Aug 2018 WHAT IS ACID STAINED CONCRETE?
Resulting in a one of a kind custom finish, find out about acid stained concrete and why interior decorators will often turn to acid stained concrete applications to uplift the uninteresting look of concrete slabs. Colloquially referred to as coloured concrete, acid stained colour techniques are a popular application to decorative concrete installations. Making use of various staining practices applied to the already uniform concrete installation, a typical concrete stain mix is made up of water, hydrochloric acid, and acid-soluble metallic salts. When coming into contact with the chemical compounds of the concrete, together with hydrated lime, the stain and the concrete work together by way of a chemical reaction that result in a unique mottled and marbled effect to typical dull grey
Unlike painting because the colour results from a chemical response to the concrete and the stain, acid stained floors create a permanent feature that does not chip, peel or weather with time. The finish results in an uneven, translucent colour that can resemble slate, marble or stone. Where no two looks will appear the same, concrete staining brings a one of a kind, authentic look to any interior or exterior concrete installation.
When applying an acid stain to concrete flooring, walls or even countertops, contractors will follow the below steps in ensuring the end result takes on the desired effect.
The application of acid staining begins with a high pressure wash to clean the surface of the concrete. Ensuring that all grime, dirt and build up is removed, your contractor will also scrub the surface with an abrasive pad or brush to remove any debris that might inhibit or influence inconsistent colouring.
Ensure that the concrete is cleared of any waterproofing agent or muriatic acid. These will inhibit the chemical reaction required during the staining process. To check if the concrete installation has been waterproofed, pour a glass of water onto the surface and check to see if the water beads and runs away. If there is no application present the water will be absorbed by the porous concrete indicating that an effective acid staining process can proceed.
Next, the concrete floors will be sprayed with the water, hydrochloric acid, and acid-soluble metallic salts stain mix, initiating the chemical reaction. Keep in mind that how the concrete surface has been trowelled or if any patch work or repairs have been applied will influence the outcome of the stain. For the best staining results it’s advisable to apply a stain to a newly applied concrete floor or concrete flooring that has been buffed out with a micro finish overlay.
Reacting to the hydrated lime and the chemical compounds that come into contact with each other, both the concrete and the stain will see the start of the concrete colour begin to change. During the initial process the concrete stain colour will undergo what is referred to as the “Ugly Stage”. During this time almost every home owner witnessing the staining process will panic that they have selected the wrong colour however, as the acid is neutralized with an alkaline agent such as ammonia and water the lasting effect begins to reveal and the end result is more closely aligned to the desired colour finish.
The second last step to completing a concrete acid stain, the concrete floors will need to be cleaned removing excess water and neutralizing agent. Once mopped up, use a vacuum to remove any additional residue before it can dry to the concrete.
After allowing the floor to adequately dry, this will offer a good indication of how the final finish will appear. Next apply a sealant to the stained installation adding a layer of protection to your concrete flooring in the final step of the staining process.
While seemingly a simple process to follow, if inexperienced, it’s best to recruit the help of a contractor or professional concrete staining company to assist you with this home improvement job. Messy and known to be hazardous if not applied with extreme care, acid stain professionals are best advised to guide you with the desired finish, colour and application ensuring a professional and appealing end result.