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Flooring and Carpeting/Tiling over painted concrete basement floor


John wrote at 2013-02-01 02:03:01

I recently made a newbie mistake of using Killz to "paint" the bathroom floor after discovering mildew and molds under the vinyl that I ripped off a couple of nights ago.

Home Depot guys told me that I need to strip off the "paint" but does Killz qualify as paint? It has more of a primer (flat) feel to the surface than semi-gloss or gloss feel.

I used Mapei product for my first tiling project, which I did not "paint" the concrete slab. I felt that I needed to paint/clean the mildew on the bathroom floor prior to tiling otherwise I would not have done anything to it. Do you recommend that I follow what you have advised to Les or can I use regular thinset from Mapei?

Thanks for your help.  

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Ron Unger


Floor and wall preparation and layout for the installation of ceramic, porcelain and natural stone tiles. Tile repairs, waterproofing of shower seats, pans, walls, steamers and floors. Floating and setting shower pans, walls and floors. grouting, cleaning and sealing sanded, unsanded and epoxy grouts. General knowledge of tile products and the application of products.


I've been in the ceramic tile trade for 21 years, the first 10 years as a tile finisher and the last 11 years as a journeyman tile layer. I've worked in the residential and commercial fields. I've served as Forman as well as layed tile on jobs such as; Car Dealerships, Grocery Stores, Movie Theaters, Hotels, Office Bldgs. ect... As well as; Multi Million Dollar Homes and Condominiums.

I've attended a tile finishers course and a tile layers course. I am also trained in blueprint reading as well as OSHA certified.

Awards and Honors
The company I work for won an award for their ceramic tile work done on the Mexican Consulate in Chicago from the "Tile Contractors Association of America", which I was the forman on.

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