VCT tile over "rough" concrete


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Old 01-25-11, 07:35 PM
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VCT tile over "rough" concrete

I am refinishing some basement rooms and after scraping up some drywall mud that had fallen onto the floor I got to thinking. The concrete is 50 years old and looks hand finished. It's pretty lumpy, trowel marks that stick up perhaps almost 1/16th in spots (swirls), etc.. What remained of the drywall mud in the grooves seems fairly solid. I'm sure it's not advisable, but I figured I'd ask anyway. Compared to much higher cost floor leveling compound, can it be used to smoothen out some rough spots underneath a new install of VCT tile? I assume not, figuring the tile adhesive won't grip it well enough, or it won't grip the concrete well enough, or being on the floor moisture will be a problem. But like I said, just figured I'd ask...

Also, there are numerous pinholes with a rim of of white calcium(?). It's dry now but in the past this basement has had serious water problems, stemming from improper external drainage. I'm also curious how advisable it would be to apply a sealer or similar product before applying glue and tile? The water problem is non-existent now but was very bad in the past.

Thanks
 
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Old 01-26-11, 04:31 AM
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VCT won't be a good choice if there are any boogers in the floor. It needs 100% flat contact. My main concern would be the moisture problem, with any flooring you plan.
Just as an aside.....since VCT will have to be laid one tile at a time, have you thought about ceramic tile for the area?? You can probably purchase ceramic at a deep discount and since it involves the same motion to install, you could have a nice floor and not have to go through concrete prep for a "perfectly" flat floor.
 
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Old 01-26-11, 05:11 AM
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No gypsum based product will hold up on the floor. You need a product like "Feather Finish" if you plan on smoothing out the floor.





"Flooring Installer for 40 years"
 
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Old 01-26-11, 11:10 AM
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Do not use sheetrock joint compound for any concrete repair . The sheetrock mud has no bonding strength and will release after any tension is applied. Concrete sealers and vapor barriers are ment to stop water vapor migration through the concrete slab. A water membrane is applied to stop water leaving or entering through the concrete. Neither will help if water is coming in from ext. wall . You said that problem is gone so i would not worry about putting a sealer down. As for concrete prep, home depot has a hand tool called a rub brick for 15$ , use that for the high ridges left in the concrete , Hand finshed concrete is very soft and can be grinded manually .Then apply a ARDEX feather finish or a patch with a laytex binder additive . A black thin spread tile adhesive should be used for below grad installation .
 
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Old 01-26-11, 03:28 PM
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Be very careful sealing concrete that will be coated with adhesive/mortar in the future. Many sealers do their job too well and can actually interfere with the bonding of the adhesive/mortar. I would rent a sander to knock down the high spots, then skim it smooth with feather finish or a similar product.
 
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Old 01-26-11, 06:07 PM
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I was going to suggest using a hand grinder to grind down the bumps on the floor, and then using a cement based floor patch (like Mapei Planipatch) to float the rough areas.

I agree with Chandler that VCT tile isn't a good choice for residential applications, but not on his claim that the floor below has to be perfectly flat. VCT tile will conform to the contours of a floor provided those contours are smooth.

The problem with VCT tile in a residential setting is that VCT tile is a flooring that needs to be maintained to stay looking good. Theoretically, VCT flooring is supposed to be coated with acrylic floor finish, and that acrylic floor finish needs to be maintained by either stripping off the dirty floor finish periodically and applying new acrylic floor finish, or by using a floor machine to scrub the dirty surface layer off the floor finish and mopping down new floor finish.

Without maintenance, all that's going to happen is that any acrylic floor finish initially put on the floor is going to get dirty, and then get worn off, and then dirt is going to become embedded in the vinyl composition tiles, and at that point you CAN'T get the tile clean again. The way it's supposed to work is that the dirt is going to get embedded in the surface of the floor finish, and that dirty surface layer of finish gets periodically removed by scrubbing with a floor machine. (Mine cost me $1700.)

Wdingus:
If you've already purchased the VCT tile, what you probably want to do is mop something called "sealer" onto your floor when you're finished installing the tiles. Buckeye makes a very good sealer called "First Down", and I recommend you use that sealer on your floor instead of any finish unless you're willing to buy a floor machine for $500 and up and invest a weekend every 2 or 3 year maintaining the floor.
Sealer is very much harder than floor finish, and so dirt doesn't get embedded in it at nearly the rate that it does in floor finish. With sealer, what you do is apply it over your entire VCT floor when the floor is new (and apply plenty of it). Then, as areas become dirty, you simply clean those areas with a Magic Eraser and then apply more sealer to the floor. What you have to be careful to do is only apply the sealer to the cleaned areas. If you apply sealer over areas that haven't been cleaned with the Magic Eraser, you're simply burying the dirt under sealer, making it very much harder to remove.

But, if properly maintained, VCT tile is a very durable flooring. It's an excellent flooring for apartment blocks where the owner is a "hands-on" manager. That's because VCT tiles are very durable, with a coat of sealer on them are very stain resistant, and if push comes to shove, you can always repair damage by replacing tiles. But, because of the requirement to maintain a coating of finish or sealer between the shoe leather and the tile, they're not the best choice for residential settings unless the homeowner is willing to do that maintenance.
 
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Old 01-26-11, 07:43 PM
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Thanks for all the great info everyone! It's not a huge room so I did buy a "rub brick" and with a little elbow grease it does appear to knock down the high humps pretty well. Also when I asked about sheetrock mud, I should have been more precise. I'm only talking about small areas, smaller than a 1' x 1' tile, where applying it (or something like it) would still leave >50% of the surface of the tile to be in contact with the concrete via glue. No large areas, I realize it doesn't have the strength for that. Just something to keep small dips out of the finished product. In small patches where the concrete has a "grated" appearance. Also it won't be a high traffic area so the sealer route should result in many years of service I think. Thanks again...
 
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Old 01-27-11, 09:57 AM
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No sheetrock mud

Please , I can not stress enough , Sheetrock mud wiil not hold no matter how small .The below grade substrait will expand and contract with the seasons and the joint compound will release. Use a approved patching underlayment
 
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Old 01-27-11, 11:21 PM
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Wdingus:

No don't use drywall mud as floor patch.

Go to Home Depot and buy a product called "Planipatch" made by Mapei, who are the largest manufacturer of flooring installation cements in the world. Planipatch spreads as smooth as any joint compound. It's intended to be mixed with a latex additive (pronounced "adhesive") called "Planipatch Plus" which makes it stick to the floor better and dry harder.

What you should do over concrete is dilute the "Plus" additive with 3 parts water, and use that to mix the Planipatch powder. Spread that on the floor, and then use a bright light laying on the floor to make any blobs or ridges stand out like a mountain range. Use a sharp paint scraper to scrape off those blobs and ridges. Then, apply a second coat of Planipatch mixed with only water. This coat will dry soft so that it'll sand smooth easily. Then, use a paint roller on a pole to paint the Plus additive over that smooth Planipatch. The Plus additive will be absorbed and cause the Planipatch to become harder as the latex additive glues all the cement grains together. That way, you sand a soft product smooth, and then add the additive once it's already smooth to make it both smooth and hard. Keep painting on the additive until the Planipatch no longer turns dark when you paint additive onto it.

Then, install the VCT over that smooth hard Planipatch.

The above will probably screw up your warranty, but I've had excellent results using that method, and I've installed approximately 10,000 square feet of VCT tile in my apartment block since 1995. And, I've discussed the benefits of doing it that way with my local Mapei sales rep, and he agrees that doing it that way should be just as good, but it's not what Mapei recommends. Their recommendation is to mix the Planipatch with the Plus additive only when applying it over anything other than concrete or wood for the first coat. Then, for the second coat, the dilute the Plus additive with 3 parts water and use that solution to mix the Planipatch powder. And, they then suggest smoothing out that second coat and installing the flooring over that.

Someone in here said that the black asphaltic adhesive was required for sub-grade installations of VCT tile. I don't know about that, but I much prefer the clear adhesive. It comes as a light beige emulsion and dries clear. If water coming up through the floor hasn't been a problem, I'd be inclined to use the clear VCT adhesive. It has a much better initial grab, and ultimately holds the tiles down better than the black asphaltic adhesive.

What you should do is pick a starting point where you intend to start tiling. You want to pick a starting point so that you don't have to cut narrow tiles (less than 3 inches wide) along any wall. And there's a bit of a trick to setting your first tile so that it's parallel to your wall. You should have a tile cutter to do this kind of work, but you CAN get buy with a jig saw to do all your cutting.

Also, you should be aware that VCT floor tile adhesive won't stick well to wax paper. The clear adhesive sticks to it more han the black asphaltic adhesive, but once the clear adhesive has dried for an hour or so, neither one will stick to wax paper.

And, you really should roll your VCT tile once it's installed with a 100 pound floor tile roller.
 
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Old 01-28-11, 10:22 AM
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WOW that guy can talk Just use the sheetrock mud!! JUST KIDDING For your cuts, if you do not have a cutter try the score an snap method , and heat score an snap cuts with two or more lines ( door frames , out side corners )
 
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Old 01-28-11, 10:48 PM
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WOW that guy can talk

Mr. Wubbie:

I had the good sense to take Typing as an elective in high school, and that's about the only thing that I learned in high school that was of any real benefit to me during my undergraduate work and post graduate work, and now that I am running my own company. I'm a touch typist (which means I use all 9 fingers to type), and I typically type well over 50 words per minute, which means I can type out my thoughts about as quickly as they come to mind.

So, please don't feel offended if my communications skills on a Qwerty keyboard are superior to your own. Typing out my thoughts comes so naturally to me because I've been doing it for well over 20 years. It's almost as if my fingers do it all by themselves.

Anyhow, I'm so very sorry for you to have to read all that I type, and the only thing I can suggest is that you don't read my posts. Both you and I will probably be better off in the long run if you follow that simple advice.
 
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Old 01-28-11, 11:27 PM
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No offence taken .I am just jealous, and i enjoy your post. P.S my wife nick named me wubbie and i am not a farmer
 
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Old 01-31-11, 06:57 PM
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Thanks everyone, all the great info is much appreciated! The floor is mostly done now. I did get some SLC undrelayment and attempted to level out some rough areas. Mostly successfully... All that's left is the cove base and sealer application. Thanks again...
 
 

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