Question:
Our home has stains on concrete from pots and other things. The stains
are on the driveway, in front of main entrance door and back patio.
I was told that pressure cleaning might loosen the very tiny pebbles on
the concrete or damage the concrete.
Is there an easy and economical way to get these out ?
Any other ideas ?
Has any one any experience in removing such stains ?
Answer:
Stains from pots on the driveway? ...Okaa-ay...
I have an electric pressure washer (1200psi, IIRC) and it does just
fine on sidewalks and driveways without damaging them.
If you're worried about an bigger, industrial strength washer damaging
it, just rig up a spacer to keep the nozzle further away from the
surface. That will effectively lower the pressure.
So now you've been told that it's not ok and you've been told that it's ok.
For once, I actually agree with Don K. I don't think that the home pressure
washers will be powerful enough to even think about damaging the concrete.
I would think that you would need to get into the 4,000 PSI range to even
think about doing any damage.
But then again, your big commercial washers are 4,000PSI and up and I have
never seen damage to concrete or asphalt buy using one of them....
Depends on the stain. Some stains may not come out.
Kitty litter and solvent- kerosene/naptha for oil. Some people
substitute wood shavings or sawdust for kitty litter.
Acid wash - the standard for cleaning grout and some concrete stains.
Use muriatic acid from a pool store and dilute.
Chlorine - again from a pool store and put in a hose-end sprayer.
This is what is used to clean "kool-decks" and is very effective on
molds and common dirt. The trick is to treat the enitre surface.
TSP, tri-sodium phosphate is another cleaning standard. Follow the
dilution recommendations on the box.
Pressure washing. Can work without damaging the surface if low
pressure and hot water with a detergent are used.
The last building I worked in has a pattern of rings about 4" in diameter
etched into the surface of the sidewalks on one side of the building,
where someone used a pressure washer with a round nozzle to clean them.
The rings overlap, about 3/4" spacing. I'm sure that if the washer had been
held in one spot, it'd have dug a hole into the concrete.
