Do Limestone Pavers Need to Be Sealed? (Why It’s Important!)

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Do Limestone Pavers Need to Be Sealed?

The use of limestone pavers, rather than concrete, for your pool deck will certainly cost you a lot more. But it is worth it! Limestone pool decks have classic natural beauty and are more durable than concrete. But, do limestone pavers need to be sealed?

Limestone pavers need to be sealed to protect them from stains, chemical corrosion and abrasion. Use penetrating sealers or topical sealers with non-slip additives to prevent sealed limestone from becoming too slippery.

Limestone is quite a porous natural stone, though not as porous as travertine. The porosity of limestone is a useful property for pool coping and pavers around the pool. Porosity keeps limestone pavers from becoming slippery when wet.

Unfortunately, porosity also means that limestone pavers readily absorb water which is often contaminated with mildly corrosive chemicals. The source can be pool chemicals, household cleaning products or even mild acid in rainwater.

Due to its porosity, spills of wine, juices or sauces penetrate quickly and deep into limestone pavers. These are then extremely difficult to remove.

4 Popular Stone Pavers

Limestone pavers are quite popular as decking material around pools. Travertine, Granite and Marble are the other common stone pavers used around pools.

While all four are natural stones, they differ from each other. Each went through a different geological process, under the crust of the earth, eons ago. Geologists classify most of the rocks as sedimentary, metamorphic or igneous.

• Limestone is a sedimentary rock and is mostly composed of calcite from biological activity. Limestone was formed when the shells of marine organisms deposited on the ocean floor and compressed by layers above.
• Travertine is also a sedimentary rock and is mostly composed of calcite from volcanic activity. Travertine was formed when rivers rich in minerals or hot springs evaporated and the residue was compacted by layers of earth above it.
• Marble is a metamorphic rock and is mostly composed of calcite. Marble started off as limestone. Limestone buried deep into the earth, changed from a sedimentary rock to a metamorphic rock under severe heat & pressure, to become marble.
• Granite is an igneous rock and is mostly composed of silica (quartz) and alumina. In composition it is different from the three above. Granite was formed when hot molten magma within the earth’s crust cooled and solidified. 

Rocks.CompareNature describes limestone as “less porous” and travertine as “highly porous”, when comparing the porosity of the two. But limestone is certainly more popular than marble or granite.

Limestone pavers need to be sealed to block the pores. Sealing makes limestone pavers more durable, stain resistant and weather resistant.

What Happens If Limestone Is Not Sealed?

Limestone pavers that are not sealed will not be able to retain their initial beauty for long. Much of the damage caused will be permanent and can not be reversed. The value of your investment will drop. This will be reflected in the valuation of your home, should you want to sell it.

Unsealed limestone pavers will

1. Get dirty & stained easily
2. Fade & lose color very fast
3. Be worse for wear & tear
4. Corrode & degrade early

Dirt & Stains

Limestone pavers used around pools are both textured & porous. This is very helpful as it improves traction and readily absorbs water from the soles of wet feet. The result is limestone pavers are less slippery.

But texture & porosity of limestone pavers is a double edged sword.

Texture traps more dirt & grime than a polished surface. Spills of red wine, orange juice or BBQ sauce penetrate easily into the paver. Since the stain penetrates the limestone, it is near impossible to get it out!

Fading & Discoloration

Limestone pavers used on pool decks are generally light pastel colors. White, Cream, Beige, Sand, Light Gray are popular. However, deeper tones such as Tan, Coffee, or Rust are also used. Whatever the color, limestone always has veins, streaks or specks.

If the limestone pavers are not sealed, the bright earth colors will fade rapidly under the harsh UV radiation of the sun. The deck will look washed out and bleached. 

Quite different from the original vibrant lively color!

Scratching & Chipping

Limestone pavers are hard & tough but not as hard & tough as granite pavers. Bare foot traffic may not damage the pavers, but movement of deck furniture (chairs, recliners, umbrellas) and pool equipment (vacuum cleaners, pumps) could result in scratching & chipping.

Limestone pavers need to be sealed to protect from normal wear & tear!

Corrosion & Degradation

Limestone is mostly made of calcite. The chemical name of calcite is calcium carbonate. Even mild acids will react with calcium carbonate and break it down. Mild acids are present around the pool in abundance.

Chlorine is the most common chemical used to sanitize pools. Chlorine combines with the pool water to form hypochlorous acid, which kills pathogens in the pool. Pool water that falls on unsealed limestone paver will penetrate it and corrode the calcite from within.

Have you heard of acid rain? Rainwater can contain small amounts of sulfuric acid or nitric acid due industrial or other types of pollution. Acid rain has the same corrosive & degrading effect on limestone pavers as hypochlorous acid from the pool. 

What Do You Seal Limestone With?

There are three types of sealers that can be used on limestone pavers.

Enhancing Stone Sealers:

Enhancing Stone Sealers penetrate and bring out the natural vibrant colors locked within limestone. Enhancing sealers also protect limestone pavers from staining and acid discoloration. 

Refresh your older limestone pavers by applying a coat or two of Black Diamond Color Enhancer Sealer

Impregnating Stone Sealers:

Impregnating Stone Sealers are purely functional. Like enhancing sealers, they penetrate into the pores of the limestone paver, solidify and block them. Water, stains or harmful chemicals can not enter the pores.

Impregnating or Penetrating sealers protect the limestone pavers without altering their natural texture & appearance. 

It is ideal for new limestone pavers for the pool coping and near the pool. The slip resistant property of the limestone paver is retained. Penetrating sealers will be stain resistant to a degree as the stain will not be able to penetrate the pores (already blocked by the sealer). 

I recommend Miracle Sealants 511QT6 511 Impregnator Sealer. It is very effective at protecting against water, stains & slippage.

Topical Stone Sealers:

Topical Stone Sealers penetrate a bit, but mostly form a glossy or egg-shell, protective film on the limestone surface. They impart a rich lustrous look to the limestone paver and will make it stain resistant. 

For a wet look I recommend Foundation Armor AR350 Solvent Based Acrylic Wet Look Concrete Sealer. However, topical sealers smoothen out the texture of the limestone making it slippery.

If you expect the sealed area to be wet most of the time, then better add a non-slip additive to the sealer. There are several popular brands such as SureCrete’s SureGrip, H&C SharkGrip or Matcrete’s Rhino Grip.

Thank you very much for reading the post. I do hope you found it informative and helpful.