Q&A / 

Cultured Marble

DEAR TIM: I am really fed up with the constant care that my ceramic tile bathtub and shower surround requires. I would love to have a single piece of marble on each wall. Since I have not yet won the lottery, do you think the cultured marble products will suffice? Will these synthetic products loose their shine over time? Is it possible for the average person to install cultured marble products? Can you repair pieces that are damaged? Mack T., Liberty, IN

DEAR MACK: Let's set the record straight before we go any further. Cultured marble is really not a totally synthetic product. Real natural marble dust is used to make cultured marble. This ground up marble dust accounts for over 75 percent of the volume of a typical cultured marble product. When mixed with a liquid polyester resin, the marble dust forms an attractive and durable bathroom and kitchen product.

Real marble can be a nightmare in a bathroom or kitchen environment. It is naturally porous and as such can stain easily. Hair coloring products, chemically reactive shampoos and conditioners, and many colored liquids can cause staining problems with natural marble. Because the resin coats all of the marble dust particles making them impervious, high quality cultured marble can withstand stains that might otherwise harm natural marble.

The cultured marble industry is quite young and very interesting. It got its start in the late 1960's as a "garage" business. Small volume local fabricators sold their products to plumbing and building supply houses. The industry continues to be quite fragmented and there are hundreds, if not thousands, of small companies who produce cultured marble all over the United States. Unfortunately, the quality of the finished product can vary widely from one manufacturer to another.

Several years ago, many of the leaders in the industry founded the International Cast Polymer Association. This group has created a certification process that allows consumers to purchase high quality cultured marble, granite, onyx and solid surface products with confidence. If you buy your cultured marble from a certified manufacturer, you should get a product that will maintain its brilliance for many, many years.

Cultured marble can be used to create many bathroom and kitchen products. Sinks with integral tops, bathtubs, whirlpool baths, shower basins, back splashes, wall panels, etc. are all possible. Since it is a molded product, manufacturers can create an infinite amount of designs tinted to any color. The clear finish can be ordered high gloss or satin from many manufacturers.

It is possible to repair scratches, chips, and minor blemishes. A certified repair person can re-buff the surface with a special mixed gel-coat compound. Cracks and broken pieces are virtually impossible to repair. It is not possible to apply a complete new clear finish to a cultured marble product once it has left the factory.

Installation of cultured marble tub and shower surrounds is really simple. The process goes quickly if the wall surfaces are plumb, square, and flat. The walls behind the cultured marble should be flat white. Colored drywall or gray cement board can show through some light colored marble products. Dry fit each piece to make sure they are sized correctly. Remove dust from the back of each piece with rubbing alcohol before you apply clear 100 percent clear silicone caulk adhesive.

I prefer to start my installations with the piece that goes on the wall I face as I enter the tub or shower. If you install the side wall pieces first, your cuts on the final piece have to be perfect. That can be tough for a beginner. Caulk all seams with a colored 100 percent silicone caulk that will closely match the cultured marble.

Cultured marble is easy to care for once installed. Avoid any cleaning product that contains abrasives. Use a squeegee after each shower to quickly remove water drops from walls. If hard water deposits accumulate on shower or bath walls, they can be dissolved easily with vinegar applied from a spray bottle. Apply the vinegar and wait for 45 minutes to an hour. Rinse the softened deposits with clear water and a sponge or cleaning rag. Heavy hard water deposits may require multiple vinegar spray applications. Cultured marble that has lost its shine can be restored by using Gel-Gloss or Counter Top Magic once a year. Your local fabricator can sell these products to you.

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6 Responses to Cultured Marble

  1. I have a cultured marble shower enclosure. It is 19 years old and still looks great. However, every place that I have accessories held in place by small suction cups have left a round stain. Same problem in our tub where the tub mat was. How can these stains be removed?

  2. Could someone please help??? I had purchased my new home in January... 4 months ago and my shower is making me sick.. headaches, nosebleeds, etc. My husband and I noticed a small bead of black along the caulk on shower floor. He thought it was mold but knew otherwise when we looked closer. It was several holes in the caulk getting larger! My husband recaulked it, but the hole just kept getting bigger. He finally did it again and left the shower dry for several days before we got it wet. Weeks went by and I started becoming sick... I have severe allergies and sinus issues. I can smell mildew and it's getting stronger. He pulled out the piece that he caulked and what do u know? Mold n mildew behind the piece and along the backing. We thought it was one piece, but over the days my nose told me something different. He pulled out another piece and MOLD was on it and the glue!! Who do we call to fix this??? Do we order new cultured marble pieces??? HELP!!

    • Type: biofilm into my search engine NOW. You need to sanitize and CLEAN the gunk off the sidewalls of the pipe that extends from the shower drain you stand on down to the p-trap.

  3. Dear Tim, I currently have a fiberglass shower stall that has been leaking though the glass door seams. Ultimately producing some black mold. Besides getting rid of the mold, I am remodeling my shower and can't decide on cultured marble or porcelain tile. my daughter who works for a tile place swears by the tile. She says the marble is too heavy, very porous and requires resealing annually by a professional. My installer who use to work for a marble place swears by the cultured marble. He claims that the tile tends to leak more and it could be tough to keep the grout clean. Other than the usual biweekly/monthly shower cleaning (depends on how quickly the mold and mildew develop) , I am not one who likes high maintenance bathrooms. If I have to tear out my shower, I want to upgrade which is why replacing the fiberglass shower with another fiberglass shower is not an option.

    The pattern of choice (tile or marble) will be mainly white with some grey swirls running though it so if II go tile, I will need to use a light colored grout which I am told will require a lot of maintenance keeping it clean can be prone to leaking. If I go cultured marble I am reading horror stories about staining problems and having to reseal every year or two. I really like the idea of not using grout but my may concern here is the maintenance with either product.

    Can you provide any advise on which material is better to use and why from a maintenance standpoint? what are the pros and cons to using cultured marble vs porcelain tile? I never thought about the marble chipping so some of your points above added to my concerns about using marble.

    Thank you, Diane

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