Stone Sealers - Should I seal my stone?

Stone Sealers:  Should I seal and/or clean my stone?

            You have made an investment in one of nature’s most beautiful products and it’s important to know how to care for your material.  Oftentimes, we are asked if natural stone should be sealed.  The answer to this question is easy, YES!  Although some contractors will tell you that it is not imperative to seal stone, it is a good idea to do so.  This article will explain why sealing natural stone is important, how to pick the appropriate cleaners and sealers, and also answer some common questions.

            To determine what type of sealer you will need, first you need to identify the type of stone you have and to understand it’s composition.  Apex Stone™ sells a variety of types of natural stone including limestone, sandstone, travertine and cantera.  Limestone and sandstone are both sedimentary rock which make them a porous stone.  Travertine is a type of limestone and generally has naturally occurring voids on the surface created by water elements and pressure over time.  Some customers choose to fill these natural voids while others leave them unfilled.  Cantera stone is a volcanic material composed of quartz-based minerals. 

The next key factor in determining which sealer to choose is to consider the application of the stone.  A vertical application, like the façade of your home or a door or window surround, may not have as many opportunities to stain as a horizontal application like a flagstone or travertine patio.  Stone on the exterior of your home should still be sealed to assist in repelling water and other precipitants.  Natural stone absorbs moisture and is constantly expanding and contracting depending upon the amount of moisture absorbed.  Over time, this expansion and contraction puts stress on the mortar joints and could result in abnormal cracking or shifting of the joints and/or stone.  In addition, sealing the stone on your home will aid in the resistance to efflorescence and staining from irrigation systems.  For an application such as a flagstone or travertine patio, sealing is important because generally these areas are high traffic areas and the potential to experience spills and stains is relatively high.

We have now identified what type of stone is being used (limestone, sandstone, travertine or cantera), and where this stone is being installed (on the façade of the home – vertically installed or horizontal installation like a patio stone).  Now let’s talk about what sealer and cleaner are best for your stone.

Before natural stone is sealed, it is highly recommended to clean your stone.  Because of its’ porosity and rapid absorption, experts do recommend using a cleaner specifically formulated for natural stone.  Picking the correct cleaner is key to minimizing the risk of damage to your stone.  Apex Stone™ carries three (3) cleaners designed for natural stone.

  • Stone & Tile Cleaner Concentrate – used as an overall cleaner for interior and exterior stone. 
  • KlenzAll™ Cleaner Concentrate – Heavy duty water-based cleaner – Alkaline formula
  • Restore™ Acidic Cleaner Concentrate – Heavy duty water-based cleaner – Acidic formula – not recommended for Limestone or Travertine.  Useful for hard water deposits, grout haze, efflorescence and soap scum

Once you have cleaned your stone, it’s now time to choose a sealer to protect your investment!  There is a MYRIAD of options when choosing a stone sealer.  Apex Stone™ carries seven (7) types DuPont StoneTech® Professional Sealers which are design specifically, and safe, for all the types of stone we sell.  Each of these products will seal and protect your stone from weather, staining and normal/expected spills and stains.

  • Heavy Duty Sealer – Water-based – indoor/outdoor
  • Heavy Duty Exterior Sealer – Solvent-based – outdoor
  • Impregnator Pro® Sealer – Solvent-based – indoor/outdoor
  • BulletProof® Sealer – Water-based – indoor/outdoor
  • Natural Stone Countertop Sealer – Water-based – indoor/outdoor
  • Salt Water Resistant Sealer – Water-based – indoor/outdoor  *(ideal for Coastal homes or coping and patios around a Salt Water pool)
  • Enhancer Pro™ Sealer – Solvent-based – indoor/outdoor – will enrich color

All of the sealer’s Apex Stone™ carries are impregnator sealers, which means the liquid sealer will be absorbed into the stone.  Some sealers, like high gloss or matte finishing sealers, are designed for non-porous stone, or stone that has been polished.  These sealers are not absorbed into the stone; rather a topical coating.  Apex Stone™, at this time, has chosen not to carry these products but we do have access to order them if a customer shows interest.

Finally, let’s cover some commonly asked questions!

Q:  How often do I need to seal my stone?

A:  This depends on how much traffic, or wear and tear, the area receives.  With properly applied sealers, the average time frame is 3-5 years.  However, with high traffic areas, it is not unheard of to reseal every year.

Q:  What stains will my sealer protect?

A:  Stains are broken into two (2) categories – water-based and oil-based.  Cola, orange juice, tomato sauce, jelly are all examples of water based stains.  These types of spills/stains can generally be cleaned with a water-soluble cleaner.  Oil-based stains usually require a solvent-based cleaner.  Examples of oil-based stains are cooking oil, hand cream, shampoo and peanut butter.  If you are unsure which product to use on a specific stain, please contact their help number at 800-243-4788.

Q:  How do I know if my stone is already sealed, or needs to be re-sealed?

A:  If you put a drop of water on the stone and it beads off, then your stone is sealed and does not need to be re-applied at this time.

Q:  How much sealer do I need to buy?  How much surface area does it cover?

A:  The answer to this question is not a simple one.  Each product is going to cover a different amount of square footage or surface area.  Each type of stone will absorb a different amount of sealer depending upon the porosity of the stone.  Whether your stone is polished or raw will also affect the absorption rate.  Please refer to the Technical Data Sheet on each product for more information.

Q:  Does a professional installer need to apply my sealer, or can I do it myself?

A:  All of the products that Apex Stone™ carries are friendly for the do-it-yourselfer.  Unlike other products, all of the Dupont™ products we carry are applicable with a sprayer.  Just remember to refer to the instructions and follow them carefully.  Dupont™ also has a toll-free number to contact with more detailed or specific questions.  Please contact them at 800-243-4788.  Or you may visit their website for further details!