Branded,

The only thing that counts is what the Adhesive Manufacturer recommends. Consult with their tech team.
Don't skimp on prep, it is less work than trying to fix a small area of hardwood flooring which has popped loose. If you would only paint the floor you would be good to go with what you have done sofar. (sanding concrete with abrasive is like sanding sandpaper with sandpaper if you get my drift)
When glued down flooring starts to move with variations in MC it will easily pull questionable bonded adhesive loose from the concrete.

If the concrete was troweled (read: very slick) many will recommend removing that slick layer, scarifying or shotblasting both do. You have to cut thru that slick layer.

An angle grinder outfitted with a special concrete grinder disk wil do it also (HD rents them out also). "Overkill" (some may call it that) never hurts in this situation, to me "overkill" is good insurance and is typically my standard.

Johannes.

Ok, I'm convinced....I'll see what's available to scarify the surface. I saw a small scarifier at the HD....
Maybe I'll call around to see if I can find a paint store to find one of those sanders mentioned earlier used for garage floors.....

What nags at me though is that almost all the videos I've viewed on Youtube showing concrete prep and gluedown's always show it being done over smooth concrete. Nary a mention of scuffing the surface to improve adhesion.

edit-
I finally found the instructions online for this Bostik Single App....It's apparently the same stuff sold by LL's under a slightly different name. The instructions clearly say that the concrete should not be reflective....so that's that....I have to do more prep on the slab, sigh.....

"Surface Preparation

Step 1

Surfaces must be clean, dry and flat, free of voids, projections, loose materials, oil, grease, sealers and all other surface contaminants. SingleApp may be used for concrete slabs with elevated moisture levels up to 10 lbs. per 1,000 square feet per 24 hours (using an anhydrous calcium chloride test kit according to ASTM F-1869 test method), or up to 85% relative humidity (tested in accordance with ASTM F-2170). Completely remove any adhesive residue or surface contamination by sandblasting, shot blasting or scarifying. When sandblasting, shot blasting or scarifying, the resulting surface texture must be similar to light broom finished concrete. Maximum acceptable floor variation is 3/16” in 10 feet. Areas requiring patching or leveling must be done using a Portland cement-based material (e.g., Bostik UltraFinish™, Fast Patch 102™ or SL-150™ Self-Leveling Underlayment).

PLEASE NOTE: Concrete substrates should NOT be smooth and reflective; they should be a dull or broom- type surface texture for the adhesive/membrane to properly penetrate and bond."

Today I rented a scarifier from HD and did the entire floor + Hallway. I did the entire room in a crosshatch pattern.

BTW, the sister site to this one, under concrete prep, shows a Floor Buffer and sanding paper as adequate prep.

Sister link for concrete preparation.....

http://www.hardwoodinstaller.com/hardwoodinstaller/gluedown-prep.htm

Some people do it differently than people in other areas of the county. If your gluing a quality engineered you don't need to worry to much about movement.

My favorite application is still Bostik MVP4, then Bostik's Best or any of the other over MVP4. The two step may take longer but it's my inner most feeling that having one layer already cured on the slab and adhering to that is the best you can get. Me, I am still wary of the one step adhesives.

Some times you just gotta ask yourself, self, is today my lucky day? Then flip the coin.

Oh, oh...Doesn't the one step have an adequate track record?

Track records for me mean up to three four years. It's not been out that long. And manufacturers certainly don't go out telling the general public they are having issues. But there's so many things that can go wrong. Like not switching out trowels every couple hindered feet.

I like they're use of a regular trowel rather than the other manufacturers that utilize that little teat on the ends that wear down fast. But if your not going to do any real moisture testing then whats the big dif? Gotta document it like I mentioned before, it's a crap shoot with these new adhesives to tell ya the truth. I'd do MVP4 and then Bostiks adhesive before I would do a new one step if it were my floor.

Who said I didn't do any moisture tests? I have a mositure meter, as I said in one of these threads before, I bought years ago from Northern Tools.
I use it to check lumber but it works equally well for concrete. I simply don't rely soley on this device.
I've come used to the visquine/plastic test as it tells me immediately if there's a problems and I can cover a lot more areas with plastic/tape than moving around on my hands and knees with my probe, lol....it only costs me some time (a couple days)
Having said that, if the plastic shows an area that's suspect then I would zero in with the meter.


"Like not switching out trowels every couple hundered feet.

I like they're use of a regular trowel rather than the other manufacturers that utilize that little teat on the ends that wear down fast"

Now this is something I would never have guessed at initially...
Great tip!
Thanks

Oh sure, point out my poor spelling, it was late and I was tired.

No malice intended... I've been know to hit the wrong key now and then too.....But it was a good piece of info. I never would have guessed that scraping and combing the glue over roughened concrete would wear the points down....