Acid-stained concrete creates a rustic look for an outdoor patio. (Rita LeBleu / American Press)
Last Modified: Monday, April 21, 2014 5:06 PMWhen the deCordova home was built in the ‘30s, the concrete slab construction may have been unusual, but now it’s the norm.
Slab foundations can keep water pipes from freezing and keep bugs and rodents from getting under the house, and slab foundations can cost less than some pier foundations.
But it wasn’t until recently that homeowners began to see the slab as not just foundation but also as flooring. According to Ron Guidroz of Creative Concrete by Ron, the decision for finished concrete flooring needs to be made early in the planning process and communicated to the builder.
The best results come from working with a slick finish, one that can be finished to look almost like marble. “The actual term is hard trial finish, the slicker the finish, the prettier the stain,” he said.
The grade and quality of the concrete is a factor as well and the general contractor or builder will need to know that the concrete will be acid stained. “Ash is a common filler and you can’t stain it; the stain won’t bind to it, Guidroz said. “When you do, the floors wind up with white splotchy marks down the road. The percentage of ash is a variable and ideally should be less than ten percent.”
Finishers won’t be able to use any spray-on hardeners, additives or sealers either as these products also affect the concrete’s reaction to the acid staining process.
Contractors will need to use only blue chalk, not black or red for marking walls and doorways because any color chalk but blue leaves a mark on the concrete that will affect the final finish. Guidroz also recommended cleaning the floor of all debris and covering the cement with building paper after the walls are blacked in. Rusty nails, oil from tools and even tape, if you tape your covering to the floor rather than to another piece of the paper, can stain or change the chemical makeup of the concrete, marring the final appearance, according to Guidroz.
“Once the home is finished, that’s where I come in,” he said. “It usually takes me about a week to do a 3,000-square-foot house. That includes doing the scoring as well as the staining. Guidroz said that being the last person in on the job site also means that the home is heated and cooled which can affect the floor finishing outcome.
Stamped overlay is becoming more prevalent in homes in Southwest Louisiana. It’s the process of using a cement product that’s about the thickness of a tile. This product can be stained to look like wood, brick, slate or stone, Guidroz said.
But what if my concrete cracks?
Beau Betbese of Dunham Price has 30 years of experience in the industry and said that all concrete cracks and though you can’t guard against that happening, you can try to control where it will crack. “It doesn’t necessarily mean that your
house is structurally unsound,” he said. According to Betbese, concrete cracks where there is a weak spot such as a 45- or 90-degree angle. “We’re not talking about cracks caused by settling or weight, but by shrinkage. All concrete shrinks as it dries. It doesn’t become a major problem unless the crack grows larger making the foundation uneven or unlevel. A good foundation begins with good groundwork underneath, according to Betbese.
Adding water to the concrete after it gets to the job site is necessary because the further the job site is from the mixing plant, the less pliable the mixture becomes, but adding too much water just to make the concrete easier to work can compromise the quality of the product, Betbese explained.
There have been advancements in the concrete industry since the ‘30s such as the addition of chemicals used to retard or accelerate the setting of the concrete. Synthetic and metal fibers can be used today instead of traditional wire mesh.
If your stained concrete floors crack, Guidroz said, “We can come out and restain the crack, making it less noticeable. One of the first things they teach you in this business is crack repair because cracks are so common.”
Ron worked as an insurance salesman and financial planner until 2004 when he began this concrete flooring finish business. According to Guidroz, some stained concrete floors can cost less than installed tile. Stamped concrete floors are more labor intensive and the cost varies.