Is it a good idea to Pressure wash an old concrete driveway?

AprilSun

AprilSun

Senior Member
My concrete driveway is at least 42 years old and it is getting so black. I was just wondering if it was a good idea to pressure wash OLD concrete or will it cause damage because it is so old? If it's been done before, I can't remember it but I do know it hasn't been since my husband passed away. I will appreciate any advice out there.
 

If the concrete is in basically good shape...no big cracks, or surface pits, etc., a pressure washer shouldn't cause any problems. If there is a lot of "black"...from oil leaks, etc., you might want to treat the concrete with a good cleaner, first. Stores like Lowe's, or Home Depot, etc., sell cleaners that usually work pretty good.
 
Don M. said:
If the concrete is in basically good shape...no big cracks, or surface pits, etc., a pressure washer shouldn't cause any problems. If there is a lot of "black"...from oil leaks, etc., you might want to treat the concrete with a good cleaner, first. Stores like Lowe's, or Home Depot, etc., sell cleaners that usually work pretty good.
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It's not oil leaks but I'm wondering now if it's mold. It has been very wet here this spring and summer. As for if it's pitted, I don't know but it does have several cracks that are long. Should I forget the idea of pressure washing because of the cracks?
 

What about bleach ? I never tried it but I do that on our house siding that gets mildew from being under the tree. Works great and doesn't even fade the siding. You could try a small area. You probably have some bleach. If it works I'd use a bucket and an old mop and just slosh it on.
 
If it's black and not penetrating the concrete then it's mold.

It should be easy to clean with the same product used to remove moss from roofs and shingles.

You can pick it up at a garden store.

I doubt if a pressure washer alone can remove it. That's a living plant.
 
AprilSun said:
It's not oil leaks but I'm wondering now if it's mold. It has been very wet here this spring and summer. As for if it's pitted, I don't know but it does have several cracks that are long. Should I forget the idea of pressure washing because of the cracks?
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Water and cracked concrete driveways do not get along well. Most housing contractors just lay the concrete over plain dirt, and if the concrete is cracked, over time, the water will erode the base, and the cracks will only get bigger. Only driveways that have been laid over a good gravel base can survive for decades. Now, if you suspect that "mold" is the problem, Bleach is certainly a good option. We live in a humid climate, and mold on the house siding is always a bit of a problem. Every couple of years, I mix up a mixture of 1/3 bleach, liquid soap, and water, and spray the siding with my tank sprayer...leave it set for about 30 minutes, then hose it off with the garden hose. That usually does the trick.
 
Thank you Don for all your information and help. I haven't made a decision yet. I'm the type of person who will "do their homework" before I make a decision and that's what I'm doing now. Especially on something I know nothing about. The crack issue could be why my husband never did it because it looks like it would have gotten this way before since we've had it at least 42 years. Thanks again!
 
There are companies that do this; concrete / pavement cleaning. You could get a quote just to see if they would do it with the cracks (or how they propose to deal with them).
FYI; I recently learned that there are power washer attachments that makes this a lot easier and faster; the Homelite EZ Clean is one of them.
 
If it's mold or moss and you power wash it off it will just come back.

Mold and moss are living plants. You have to kill it first. They penetrate right into the pores.

If you use a mold or moss cleaner on it you will be amazed at how it flakes right off. You can hose it off with a garden hose.
 
HipGnosis said:
There are companies that do this; concrete / pavement cleaning. You could get a quote just to see if they would do it with the cracks (or how they propose to deal with them).

I have thought about getting someone to do it but I have friends and a brother that could also do it if and when I decide.

FYI; I recently learned that there are power washer attachments that makes this a lot easier and faster; the Homelite EZ Clean is one of them.
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Camper6 said:
If it's mold or moss and you power wash it off it will just come back.

Mold and moss are living plants. You have to kill it first. They penetrate right into the pores.

If you use a mold or moss cleaner on it you will be amazed at how it flakes right off. You can hose it off with a garden hose.
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I know it's not moss but I'm not sure if it's mold. It could just be dirt. I'm still in the "thinking stage" but I appreciate everyone's help!
 

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