The Care and Feeding of Soft Rock
October 25, 2018
Posted by D. A. Burns
Today we’re going to touch on and answer customer questions about caring for three big players in the interior surface game—marble, travertine, and limestone. If you saw “soft rock” in the title and thought we were going to talk about James Taylor, sorry. Next time.
The point is, although your stone flooring, shower enclosures and countertops are hard as rock, they aren’t immune to harm.
Over time, a softer stone can be more sensitive to food, cleaning products and wear than a harder stone. Minerals are often ranked in hardness using the Mohs hardness scale, which ranks diamond at 10 and talc at 1. Using that scale, a hard stone is an 8, kitchen knife is a 7, a soft stone is a 4 and your fingernails are around 2.5.
Why wouldn’t everyone just use the Led Zeppelins of stone – granite or quartz? The cost and hardness of those stones isn’t always required, and each type of stone has a look that isn’t duplicated by any other. In typical use, every type of stone will last longer than we will. We just need to keep the stone looking as good as possible to avoid unscheduled replacement.
The difference in both hardness, and how easily water travels through a stone, creates different levels of care for each stone type. Please refer to our very basic (but informative) chart of the most popular stone surfaces:
The main concerns with softer stone are tiny scratches that remove shine, etching (dull spots) from exposure to acidic substances, and staining from liquids that penetrate into the stone surface. Let’s break these down even more.
The easiest way to keep hard floors looking good is to avoid tracking in grit, so a good wipe-off mat at the door, area rugs in traffic areas and/or removing your outdoor shoes is recommended. Since sand is mostly quartz, the harder material will damage the softer with any kind of abrasive contact. Avoid sliding any hard items across countertops and use a cutting board. Sealers won’t make the stone harder but will help keep soil from getting bonded to stone and grout. We’ve included a visual below for those who need to see it to believe it.
There’s a long list of things in the home that can etch soft stone (marble, travertine, limestone). Fruit juices, wine, face creams, toothpaste, even some products sold to maintain showers will eat into the surface. Best practice is to keep these from getting on the stone surface and remove quickly if they’re spilled. Mild etching can be polished out; severe etching requires a more in-depth (costly) refinishing. A sealer won’t make stone acid-proof, but may give you a little more time to wipe up spills. Etching can look a little something like this:
Unless it has a rough texture, even unsealed stone will give you some time to wipe up a spill before it soaks in deep. The most problematic stains are ones that no one notices for days or weeks. The slow leak from an espresso machine, a slow buildup of rust in sinks and showers…these are often not noticed until they become unpleasantly obvious. This is where a sealer really shines, keeping what might become a stain on the surface to be easily cleaned away, reducing the need for a restorative grinding and polishing.
A Few Common Questions
Q: I kind of like the non-reflective look. Does my marble have to be mirror polished?
A: Nope. Some people believe that soft stone should look as soft as a thousand-year-old statue, and we’re seeing low-sheen as a trend. We’re even seeing granite and porcelain being honed, ‘flame finished’ or ‘leathered’ to give it a matte look like weathered outdoor stone. There’s no right or wrong to the amount of reflectivity you like, just be aware that it will take more care to maintain the “shiny” on a softer stone.
Q: How do I clean my stone surface?
A: Use a neutral pH detergent and rinse with clear water. Avoid anything with abrasives or acids. Scouring powder like Ajax, Comet and Bon-Ami can be used on a glass cooktop or granite counter, but the abrasives they contain may be harder than other types of stone. Many of the products sold as shower and tile cleaners use acids to break down soap deposits quickly. They won’t hurt a ceramic tile or plastic tub surround, but will etch stone. Finding a non-acidic cleaner might require checking the Safety Date Sheet (SDS) of the product, which can be found on-line. Avoid anything with a pH rating below 7.
Note: We’re hesitant to recommend a product, as product formulations can change.
Q: Is sealer really worthwhile?
A: Stone merchants recommend sealer for all stone except non-absorbent slate and quartz. A sealer may be needed for any installation that uses cement grout. Because people often use cleaning products that can damage their grout, stone and sealer, most suppliers of soft stones recommend a thorough cleaning and sealing process every year.
Maintaining a properly sealed soft stone isn’t too much different from other stone, tile or hardwood surface. Knowing a bit more about your stone investment may help keep it looking great for the next 300 million years.
A word from our sponsor
Although we’d love to clean your stone every year, we have some sealers that can help extend the time between restorative cleaning, and really extend the time between sealing. They cost a little more, but use very small molecule carriers to get the sealer deep enough into the stone, enabling 15 – 25-year warranties.
Call us for a free quote on our stone and tile cleaning and sealing services, indoor or out. Minor scratch and etching removal, too!
More about the Mohs scale
If you’re a Boeing engineer, here are your links to more technical information:
Mohs scale of hardness is a simple approximation of scratch resistance. About the Mohs and more: Mohs’ explanation
More than you ever really need to know about stone: The Natural Stone Institute