Painting basement concrete floor

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Posted by: from Caledonia
12/15/2012 at 11:49:41 AM

In the instructions for painting my basement floor, it states that the concrete needs to be etched. What is etching and what type of tool do I use to do it?

I plan on using a latex paint. Is the phosphoric acid used to neutralize the concrete?

I had 4 places where the concrete was dug up and then re-concreted. How long do I have to let the new concrete cure, before I start working on painting?

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Date/Time12/15/2012 at 12:08:37 PM

I would use a concrete sealer before you use any paint.

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Steve from Simcoe Services in Coldwater
Date/Time12/15/2012 at 12:41:55 PM

Etched also ruff sanding. This is must do if their is exisiting paint on floor option primers. None painted conrete sometimes is verry smooth. Remove dust, vacuum up. Broom will not get dust out.

PS. I'm not a painter.

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Date/Time12/15/2012 at 4:41:34 PM

Hello Neil,

Etching means sanding / scratching the entire surface to remove any residues like old paint, grease dirt etc. and to make it "rough enough" that the new paint will "stick" to the surface.

"...Is the phosphoric acid used to neutralize the concrete? ..." Don't use any thinners or acid to remove old paint etc. because the concrete sucks in / wickes up some ingredients of your thinner or acid and this stuff may prevent the new paint to adhere properly to the concrete. (chemical reactions)

"...How long do I have to let the new concrete cure, before I start working on painting? ..." actually 28 days unless you have used fast curing concrete. You have to wait at least until the concrete is dry enough but don't use heat blower and let them blow directly on the concrete patches to speed up the drying process because it would only dry the surface and interrupting the capillary action. The result would be that the concrete would need way more time to dry.


3D-Tile-Design - Bertram Tasch

Maple Ridge, BC (Greater Vancouver)

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Date/Time12/15/2012 at 8:19:27 PM

Etching is actually roughing up the concrete by a chemical reaction. Any paint supply store will have etching chemicals, either liguid or powder. The instructions are on the container, but you basically wet the concrete spread the chemical out and use a stiff brush to rub it in, it neutralizes the concrete and roughs up the surface.

If you have any paint on the floor right now, it would be best to completely remove it. At least remove all the loose stuff. Tool rental stores have sanders for concrete, and if you use water the dust is minimal. You can also smooth out the transition from the old to the new concrete. Any grease/oil spots, use TSP or muriatic acid to clean them first before etching. Concrete takes 28 days to fully cure, but if you can wait longer, that would be best.

Concrete is one of the hardest surfaces to get paint to stick to. Most plain latex paints will not work, you need to use at least a 2 part expoy paint that is designed for concrete. I have had very good sucess with the products from PPG, BASF and Ucoat-it. Bear, rustoleum and most homeowner DIY type products are not very good.

Remember prep is everything with any paint project, but especially concrete.

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Date/Time12/16/2012 at 12:34:55 PM

Hi Neil;

Etching is performed to open up the surface of the concrete so that the product that you are applying adheres properly and won't peel. We use a grinder to acheive proper surface preperation. The concrete should cure up to 3 months before any product is applied over top of it.

You may want to research other products if you intend to have heavy traffic on your concrete floor.

Have a great weekend.

Joe Mckenzie,

Evermount Garage Solutions.

416 824 3629

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