Frequently Asked Questions About Acid Stained Concrete

Q: What is acid stain or chemical reactive stain?

A: Most acid stains are a mixture of water, hydrochloric acid, and acid-soluble metallic salts. They work by penetrating the surface and reacting chemically with the hydrated lime (calcium hydroxide) in the concrete. The acid in the stain lightly etches the surface, allowing the metallic salts to penetrate more easily. Once the stain reacts, it becomes a permanent part of the concrete and won’t fade, chip off, or peel away. Like stains for wood, acid-based stains are translucent and the color they produce will vary depending on the color and condition of the substrate they are applied to. Each concrete slab will accept the stain in varying degrees of intensity, creating natural color variations that bring character and distinction to each project. What acid stains don’t offer is a broad color selection. You willl mostly find them in a limited array of subtle earth tones, such as tans, browns, terra cottas, and soft blue-greens.


Q: What are some of the benefits of acid stained concrete floors?
• Fit a variety of decors -- from Old World and Tuscan to Beach Cottage and urban loft.
• Have a rich, leathery appearance (resembling fitted stone).
• Are easy to maintain (Use a damp mop as needed and mop-on wax once a year).
• Are gentle on your budget (especially for new construction).
• Offer relief to allergy sufferers .
• Are highly energy efficient . For details read "What Makes Concrete a Green Building Material?"
• Last as long as your concrete.
• Are environmentally friendly (a preferred green building material).


Q: How do I know if stained concrete is right for me?
A: If you love their look, stained concrete floors are the perfect choice. However, if you object to "imperfections" such as hairline cracks, uneven tones and "blemishes" (also found in many natural materials), then you may prefer a more traditional floor covering. Our clients believe these flaws add "character." Some designers deliberately chip, hammer, pour rock salt or press leaves on newly poured concrete to add interest or to achieve a "distressed" Old World look.


Q: What services do you provide with respect to acid staining?

A: Derek Nielsen, LLC. travels throughout the greater Southeast of the US providing the materials and labor to prepare, score, acid stain, seal and wax the floors. For older floors, we may recommend a subcontractor to prepare the floor by either grinding/sanding the floor or resurfacing it with an overlay.


Q: When do we let our builder know that we are going to use stained concrete as our flooring choice?

A: Preferably before the foundation is poured. Our "contractor information guide "can help you, your builder and subcontractors avoid common mistakes.


Q: When does staining take place in the schedule of new construction?

A: If you are "scoring your floors" (saw cutting a pattern in them), we arrive after the foundation is poured and before framing begins. That way the scoring pattern can go "under" the walls.
We return to STAIN AND SEAL the floors as soon as the structure is "dried-in" and before the dry wall is hung. ("Dried in" for us means the roof is on and doesn't leak; the windows are in.)
We return right before move-in -- after your building project has been professionally cleaned -- for a final wax.

Q: How do you "score" the floors?

A: Floors are saw cut with a diamond blade using a variety of concrete cutting equipment. We typically score a 24" x 24 " or larger square grid on a diagonal, but we are more than happy to suggest other designs or follow your architect's drawings.

Q: What about borders?

A: Borders are optional (if we score before framing) and required if scoring begins after the framing is completed. (Unless, of course, no scoring is desired.) Borders can be stained a second color, if desired. (Adding a second-color border to a dining room or entry can add drama and definition.)


Q: How do we protect the floors during construction?
A: Our instruction sheets provide details on how to protect the floors both BEFORE and AFTER we arrive. After the floors are stained, they should be covered for the remainder of construction to protect them from spills, glue, marks, paint, etc. We cover the floors with 15# roofing felt, overlapped and taped only to itself. It is the owner's and the owner's builder who are responsible for the care of the floor during the duration of the construction process.


Q: What are some of the most commonly made mistakes?
A: These vary from nailing support walls into the concrete to taping directly to the concrete. We provide builders and framers with detailed instructions to prevent most common mistakes.

Q: How much does it cost?

A: Cost per square foot depends on total square footage, scoring pattern, and location. Our fees decrease as the square footage increases.(ie, price breaks at 1000, 2000, 3000 and 4000 sf). We provide a written proposal, based on your specifications, within a day or two of your call.


Q: Which rooms should I stain?
More and more residential clients are staining every room of the downstairs, including the closets, baths, bedrooms and porches. In addition to price savings, you will add to the flow of the house and, when porches are included, extend the indoors out ... blurring the line between indoor and outdoor living spaces.


Q: What do you need to know in order to give us a quote on our job?
A: Please call us BEFORE the slab is poured. Provide the total square footage to be stained, the scoring pattern or other special touches (star, compass rose, border, etc.), if any, and your location.( If your project involves older concrete, we will also need to know how your floors are currently covered.) We are also happy to review your plans and make suggestions.

Q: Do you work on older floors?

A: It is much more cost effective to stain new concrete that has not been sealed or covered with another floor type. However, depending on the condition of the concrete, the size of your job, and your location, we may be able to prepare the concrete for staining by grinding it or capping it with an overlay. The latter option pretty much doubles the price of staining. Floors previously covered by carpeting can sometimes be ground lightly to remove or minimize stains and reopen the pores of the concrete. Floors covered with tile, wood or vinyl usually require an overlay. Since we are a fairly small operation, we ask clients to remove the old floors before we arrive.


Q: What are the color choices?
A. Even with our color chart (found on this site), tones will vary according to concrete composition and conditions during which the concrete was poured. The sheen also varies depending on the concrete's porosity, the trowel finish, and the sealer/wax finish you select. We offer matt, satin, semi-gloss or high-gloss finished (and recommend satin and semi-gloss for most applications.)

Q: Where can I learn how to do this myself?
A: We recommend that you always use a pro. After all, your home is one of your most important investments and staining and sealing a floor property requires a lot of know how. (We've been doing this since 2001 and have stained hundreds of homes and businesses.) But if you insist, Acidstain.com is a great DIY friendly online forum that can help you find the way. You might consider contracting the scoring portion of your project, as the equipment used to decoratively score concrete can be difficult to rent and expensive to purchase for one time use.


Q: What is the best way to clean my finished stained concrete floors?

A: Clean interior stained concrete by sweeping first and then mopping with water. Occasional waxing (about once a year in most residential applications; quarterly in commercial applications) will also keep your floor protected and looking new. Do NOT use harsh detergents, vinegar or chemicals. Before waxing, mop floors with a "neutral floor cleaner."
Use a water hose and squeegee on outdoor patios. Do NOT use a pressure washer. Reapply sealer as needed. (For safety reasons, we do not recommend wax for outdoor surfaces.)
For accidents, disinfect with a capful of 2 percent bleach and a capful of ivory in a bucket of water. We offer our clients a Care Sheet with recommended products and other tips.