Cleaning Concrete

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Posted: 5/28/2015 3:02:11 PM EDT

I have an enclosed patio (a sunroom). The slab is about 60 years old and has accumulated a lot of "scars" over those years - paint drips, blobs of caulk, urethane foam insulation stain, SLU droplets,... all kinds of stuff. I was never worried about these because they were covered by a big rug.

The problem is the dog keeps peeing on the rug and we had to take the rug out due to the smell (UGH!). We are working to retrain the dog, she's a very willing student but this is a long-standing bad habit we are trying to break.

In the mean time, we don't like the look of the messed up concrete.

How do we clean the concrete?

1. A pressure washer is probably out due to the over-spray and wet contamination of the book shelves and furniture that are out there.

2. A scrub brush and floor cleaner does not touch this stuff.

3. We considered tiling over it but want to explore less costly options before we commit to that.

Posted: 5/28/2015 3:09:00 PM EDT

[#1]

Paint over it.

Posted: 5/28/2015 3:54:17 PM EDT

[#2]

I've heard some people use muriatic acid to clean concrete driveways.
May be worth looking into.

Posted: 5/29/2015 5:52:44 PM EDT

[#3]

We absolutely are not going to paint over it.

The question is this, is there a way to clean it?

I thought muriatic acid cleaned/etched the bare concrete but did not get after the spills. Am I mistaken? If it weren't for the spills, we wouldn't need to clean it.

Posted: 5/29/2015 8:40:15 PM EDT

[#4]

You won't be able to clean all the way out to the edges, but ... If you get one of those rotary deck pressure cleaning attachments ...
and you're careful with it, you'll be pleasantly surprised at how little water flies around. As in, almost none.

Stay safe

Posted: 5/29/2015 11:55:39 PM EDT

[#5]

Quote History

Quoted:
... rotary deck pressure cleaning attachments ...

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I hate to have to ask dumb questions, but to what does it attach?

Posted: 5/30/2015 12:08:45 AM EDT

[#6]

The only options other than painting will get very expensive.

There's equipment that will take off the top layer of concrete and polish it.

Edit: you can't clean concrete.

Posted: 5/30/2015 1:51:51 AM EDT

[#7]

Are there no large scale flapper wheels or other abrasive method to scrub the entire surface, it's about 200 sq ft?

What is the attachment SparkyCG referred to?

Posted: 5/30/2015 10:51:44 PM EDT

[#8]

Try a belt sander with 60 grit.

Posted: 5/30/2015 10:56:38 PM EDT

[#9]

Quoted:

1. A pressure washer is probably out due to the over-spray and wet contamination of the book shelves and furniture that are out there.

View Quote

a pw will eat through concrete like butter too

Posted: 5/30/2015 11:58:54 PM EDT

[#10]

Muriatic Acid

Use it full strength. Make sure you have lots of windows open.

Posted: 5/31/2015 1:24:12 AM EDT

[#11]

Quote History

Quoted:
Muriatic Acid

Use it full strength. Make sure you have lots of windows open.

View Quote

Will it remove the paint, caulk, spackle and silicone? Will it remove the spilled urethane foam?

How do you remove the material and dispose of it after application?

Posted: 5/31/2015 7:59:08 AM EDT

[#12]

Quote History

Quoted:

I hate to have to ask dumb questions, but to what does it attach?

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View All Quotes

Quote History

Quoted:

Quoted:
... rotary deck pressure cleaning attachments ...

I hate to have to ask dumb questions, but to what does it attach?

A pressure washer. Up to about 3K pounds.
I reread your post and ... Can't imagine that job w/o removing the furniture and bookshelves.
IF you use the muriatic acid, for God's sake use a respirator and more ventilation than you think you need.

Stay safe

Posted: 5/31/2015 9:34:43 AM EDT

[#13]

We've had some success with a floor buffer and a screen pad. It's not a substitute for a floor grinder or shot blasting but with patience it will clean the "surface", not holes or inside corners, that's all hand work. Wet the floor, run buffer then vacuum the water with a shop vac and repeat.

One of these can help too- LINK

Posted: 5/31/2015 10:40:16 AM EDT

[#14]

If the concrete is urine saturated the only 'cure' is to seal it.

Epoxy floor finish works well.

Posted: 5/31/2015 10:15:35 PM EDT

[#15]

Quote History

Quoted:

Will it remove the paint, caulk, spackle and silicone? Will it remove the spilled urethane foam?

How do you remove the material and dispose of it after application?

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Muriatic Acid

Use it full strength. Make sure you have lots of windows open.

Will it remove the paint, caulk, spackle and silicone? Will it remove the spilled urethane foam?

How do you remove the material and dispose of it after application?

Purple Power works well to clean stains in concrete. It will fade oil and transmission fluid out considerably. The stain will still be there, but it wont stick out very much. You can mix it with water or use it straight.

Posted: 6/1/2015 1:21:03 AM EDT

[#16]

Quote History

Quoted:

A pressure washer. Up to about 3K pounds.
I reread your post and ... Can't imagine that job w/o removing the furniture and bookshelves.
IF you use the muriatic acid, for God's sake use a respirator and more ventilation than you think you need.

Stay safe

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
... rotary deck pressure cleaning attachments ...

I hate to have to ask dumb questions, but to what does it attach?

A pressure washer. Up to about 3K pounds.
I reread your post and ... Can't imagine that job w/o removing the furniture and bookshelves.
IF you use the muriatic acid, for God's sake use a respirator and more ventilation than you think you need.

Stay safe

I really cannot imagine using muriatic acid. The waste sounds almost like a "haz mat" situation. I'd have to titrate it or something to dispose of the waste.

It is just a concrete patio slab that abuts the house on two sides and is now screened in on the other two sides. There's plenty of natural ventilation and I have fans, but still ...

Posted: 6/4/2015 7:16:03 PM EDT

[#17]

I do architectural precast. Stains and discoloration are almost always impossible to remove but something that can sometimes work is soak the area in white vinegar and work it with a scrub brush. This does not always work and it does slightly etch the concrete surface but it is much gentler than most acids.

Posted: 6/7/2015 3:38:39 AM EDT

[#18]

He doesnt have stains - he has surface deposits that need to be removed.

Use a large metal scraper and a large wire brush. When done, seal it with a clear or colored epoxy.

Posted: 6/7/2015 8:46:36 AM EDT

[#19]

Is it smooth concrete, or broom finished? Smooth concrete can be lightly ground with a Diamabrush attachment on a floor buffer.

https://youtu.be/drgB7J-ckbA

Posted: 6/7/2015 10:58:22 AM EDT

[#20]

Quote History

Quoted:
He doesnt have stains - he has surface deposits that need to be removed.

Use a large metal scraper and a large wire brush. When done, seal it with a clear or colored epoxy.

View Quote

Just do NOT use a steel brush.
It will leave enough metal behind to produce rust stains.

A concrete grinder, but they use plenty of water also.
Remove everything you can from the area, tarp off the rest with heavy plastic.
Pressure wash carefully.

Posted: 6/7/2015 12:07:03 PM EDT

[#21]

Quote History

Quoted:
He doesnt have stains - he has surface deposits that need to be removed.

Use a large metal scraper and a large wire brush. When done, seal it with a clear or colored epoxy.

View Quote

The surface deposits cannot be scraped off. I've tried. In fact, most of the dropped materials were wiped off with a rag, leaving only a very thin layer - thinner than the surface roughness caused by the outermost layer of sand in the concrete. Remember, this is a 60 year old slab that spent many decades unprotected.

A wire wheel might get down in there but will almost certainly scar the surface. Still, it's probably better than paint residue.

I should take and post a photo.

Posted: 6/8/2015 2:59:38 AM EDT

[#22]

tile?

Posted: 6/10/2015 9:25:12 AM EDT

[#23]

Quote History

Quoted:

We absolutely are not going to paint over it.

The question is this, is there a way to clean it?

I thought muriatic acid cleaned/etched the bare concrete but did not get after the spills. Am I mistaken? If it weren't for the spills, we wouldn't need to clean it.

View Quote

Try a weaker acid like white vinegar. Use a scrub brush and go slowly, have a person with a towel policing up what runs off the spot you are working on. Try it on one of the stains, if it doesn't work, you'll get a different looking stain (probably lighter) and not really be out much.

Some stuff, you are not getting out of it period. Paint drops probably won't come out without removing material.

Is this a rental? Why can't you paint it?