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concrete floor with carpet adhesive

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9.1K views 15 replies 10 participants last post by  GO Remodeling  
#1 ·
I am going to be tiling our new office and there is carpet adhesive on the concrete floor. One section comes off fairly easy the rest of the floor is not coming off at all. Is it possible to go over the adhesive or is that not an option?
 
#3 ·
Ardex makes some wonderful tile installation materials. Here is a how to, or more importantly, how not to guide from them:

The best way to remove most contaminants is by scarifying, shotblasting or similar mechanical method. Removal must be deep enough to eliminate all penetrated contaminants.

Methods to Avoid

Acid washing (or acid etching) is not recommended because it is difficult to control, to fully remove the residue, and to properly neutralize. Further, the acid can penetrate into the porous concrete and chemically react with the cement, thus affecting the long-term integrity of the concrete. Acid washing will not satisfactorily remove grease and oil.

The use of sanding equipment is not an effective method to remove curing and sealing compounds.

All types of solvents should be avoided. Their use will drive oil, grease and other contaminants further into the concrete, only to permit their release back to the surface at a later time. Physically removing oil-contaminated concrete is the only sure way to ensure a clean substrate.

Sweeping compounds can leave an oily or waxy film on the surface of the concrete. Their use can create a bond-breaking layer that will result in a flooring system failure. Using a clean dry broom, sweep and vacuum the surface prior to placing any underlayment or topping.

Also, never use adhesive removers or solvents to remove contaminants from porous concrete. These materials can carry contaminants into the pores of the concrete, which will later migrate back to the surface resulting in a floor covering bond failure.
 
#12 · (Edited)
4" razor scraper for small areas

Scrape-Away plate on a floor sander/buffer for large areas

Either way you sand the HELL out of everything with the heaviest grit sandpaper you can find AFTER there's very little left but residue and dust.

ALWAYS spill some hot water on a test patch and give it 20 minutes to soak. Cheaper adhesives will totally melt and then scrape off with almost no effort. The better and best adhesives are much more resistant. Where this system works you want to TIME the dissolving, scraping and thorough mopping/rinsing so you're right on top of it scraping when it's soft and easy. Leave the puddle too long and it gets stupid messy. 2-3 floor fans should dry it up. Never hurts to run a heavy grit sander over the slab once it's good and dry.

Good luck.