lot!


Had to mute it - but awesome work! Looks new again :slight_smile:

The retention walls are the money shots !

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Good work. Lose the music on the video though.

Looks good, made me want a beer and crank megadeath…

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Btw I love the music choice!

Looks great, would you mind sharing your process. I tend to shy away limestone, but have seen people like yourself have great success.

Great work! How long did it take you to complete? What equipment / Chemicals did you use and did you have help or were you flying solo?

I was going solo on the job.

I originally bid this job over 6 months ago. At that time, I had done 4-5 limestone type jobs that were residential size. Between the time I bid the stadium and when it was approved, I had done 5-6 larger commercial jobs and knew when I started the stadium that I had underbid the price and time needed to complete. When you do smaller jobs and your estimate is off a bit, you don’t really notice it much. Say a house wash that you think is 2 hours but takes 2 hours 20 minutes. Not a big deal. When you scale that to a job like this stadium, it is a big deal.
I originally projected 9 days to complete the job. It ended up taking 13 days.

The thing I have learned about limestone, it is a bit of a crap shoot. In my area, rarely is it a pressure wash situation. The mold gets deep in the pores and it can take 2,3,4 even 5 applications to kill it all. You just do not know until you start doing the work. In some areas, what I though would take 1 day did take a day. Other areas I thought would take a day ended up take 2 days.

My rig is a 8gpm hot water skid. Doesn’t really matter though (other than rinsing). Once you get the surface funk off, it is a chemical and rinse game. I do have a 12v - 2.3 gpm soft wash set-up just for chem application. I am done with pump-ups for anything other than very small or spot type stuff. I also have a traditional 7 gpm pump for roofs. I have the two pumps side by side and “t” the supply like with a 3 way ball valve so I can easily switch from one to the other using the same battery, water supply and chem supply with a DIY proportioner.


Alkaline then acid ? or alkaline & warm, hot water ? Details man details…

So are you pressure washing it first then going back with chemical pump? Are you downstreaming with the pressure washer? Really interested in figuring out limestone. - Thanks

Here’s a link to a website that @Racer posted awhile back on cleaning historic buildings. If you scroll down you’ll see a section about limestone. There’s also a ton of other useful information.

Here’s another thread where Rick gives the process for cleaning limestone. It’s definitely worth looking over.


With over 1 million sq ft last year of just this type of cleaning here is what I would do.

  1. Mid-pressure wash. Knock off all the surface mold.
  2. Apply a 4% solution via direct chem pump or hand-held pump up.
  3. Dwell 5 min - reaaply.
  4. Rinse.
  5. So steps 2-4 over and over and over until it comes clean. You can increase your SH % but I never go beyond 5-6%.

Here is what you got. Mold works it way into the pores of the stone. The initial cleaning gets the surface crap off, but leaves a gray stone behind. You have to apply chem over and over until it soaks into the pores, kills the mold and you can rinse it off. Sometimes this results in oranging of the color of the stone, but it generally goes away after a few months but not always 100%. I did a dentist office and oranged the crap out of it and 6 months later is looks fairly normal. I know the SH reacts to the iron minerals in the stone which causes the oranging but I can explain why it goes away after awhile.

Proof of my work: Limestone Restoration on a Stadium