Pressure Washing Concrete ??

[billt]

Now that I've had this new concrete work done, I'd like to clean the older portion of my driveway. It's 20 years old, and has gotten yellow, dirty, and dingy over time. Not to mention when they excavated for my new concrete the Bobcat driver got rubber tire tracks all over it.

I was thinking about renting a gas powered pressure washer from Home Depot. They run only $50.00 or $60.00 bucks for a 4 hour minimum with a $100.00 deposit. Which seems really reasonable compared to hiring it out.

Have any of you guys ever done this? I've watched videos on You Tube, and it's amazing how well it works. I would like to not have to mess around with chemicals or cleaners. My driveway doesn't have any oil stains. Just the tire tracks, along with 20 years of dirt and grime.

[alfack]

I do it every spring to my driveway. It accumulates dirt and algae like moss slime, from all the rain. I broke down and bought a gas powered one from Costco several years ago, after my electric Karcher died. Good investment.

[Rastus]

Oh absolutely I've done that.  A lot of it.  Absolutely do not go less than 2,400 psig discharge.  2,700 is pretty good.  I have one that does 2-1/2 gallons a minute at 3,200 psig which is a very big improvement over 2,400.

Below 2,400 it is more a tease than a workhorse.  To do a really good job wet the concrete down and then take some cheap bleach  and spread it out with a push broom and let it work 10-20 minutes keeping it wet the entire time.  Then pressure wash it all.  Check the % of sodium hypochlorite; cheap sometimes has 6% vs 4% in name brands ( That change of 2% is really 50% more active ingredient).

Note what your faucet provides for water volume.  The 3,200 psig unit I have needs 5 gallons a minute...twice what it pumps.  It needs that so the pump is not starved on the suction side...which will tear a pump up sooner or later.  You may need to time a 5 gallon bucket.  Those little 3/8" water hoses won't work...you need a 3/4" if you can get it.

You can buy a good one for normal light use around $300-350.  Wash your car with it, the house, car mats, ash trays, rugs, strip paint, etc...whatever. 

[Big Frank]

You may want to buy one instead of renting, but renting would be a good way to see if it's something you'll want to do enough to justify buying one.

[billt]

You may want to buy one instead of renting, but renting would be a good way to see if it's something you'll want to do enough to justify buying one.

I would buy one in a heartbeat if I had a place to put it. After I get some of my new driveway block walled and gated in, I'm going to put up a nice small storage shed. Then I'll get one for certain. Right now I lack the room.

[Sponsor]

[TAB]

Most places also rent a surface  cleaning head.  Which is well worth the money.   It will go faster, you will stay drier and it will prevent damage too the concrete. 

[alfack]

Most places also rent a surface  cleaning head.  Which is well worth the money.   It will go faster, you will stay drier and it will prevent damage too the concrete.

+1 to this idea. Makes it a much quicker job.

[billt]

Most places also rent a surface  cleaning head.  Which is well worth the money.   It will go faster, you will stay drier and it will prevent damage too the concrete.

I saw those on You Tube. But the Home Depot by me doesn't have any available for rent. I'll try a few others in the area. Are these the things that look like those big floor buffers you see janitors pushing around on hospital floors?

[TAB]

Yes, they have like a whirlybird sprinkler

[MikeBjerum]

I have run pressure washers for years in our barns.  Volume is as important as pressure, but for what you are doing, or will in a home setting, 3,000 psi and 2.5 gpm is plenty.  It may take longer for some tasks, but no reason doubling the price of equipment.

For cleaning the concrete, my years in the service station and auto shops made me a fan of powdered Tide.  Wet the surface, sprinkle the tide on the surface, and scrub with a stiff push broom to work in, DON'T LET IT DRY as it soaks, and then blast off.  In the service stations we only used faucet pressure through a nozzle.  However, it works quicker, and better, with the pressure.

Have fun!