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Chalking concrete

  • Thread starter Cass
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Cass

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I have a building that has a concrete floor that was poured with self-leveling soupy concrete with the result that the floor is constantly dusting with just foot traffic and routine carts. In one area I painted the floor with some garage floor paint and that helped but the soft surface of the concrete fails and the paint flakes up eventually. I wonder if anyone has a recommendation of some type of paint that is tougher or some other fix that doesn't cost a fortune.
 
I am looking at the various sealers. The floor paint I used before is a water based, epoxy strengthened product from Benjamin Moore which had all the various claims for sealing and strength. I am sure it would work well on a nominally hard concrete. A thick coat of 2 part epoxy with paint flakes in it etc. might hold together and it might not if the floor gives up. I am wary of the "soaks in" claims these products make. If something truly soaks in an strengthens the concrete it would logically be a good thing but I would have to see it to believe it at this point so I am looking for someone's hands on experience as a guide. I could put down vinyl tile or flooring but that gets expensive and takes a lot longer to do ....maybe.
 
Cass --

Your "Doesn't cost a fortune" criteria may contradict this suggestion, but an epoxy floor finish cut very substantially with alcohol will penetrate and firm-up spongy concrete.

I believe that the Foundation Service Company in Houston has a "white paper" on this very subject on their website. If not, it might be worth your while to give them a call.

John
 
I have a friend who watched them pour concrete out of a truck that had been sitting in his driveway for 2 hours. They added LOTS of water to make it easier to pour, which he took a few pictures of with his movie camera. Then they came back 3 days later and bricked in the walls and added the roof. He questioned them about the chalky dust, and they said it was normal and would stop in a few days. He told them he would pay them when it stopped.
They countered with a lawsuit, which they lost. He got the garage for the cost of missing a couple days work. To hear him tell, he would rather have paid for it and got a nice floor.
He sold the place before doing anything with it, so I am no help on that end.
David from jax
 
When you say "soft" and self-leveling, it sounds kind of like a product called Gyp-crete, which is a gypsum cement mix that was (haven't run across it for a while) used in the 80's for interior floors in offices and apartments to help with sound deadening, etc. Its major drawback was strength, and resistance to water. It could disintegrate if flooded or soaked, as might happen with a water heater breaking, etc.

There are many sealers on the market, from linseed oil to exotic epoxies, etc. There is a waterproofing product (can't remember the name) that goes on like water and soaks into the concrete to crystallize the structure and waterproof it, but I don't know if it will work with the gyp-crete.

Sounds like you need to get someone out there to ID your floor material and recommend a product to stop the chalking (if it can be stopped).
 
Nope, this is pure ole crappy concrete that had too much water added to make it easy to float. I'm sorry to say there's not much you can put on it except epoxy (over bear floor). If it's painted now, you'll have to strip it. DO NOT use water-based anything! Even if you tried to tile it, it would have to be sealed with epoxy first to get the tile to stick.

Did you have a contract that stipulated the PSI or "bag" mix? If not, tisk-tisk. If so, you can threaten the contractor with a lawsuit if it doesn't make spec. You would have to take a core in a couple of places and send it to be tested, with report.
 
Cass,

Go to a Sherwin-Williams store. They've got some pretty good floor products. We had a problem when I lived down there and I asked if one of their "field guys" could stop and look. He was there within a week and told us how to fix the problem.

JR
 
Don't ask us ignorant guys. You have a problem requiring expert advice.
Paint and sealers will not solve your problem. They will only prevent adhesion to products that may solve the problem.

There are trowel-on cement/fine aggregate product that leave a hard durable finish. If the concret underneath is weak and the subsoil settles permitting the cheap weak concrete to crack and subside you're screwed.

I suggest you contact a couple of concrete experts to examine your options. Ask about wear resistant top coatings. A lasting solution suitable for your crummy floor suitable for a home machine shop having heavy point loads will not me cheap.
 
It will NEVER change no matter what you do. Don't waste money on a sealer - when concrete has too much water in it, it simply never sets up (cures) right. The dust you have is simply portland cement particles that never bonded to the other ingredients in the mix. The extra water suspended them in the solution and prevented them from doing so.

REMEDY: Saw cut an acceptable perimeter and jack it out. Order some real concrete and tell them if its soup when it comes you'll send it back. Then, when it comes, dump an entire bag or two (96 lbs worth each) of Portland cement into the mixer and have them spin it until the mix is homogeneous before you pour it.

After you pour it and skreed it level with the top of the old stuff, then float it with a wooden float and then finish troweling it before it sets up. Hand sprinkle some MORE portland cement onto the surface as you float it.

Then put on some Ben-Gay and relax.

If you want a REAL seal on it, wait until a few weeks after it cures and wash it with a week Muriatic Acid wash. Then get a commercial, 2-part epoxy, and apply it yourself.

Than put on some more Ben-Gay and relax again.
 
Your bad surface will never be good. Use an air tool called a "bush hammer" to remove the bad top layer. You will know if you get to good material as it will be hard and strong. Clean with water and wet vaccum so nothing remains. Apply any of several toppings or another layer of good concrete. Another problem with soupy concrete is that all the rock and sand has settled to the bottom of the pour. It may be bad all the way through.
 
Thanks for all the replies. As usual there are more details. The building is rented. I had nothing to do with specing the concrete. I have machinery on the floor so I have to work around it. I painted a section of the floor in another area in the building with an "epoxy strengthened" water based paint an it kept the dust down for a while. I have a feeling that if I put down enough of the Benjamin Moore floor paint to build a thick film it might hold together a little longer under normal conditions. I have had experience with real expensive epoxy floor installations and they worked ok but the concrete in that case was hard so just about anything would have worked. Two experiences with epoxy floors taught me that they are dangerously slick when even a very small amount of oil or water gets on the floor. I need to keep the dust down to protect a process so I imagine it is paint and then repaint as required to keep things under control. Maybe a tile runner in the heavy traffic areas. Soupy crap concrete is a real trap when you build your own building. The new one will be done right, not hard to get just requires a good understanding with the concrete contractor as most concrete suppliers send it pretty dry and add water as requested at the site. I got screwed once by not being at the site at 4:30 AM when the job started. Costs more as more people are needed to lay and finish the concrete before it sets up.
 








 
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