You’ve decided that you want a beautiful new concrete floor or slab and now you’re choosing which stain, epoxy, finish, or paint you want. But did you know that there’s one more decision you need to make first?
In order to make your treatment work properly, you’ll need to roughen the surface of your concrete. You can do this in two ways: acid etching concrete, or grinding concrete. In this post, we’ll talk about why you need to etch or grind concrete before applying stain, how each of the two methods above work, and finally which you should choose.
Why Do I Need to Grind or Etch Concrete to Apply Stain or Finish?
For any type of treatment to stick, your concrete floor needs to be porous. That is, it needs to be able to soak in the stain, epoxy, finish, or paint you give it. Anything applied to a flatter surface will either slide off, turn blotchy, or become damaged very easily.
To make your concrete porous, the surface needs to be roughened. The degree of roughness is subject to debate, but in general, it should feel between 60-120 grit sandpaper. Anything coarser will leave unattractive swirl marks or grooves in your final product, and anything finer will not last as long or work altogether.
How Does Concrete Grinding Work?
Grinding is the most conventional and effective way to prepare your concrete for finishes and stains. A concrete grinding contractor will have all the tools necessary, including a grinder with diamond grinding pads, floor buffer, dust shroud, and power washer. The process is very straightforward: after cleaning and degreasing the surface of the concrete, the grinder traverses the entire space and all residue is cleaned before applying the finish, epoxy, or stain.
Grinding produces the best results and is safer than other methods overall. However, it can be difficult to acquire all of the tools necessary to complete the job. Hiring a concrete contractor such as GWC Decorative Concrete is the simplest way to get your project done.
How Does Acid Etching Concrete Work?
One of the less labor-intensive methods of roughening concrete is through the application of acidic material to your floor. Muriatic acid is the most common etching acid for this purpose. After diluting, the acid is spread across the entire floor with a sprayer and allowed to sit for 2-15 minutes. During this time, the acid reacts to create many small holes. After neutralizing and washing away the acid, an epoxy or sealant can be successfully applied before a final stain or paint.
This method is ideal for small spaces that are manageable to spread the acidic solution around on or for DIYers who do not have access to grinding equipment. However, there are several drawbacks to this method. First, results are usually not as effective in comparison to grinding, which will limit how long your work will last. Acid is also a dangerous substance to work with, which can cause injury and environmental concerns.
So, Which Method Should I Choose?
We’ve highlighted the pros and cons to each method –but which is the best? Like with most things, it depends. If you’re intent on tackling the project yourself, concrete acid etching will be much quicker and easier to manage. For all other purposes, concrete grinding will produce the best results.