Concrete overlay question

[opsh8r]

Hello to all, I'm new to this forum. My girlfriend wants to acid stain our house concrete slab (indoor, all bedrooms), but I'm having a problem adequately removing all the paint and stains on the concrete left by previous owners. I'm curious if any of you have done a concrete overlay. I've seen some microfinish stuff on the internet, but everything I've found is contractor-related, not DIY. Have any of you done an overlay yourself, and if you have what did you use? I tried searching the forum before posting but my searches only came up with contractor stuff. Thank you in advance for any advice.


Paul

 

[Jon]

This what you are looking for?
Someone just sent me the link but I don't know if it works, available, cost etc

 

[opsh8r]

That might be an option for us. My problem is that I can't get the original floor clean enough to apply either that type of floor or the acid stain. I believe before I can put down the stain in the video or the acid stain it might be easier to overlay the concrete. That part is what I am looking for advice on.

 

[Jon]

You might need a shot blaster as per video or maybe you could hire a diamond grinder with a vacuum to clean up the floor?

 

[opsh8r]

I am considering renting something like the shot blaster or maybe a large grinder/sander. I am also trying to find the overlay stuff so I can do a cost comparison to see which is cheapest/easiest to do. I'm also trying to research the overly in case I can't completely remove the stains from the concrete. If that is the case then I will have to go with an overlay.

 

[Jon]

If you use U tube to look at that video it gives you links to products you could use maybe
Being from New Zealand I am not really much help with products for you
Don't know where your fellow country men are hiding?

 

[Ernesto]

I've been to a class on overlays and acid stain. One way to clean the slab up is to acid wash it. Very toxic and dangerous, as even the acid stain is nasty.
I'd rent a diamond grinder from HD or the ones here have a diamabrush to clean it up fast.
One thing about staining is that you can't use patch for cracks because it won't take stain the same way as the concrete. But if the cracks move under a topping it will show just the same just not as ugly.
Also you don't want to take off the top layer of carbonated concrete if staining or else it will look like terrazzo in spots.
Out of all of the coatings I like the colored epoxy ones best.

 

[DennisT]

I've wondered about using a grinder - wouldn't staining look different in areas that were ground vs those that weren't?

It seems that if one wanted a uniform look the best would be to shot blast the entire thing to get a consistent surface.

 

[Incognito]

Hello to all, I'm new to this forum. My girlfriend wants to acid stain our house concrete slab (indoor, all bedrooms), but I'm having a problem adequately removing all the paint and stains on the concrete left by previous owners. I'm curious if any of you have done a concrete overlay. I've seen some microfinish stuff on the internet, but everything I've found is contractor-related, not DIY. Have any of you done an overlay yourself, and if you have what did you use? I tried searching the forum before posting but my searches only came up with contractor stuff. Thank you in advance for any advice.


Paul

Hi Paul.

I went to an Ardex Overlay Training along with their Moisture Barrier Systems. You know why they do both at the same time? Because you pretty much will always need the moisture retarder systems of some sort under any kind of topping over concrete slabs that set on or below grade. Grade refers to the level of the dirt outside your house. Unless the slab is up off the dirt/earth in some kind of foundation the moisture from the rain/landscaping pretty much always finds a way into your home THROUGH the concrete------believe it or not.

Truth be told nowadays with the newfangled chemistry of our industry without an effective moisture barrier there are very few choices for a quality flooring that would come with a warranty.

THAT'S why the concrete sealing, staining, painting and polishing alternatives are becoming so popular. People tend to assume it's going to be cheap and easy. HA! As our industry stumbles through this transition innocent customers and sleazy dealers will do all kinds of cockeyed, crazy stuff thinking it will work.

So, back to the particulars. I've seen the acid etching done only on new slabs. So I'm not familiar with the techniques needed to remove existing defects in old concrete slabs. Shot blasting is usually necessary for moisture barriers. You can't stain over the floor just like that afterward. You will need to smooth that with patch or overlay of some sort. Grinding could theoretically take defects out to achieve an even stain but I wouldn't consider trying that with a typical 7"-9" hand grinder. You would need something MUCH larger that's called a "planetary" grinder or terrazzo grinder. Here's what that looks like:

https://www.google.com/search?q=ter...ChMIzaKF553PyAIVixaUCh0yzQ5T&biw=1186&bih=576

 

[havasu]

Since I'm getting ready to epoxy my garage, I wonder what someone would charge me to grind down a 2 car garage?

 

[Ernesto]

Hav, out here the guys usually just do a light acid wash prior to coating the floor. The epoxy bonds pretty good just because a typical garage floor is broom finished so it ain't slippery.

 

[havasu]

The kits also come with a citrus acid, so it doesn't hurt house plants, but we all know how strong that stuff is.

 

[frostyfloor]

What's the ph of the floor? Why acid wash if you don't need too? A Light wash could just be diluted white vinegar if the ph is right.

 

[havasu]

What does ph have to do with epoxy bonding?

 

[DarisMulkin]

What does ph have to do with epoxy bonding?

High pH eats up most whatever is applied to concrete. If there is high pH there generally is a moisture issue also. Moisture pushes pH.

Daris

 

[havasu]

I didn't know that. Thanks buddy.

 

[Incognito]

High pH eats up most whatever is applied to concrete. If there is high pH there generally is a moisture issue also. Moisture pushes pH.

Daris

Right Daris, pH is an indication of moisture passing through a slab that has high alkaline salts so it's DOUBLE TROUBLE. Just the moisture alone could cause some bonding issues. Compound that with high pH and it's pretty much a high risk installation.

So for my kind of work----resilient---you need to test for pH and moisture to get an accurate read of what you're up against because the various remediation methods can get really extreme as far as time and money.

For modest levels of moisture and alkalinity we go with the 2% vinegar in warm water rinse and that's a done deal once allowed to dry. Higher levels push up the need for deeper sealing. The pH is a problem on the surface immediately as far as the bond but it's easy to fix temporarily. If you have high moisture and high alkalinity you really want to consider moisture barriers if you want the new flooring to last 10-25 years.

 

[Ernesto]

Here's a hot one that will make you cringe.

 

[Ernesto]

Check these out.

 

[Incognito]

I though Arizona was desert. How could you possibly have moisture failures in flooring?

yes, I'm kidding

Los Angles and the vast majority of SoCal sets on dessert and it's the worst cases imaginable because GCs tool zero precautions pouring concrete for multiple generations

now they want water based glue and plastic floors

that don't work