(Click on the Question for the Answer)
Do I need to seal my granite countertop?
Type of granite:
Some granite is more porous than other. This called the absorption coefficient. The higher the coefficient, the more difficult it will be to seal the granite. To get an idea of how absorbent the granite is place several drops of water on the surface and time how long it takes for the water to completely disappear. If the water absorbs under one minute the granite is very porous; up to 3-4 minutes, consider it very porous; more than 3-4 minutes it is considered slightly porous. This simple test will also give a good indication of the amount of sealer needed to protect the entire area.
Finish:
The finish on the granite can affect its absorption coefficient. A polished surface will be less absorbent than a honed finished.
Location:
Where is the counter located? Is it in the kitchen, bathroom? What type of abuse is it exposed to? All of these have to be taken into consideration when choosing the correct protection product. For example, a kitchen countertop that is used daily will need a sealer that is oil repellant. For a guest bathroom that only gets occasional use then a water repellant sealer is acceptable.
Current Maintenance:
How is the granite maintained? If it's cleaned daily, it could be exposed to harsh chemicals. If maintenance is not done regularly, a granite countertop could have ground-in dirt and grit and any high polish could be worn.
How do I protect my granite countertop from staining?
There are hundreds of products to seal, protect and polish on the market today. Fortunately, all of these products fall into two major categories: coatings and impregnators (penetrating) sealers.
Coatings are sealers that place a "sacrificial" layer on the surface of the countertop. A film that lies on top acts as a barrier to prevent water, oil and dirt from entering the pores of the granite. The two types of coatings are strippable and permanent.
As it's name suggests, strippable coatings are those that are designed to be easily removed from the surface of the granite. This type of coating is made of polymers consisting of acrylics, styrene, polyethylene and others. They are usually water based. Most of them are designed for solid surface countertops and NOT for granite. If a coating is selected, be sure it is specified for granite.
Permanent coatings are very difficult to remove. They are made of solvent-based polymers such as polyurethane and epoxies. These are NOT recommended for granite.
Impregnators or penetrating sealers are designed to penetrate below the surface of the granite and deposit solid particles in the pores of the granite or to coat the individual minerals below the surface of the granite. This keeps water, oil and dirt from entering the granite.
Impregnators can be solvent or water based and usually contain silicone, siloxane, silane, methyl silicate or other silicon derivatives. The two types of are: hydrophobic(water repelling) and oilophopic (oil repelling).
Hydrophobic: designed to repel only water and waterbased chemicals. This type of impregnator would repel liquids such as fruit drinks, coffee, tea and soda
Oilophobic: this type will repel water and oil based liquids. Cooking oil, grease and body oils would be kept out of the granite.
An oilophobic impregnator will always be water repellant, but an hydrophoic may not be oil repelling. It is important to read labels to determine which type of coating is inside. Some products are listed as oil resistant.
Oil resistant products and oil repellant products are entirely different. Oil resistant will only slow the absorption of oil into the granite; repellants will keep the oil from entering at all.
How do I remove a stain?
Granite and natural stone are porous materials and this is why staining can happen easily. But it's also why stains can be removed-by reversing the staining process. Reabsorbing the stain into a different material (a poultice) does this. Poultices can be made with powdered whiting and hydrogen peroxide or a chemical reducing agent; it depends on the nature of the stain. Whiting is available in most paint stores. The poultice should be made and applied as instructed to remove the particular stain.
If the stain is deeply imbedded the poultice alone may not remove it. Some type of chemical solution will need to be added to dilute and/or react with the stain. When the poultice and chemical are applied, the chemical is absorbed into the granite, reacts with the stain and is then re-absorbed into the powdered/material.
Most stains can be sorted into one of the following:
-Oil based (grease, tar, cooking oil, food stains)
-Organic (coffee, tea, fruit, tobacco, cosmetics)
-Metal (iron rust, copper, bronze)
-Biological (algae, mildew, lichens)
-Ink (magic marker, pen, ink).
To identify the stain, determine what caused it. If the stain is near a plant, it might be that soil has leached iron (the stain may be brownish in color). The shape or pattern may be a clue-small droplet size spots near the coffeepot or splatters next to the stove would indicate organic or oil based stains.
Can I use marble on my kitchen counters?
Yes. In fact, marbles that have a honed finish will not etch because its surface starts out with a matte finish. Because marbles (and limestone and travertine) are calcium carbonate, the polished surface is more vulnerable to household acids including vinegar, mustard, catsup, citrus and a host of other food-related products. These acidic substances cause a chemical reaction which will remove the polish.
Additionally, marble and limestone can be scratched more easily than harder stones such as granite. Marble is, however, sometimes used in the kitchen as a pastry slab; its perfectly smooth, cool surface is ideal for rolling out dough and piecrusts.
What is marble?
True geological marble is limestone that has been subjected to great pressure and heat, which has changed its structure to a crystalline, sugary texture. It is generally white or whitish, sometimes translucent, with some veining or color provided by other minerals present at its formation. White Carrara, Thassos, Colorado Yule and Bianco Rosa are true marbles.
Commercially, the term "marble" applies to any compact limestone that will take a polish, which includes most of the colored marbles, except some of the greens.
How heavy is granite or marble and will my cabinets support it?
Granite and marble are roughly 6 pounds per square foot per centimeter of thickness. For example, a 2cm slab of granite weighs approximately 12 pounds per square foot and a 3cm slab weighs approximately 18 pounds per square foot. Any cabinet that is well constructed and properly set will support the weight of natural stone countertops.
