Dull Spots from Rain Water on Marble Patio Table
by Gail
QUESTION:We purchased a stunning white (Taj Mahal) marble table---seats 8---for use on our patio. It rained recently. The rain left the table dull and "water stained" with water spots. I have tried a damp sponge and soft cloth to remove marks. No luck. The table is inlaid with semi-precious stones such as lapis and cornellian.We adore the table. It was expensive. I'm frantic that we now have a dull spotted table when before it was shiny and clear. 1) Is there any hope? 2) What should we do? 3) Is there any chance that in taking your recommended action we could do further damage. We would like to solve the problem, and then find a way to maintain the table. I hesitate greatly to put a sealant on it. ANSWER:First... there is hope! In fact, you should be able to completely restore the shiny marble table surface quickly, easily and inexpensively, but this isn't a matter of "cleaning marble".... it's repair.Marble is sensitive to acidic substances like fruit juice, coffee, wine. When in contact with an acidic substance a corrosive chemical reaction occurs which eats into the marble. The surface layer of your table was originally polished using intense friction and abrasives to a high shine. The polished layer in spots was worn away by the reaction revealing the more dull and lighter-colored marble (polishing marble makes the colors more saturated) underneath. This reaction is called "etching" and you can learn more about it on many pages of our site. A good place to start is our Marble Polishing page (click here). Using harsh cleaning products (nearly all common and name-brand cleaners are too harsh for cleaning marble) can result in etch marks as well, which is why you should use only products safe for cleaning marble like those we recommend at the Stone Care Center. Rain water and water in general is typically not an issue, however, with all the air pollution in southern California you sometimes get an "acid rain", which will etch the marble leaving the dull spots. This can sometimes happen with acidic well water and even some city water supplies can be a bit acidic. The longer a damaging substance remains on the marble the more corrosion occurs, so some spots may be worse than others. Luckily, etching can be repaired rather easily in most cases using the Etch Remover / Marble Polishing Paste, which is designed specifically for this issue of marble repair. You simply mix the paste, apply to the etch marks and rub with a soft cloth. You are in effect re-polishing the etch marks and restoring the "finish" so it matches the rest of the shiny "polished" surface. As noted etching is a matter of degree (longer exposure = more severe damage) and the remedy depends on the severity. Most etching is mild to moderate and the above product is very effective. However, if etching is severe (spots are rough to the touch), then a marble cleaning and maintenance professional may be needed to re-polish the marble table. Why? Simply because the more raw or rough or uneven marble or any stone is the more vigorous and skilled treatment is required. The great thing about natural stone is that it can almost always be restored to like-new condition, however, it sometimes takes the considerable knowledge, skill and experience of a good pro to do it well. The Etch Remover product is designed to be used by an unskilled homeowner on small etch marks that are still relatively smooth representing the very last step of polishing marble. Again, it is rare to have severe etching, so you should be able to handle this on your own. However, if there are etch marks over the entire surface (as I assume there could be) then you may consider hiring a pro. Small, isolated etch marks are easily restored using the product, but repairing multiple spots over a large area requires some skill, so there is a chance for an uneven finish. Having said that, you won't do any more damage to the stone if you want to give it a shot yourself first. We typically recommend using the Etch Remover first even in severe cases because it does an excellent job, won't cause any further or other damage and is far cheaper than a marble cleaning and maintenance professional. If the etching turns out to be too severe, then you can still hire a cleaning marble / marble maintenance pro. As you will learn by researching on our site, applying a stone sealer does not prevent etching. Sealers prevent staining (substance absorbing). Etching is a completely different and unrelated issue to staining. Only avoiding contact with acidic substances will prevent etching. Thus, you should always use coasters, place mats and trivets and given this experience you should cover your marble table when not in use to keep the rain off. So, I suggest using the Etch Remover / Marble Polishing Paste. One bottle is likely enough, but given the size of the table you may need two bottles. And it's a must-have marble cleaning and care product for polished marble, travertine and limestone (not for use on honed surfaces though), so having some left over would be good anyway. Good Luck, Ryan P.S. Get all the facts, answers, explanations and simple solutions with step-by-step instructions for any issue, problem or question with our Granite & Marble Maintenance Manuals. |
