Old concrete

[FlaSteve 1]

Hello All.

My South Florida, concrete, three car driveway, is now twenty five years old, and looks it.   After all the twice a year cleaning, the concrete is somewhat pitted.  My usual session is no longer removing, what I guess to be, a build up of dirt and grime in the pits.  I have only used my rig (DeWalt 4200 psi, 4 gpm pressure washer, and AP+ 21" surface washer) to this point.  I never got in to pretreating, or using detergent.  That's due to the various, and often conflicting recommendations, that I've read each time I've researched.  I never came to a workable conclusion in my mind.

I'd greatly appreciate a coherent solution, from a knowledgeable person, if you have the time, and thanks in advance.  I'd like to read a  full description of what I should do at this point.  Specific equipment.  Detergents and pretreatments.  And method and technique.  I'f needed I'll purchase a downstream injector and the like. 

Cleaning twice a year is enough, the last cleaning stayed just four months.

Thanks,

Steve

[Beth n Rod 1,279]

Hi Steve.
Cleaning concrete driveways works best when adding cleaners to address the stains specifically. For overall dirt and grime, a degreaser and bleach do the trick.
For leaf stains alone, a mild oxalic acid after prewetting helps to lighten them if you are spot treating. Otherwise, increase the strength of the bleach and possibly
apply by using a pump up sprayer to focus on the dirtiest areas.
A surface cleaner helps because it uses a rotating bar to spin and clean much more surface than a wand can cover. It's not about the pressure, it's about the method and the cleaners.
Let me know if you have any further questions or would like to add specifics on what the stain(s) are composed of that are not coming out.

Rod

[ssanderz30 2]

I think you should to combine different paver sealers at the same time, and check it out.

Edited December 25, 2019 by ssanderz30