How To Fix A Bad Concrete Stain Job

reaction to bad concrete stain job

There’s probably nothing worse than a concrete stain job gone wrong (our nightmare scenario). If you find yourself in a situation where you urgently need to know how to fix a bad concrete stain job, no worries, we’ve got you covered. There are a few common reasons why a concrete stain job can go terribly wrong, here’s some:

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In this post we’ll go over how to address each of these bad concrete stain job scenarios.

Fixing Concrete Stain Due To Questionable Product

bad water based concrete stain

You may have just stained your concrete floors and realized there's a big problem...

….it looks bad.

Believe it or not, much of the the time the issues comes from using so called “Concrete Stains” from big box and big ecommerce stores. In this case, you’ll have to completely remove the stain before applying any true acid stain.

Special Note:

From our experience, any product that tells you to "acid wash" or "etch" the concrete before applying their product is junk. They’re “disguised paint” and are designed for only one purpose - to separate you from your cash. We recommend avoiding them at all costs. Concrete Acid Stains are the only true stains for concrete, as wood stains are for wood.

If your concrete is outside or in an acceptable area for it, the easiest way is to rent a small sandblaster and sandblast it off. If you can't use a sandblaster, or if indoors, you can remove it using citrus strippers, heavy duty paint strippers, heavy duty glue removers, a mastic remover, or Xylene (very flammable and aromatic - requiring adequate ventilation and caution - but very effective.)

Make sure to check out our “How to Clean and Prepare Concrete” guide for detailed instructions.

Important: if you’ve already etched your concrete, only our Artist Grade Acid Stain will be effective. All other stains are only standard grade, even our Pro-Etch, and will now be completely and totally ineffective. So be sure to use only the artist grade concrete acid stain, once you've got the mess cleaned up and off your concrete.

How to Repair Accidentally Stained Concrete

spill causing concrete acid stain problems

One problem we hear occasionally is acid stain accidentally getting onto concrete on an unintended area. This is less than ideal and requires a muriatic acid wash and a good stiff brush to clear up.

Important:

It is extremely important that you ensure that you have plenty of ventilation and fresh air. Use mechanical means if necessary, such as fans in windows, one blowing in and one blowing out, etc. Ensure that you wear protective clothing. Particularly you should be wearing gloves, such as disposable nitrile gloves or another chemical and water resistant pair of gloves. Along with the other protective clothing such as long sleeved shirts, long pants, fully enclosed shoes or boots, goggles, dust or face masks, and/or respiratory protection as needed. Be sure to read all cautions, warnings, and instructions on the acid bottles label prior to handling, storing, and/or using.

Mix the acid - 1 part acid to about 5 parts water. You can strengthen it if you need to, but try the 5:1 first. (5 parts water to 1 part acid). Note, you should always start with the 5:1 or even weaker of a mix first, before going any stronger.

The acid will yellow the concrete and eat away the surface if allowed to sit there for any amount of time at all. So it is extremely important to have a water hose running and ready, or to have a bucket of clean water with a mop sitting in it, on the ready.

You dip the brush into the bucket of acid and water, then you shake off the excess into the bucket. Then you sit the brush down on the concrete and scrub it well yet quickly, being careful to not splash or splatter any acid/water mix onto yourself or your surroundings. Then you immediately remove the brush and place into the bucket or a predetermined safe place area, and then either quickly start rinsing the acid mix off the concrete with the water hose already running on full, or start mopping it up with the mop and the bucket of fresh water.

It is very important to get all the acid mix rinsed all the way off of the concrete or all the way mopped up. You can repeat as needed until you get it scrubbed all the way down.

An Area Did Not Take the Acid Stain As Intended

concrete stain too dark and light

There are times when you have areas of your concrete that do not accept the stain as intended. They may be leaving light spots on your concrete that may be indicating a barrier blocking the stain.

We recommend you first take a look at our concrete stain guide and make sure you’ve followed all best practices. It may be that another coat of concrete stain will bring in those areas as the acid in the first coat may have eliminated whatever contaminant was in the way, or opened the pores of the concrete up enough to allow another coat to get in better and take. Then again if it's a petroleum type contaminant you'll need to degrease, re-clean and rinse those areas before they'll take. So be sure and do a small test area before doing it all if possible. If all else fails, you'll need to camouflage those areas during the sealing stage.

If you have areas that are too dark then you can try the acid washing technique mentioned above to lighten those areas.

Fixing Scratches On Your Concrete Stain Job

If you’ve applied some sealant and floor wax to your acid stain and discovered scratches on certain areas, you’ll want to give it a touch up. Here’s what you’ll need to do to get it back to new.

There’s probably nothing worse than a concrete stain job gone wrong (our nightmare scenario). If you find yourself in a situation where you urgently need to know how to fix a bad concrete stain job, no worries, we’ve got you covered. There are a few common reasons why a concrete stain job can go terribly wrong, here’s some:

  • First, do a test to see if applying a fresh coat of wax will fix it. If the scratches are shallow and just in the wax then a fresh coat should do the trick. If the scratches go deeper than the wax, then you’ll need to start with removing the wax in that area
  • Strip back the floor wax using our Floor Wax Remover. Strip it about a foot or so back and away from the area to be worked on
  • Allow to dry
  • If the scratches are only in the sealer then you’ll skip this step, but if they go into the stain and it needs touched up, you can then use a small paint brush and either carefully stain the scratch and then neutralize and rinse, or paint in the color using using a watercolor paint that matches the floor color
  • Allow to dry
  • Re-apply your sealer with a brush and be sure to feather out the last coat to blend it in with the area
  • Allow to completely dry and cure as directed
  • Re-apply the Top Shield floor wax to the area that is stripped. Feather it out as well to blend it in. If you need to, then you can apply a fresh coat to the entire floor to totally smooth it out and blend it in

Overall, making sure your concrete stain job is done right the first time around is the best way to prevent any nightmare scenarios from happening to you. Check out our official guide to concrete staining for the best resource on acid staining.