Flagstone is a natural stone and has a very porous texture. As a result, moisture can easily penetrate the stone surface.
The penetration causes stains, cracks, and other damages to the stone, ruining its natural beauty.
To keep flagstone pristine, you need to seal the surface using the best flagstone sealer. Several different types of exterior stone sealers and enhancers are available out there.
Silane-Siloxane sealers and acrylic sealers are the most popular used to preserve the natural beauty of this stone.
We have found the following sealers to be extremely effective in sealing the flagstone pores and keeping them from all possible threats. Let’s introduce you to each of them.
Quick Comparison: Best Sealers for Flagstone
Top 10 Best Flagstone Sealer Reviews:
1. Foundation Armor 5 GAL Acrylic Flagstone Sealer
Key Features:
- Type: Acrylic
- Base: Solvent
- Quantity: 5 Gallons
- Color: Clear
- Finish Type: Low Gloss with Wet Look
Though acrylic sealers are mostly used on concrete, you can use them to seal flagstone too. This sealer from Foundation Armor will give flagstone surfaces a distinct wet look and bring out their natural color.
As this sealer for the flagstone patio is solvent-based, it will effectively block the pores of flagstone to prevent oil or grease from penetrating the stone.
It will completely block moisture by creating a protective coating on the stone surface while not leaving any slippery film.
For this reason, this sealer will be suitable for both indoor and outdoor projects. High traffic or wet areas will be more secure with this sealer. The sealer also prevents abrasion of the stone surface.
An exterior flagstone sealer should be UV-resistant to keep the stone surface from yellowing. AR350 has excellent UV resistance to protect the surface.
The formulation of this outdoor stone tabletop sealer contains low VOCs to make it suitable for indoor projects.
Once applied, the exterior stone sealer and enhancer will strongly adhere to the stone surface. So, you don’t need to repeat the sealing process over and over again.
One coat of this sealer can protect flagstone surfaces for up to five years.
Pros:
- Breathable solvent-based sealer
- Excellent resistance to water, oil, UV, and other contaminants
- Durable protection with a natural wet look
- No need to use primer
- Easy application with low maintenance
Cons:
- Not feasible for small areas
- Has a bit of odor
2. Black Diamond Flagstone Sealer for Interior or Exterior
Key Features:
- Type: Acrylic
- Base: Water
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Gloss with Wet Look
Black Diamond sealer for flagstone patio is compatible with a wide array of materials, including concrete, slate, flagstone, etc. It has a water-based formula to make the sealer suitable for both interior and exterior projects.
The outdoor stone tabletop sealer comes in transparent color, so it won’t change the natural color of flagstone surfaces. Rather, it will enhance the color with a glossy wet look and retain the beauty for longer.
Being a water-based sealer, it makes flagstone surfaces more breathable than solvent-based sealers. It also gives better protection against moisture than its solvent-based counterparts.
The outdoor flagstone sealer will penetrate porous flagstone surfaces to create an invisible barrier and resist all types of contaminants. As a result, flagstone will remain free from stains, cracks, spalling, etc.
It also enhances the durability of the stone surface with its excellent wear resistance. So, you can use this sealer in high-traffic areas like pool decks, patios, etc.
Stoneworks outdoor flagstone sealer prevents saltwater or other chemicals from penetrating the stone surface.
The UV resistance is quite satisfactory as the exterior stone sealer and enhancer keeps stone surfaces from yellowing. One moderate coat can protect your beautiful flagstone for several years regardless of the weather.
Pros:
- Water-based formula for better penetration
- Low VOCs and toxic compounds
- Great coverage rate at about 500 sq. ft. per gallon
- Comes in convenient sizes
- Glossy look with natural color
Cons:
- Might not adhere equally to all surfaces
3. Ghostshield Siloxa-Tek 85001 Gallon Penetrating Sealer
Key Features:
- Type: Silane/Siloxane
- Base: Water
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Natural flat finish
Ghostshield siloxane sealer for flagstone is considered one of the best due to its high penetration capability. This sealer will penetrate stone surfaces to create a hydrophobic barrier.
As a result, the stone surface remains free from stains, cracks, and other threats for a long time.
The outdoor stone tabletop sealer is highly breathable, so there won’t be any film formation. No moisture will be trapped inside the barrier. For this reason, this sealer prevents mold and mildew from growing on flagstone surfaces.
As no moisture can penetrate the stone surface, freeze-thaw effects can’t crack the stone in extreme weather conditions. So, you can easily use this as an outdoor rock sealer.
Due to its water-based formulation, the odor will be very low. As a result, using this sealer for interior projects is also fine.
It gives flagstone surfaces a natural finish. As the finish is not too glossy, the protective coating won’t be visible on the surface. But it will continue to protect the surface from UV radiation. So, there will be no visible color change.
Use this penetrating enhancing sealer for flagstone to keep all threats out of the fence.
Pros:
- Highly penetrating silane siloxane sealer
- Protective coating resists water, oil, UV, and other contaminants
- Enhances the natural look of the stone surface
- Low VOC with minimal odor, so great for interior
- Dusting and abrasion-resistant
Cons:
- Can look too dull due to the finish
4. DOMINATOR 1 Gal. Color Enhancing Outdoor Flagstone Sealer
Key Features:
- Type: Acrylic
- Base: Water
- Quantity: 1 Gallon
- Color: White
- Finish Type: Satin finish
DOMINATOR is a great sealer for natural stone. Its water-based formula will be suitable for versatile surfaces, including flagstone, travertine, clay pavers, bluestone, etc.
Protecting flagstone surfaces from stains or cracks is one thing. But this blue stone sealer and enhancer even protect surfaces from chemical attacks, saltwater, and scratches. So, the natural beauty of the stone will be retained for years without any hefty maintenance.
Due to the water-based formula, it has lower VOCs and odor than the solvent-based sealer for the flagstone patio. So, you can easily use this blue stone sealer and enhancer for interior spaces like kitchens, washrooms, etc. It will give flagstone surfaces a distinctive satin finish that won’t deteriorate over time.
The sealer is highly resistant to wear, corrosion, UV radiation, etc. So, you can easily use it as an exterior flagstone sealer too. It has a great coverage rate which is higher than most other flagstone sealers out there.
This acrylic wet look flagstone sealer is breathable, so it will prevent organic growth on stone surfaces. The wet look of the sealer enhances the natural beauty of flagstone and sustains it for longer.
Pros:
- Highly penetrating water-based sealer
- Enhances the natural color of flagstone
- Resists water, oil, UV, organisms
- Low VOCs and odor
- Excellent durability with wear resistance
Cons:
- Might not suit all stones
- The coverage rate is low for very porous surfaces
5. StoneTech Salt Water Resistant Flagstone Sealer for Natural Stone
Key Features:
- Type: Penetrating Sealer
- Base: Water
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Natural Finish
StoneTech is a great outdoor flagstone sealer with great resistance to saltwater and UV. It is highly suitable for natural stones like flagstone and other surfaces, including masonry and grout.
The water-based formula of this penetrating sealer effectively seals the pores of flagstone to protect it from salt and chemical damage. It also prevents surfaces from yellowing by barring UV radiation.
So, you can use this flagstone sealer matte finish for outdoor projects like patios, pool decks, etc.
It dries clear with a natural finish which enhances the look for flagstone surfaces and sustains for several years. But the drying time is a bit higher than other water-based sealers.
The outdoor flagstone sealer comes in a one-gallon jar which can cover almost 500 sq. ft. But the coverage rate can vary according to the porosity of the surface. It contains low VOCs and has a very minimal odor.
StoneTech sealer remains breathable after penetrating the surface. It can prevent water, oil, and other contaminants from damaging the stone. Dusting and wear are reduced by a great margin after applying the sealer.
Pros:
- Retains the natural look of flagstone
- Prevents damage from saltwater and UV radiation
- Protects outdoor surfaces from discoloration
- Penetrates stone surfaces to seal them effectively
- Low VOCs and low odor
Cons:
- The coverage rate could be better
- Takes longer to dry and cure
6. EnduraSeal 100% Acrylic Solvent Base Flagstone Sealer
Key Features:
- Type: Acrylic
- Base: Solvent
- Quantity: 5 Gallons
- Color: Clear
- Finish Type: Semi-Gloss with Wet Look
If you are looking for a rock glaze sealant, EnduraSeal will give you the desired semi-gloss wet look with enhanced protection against several substances.
The solvent-based formula of this acrylic outdoor rock sealer creates an impenetrable barrier on the stone surface to protect it from damages caused by water, weather, etc.
Though it is named a concrete sealer, it will also work on natural stones like flagstone. It performs excellent for outdoor projects, protecting surfaces from degradation or discoloration.
The growth of organisms can also be prevented by applying this sealer on the flagstone. Though the manufacturer claims the wet look flagstone sealer to have a low odor, we found it to have a moderate odor.
So, it might not be suitable for use in enclosed spaces like kitchens or bathrooms. The coverage rate of this penetrating enhancing sealer for flagstone is also lower than most other sealers on our list.
One gallon of this sealer will cover only 300 sq. ft. at maximum. But it comes in a five-gallon jar which costs under two hundred bucks.
The price justifies the coverage rate, and it can be an economical solution for protecting flagstone surfaces from damage.
Pros:
- Suitable for a variety of surfaces, including flagstone
- Excellent weather and UV resistance
- Gives stone surfaces a natural wet look
- Protects flagstone from salt and chemical attacks
- Comes at a great price
Cons:
- The coverage rate is too low
- Has some odor
7. Foundation Armor Low Gloss Finish Flagstone Sealer
Key Features:
- Type: Acrylic
- Base: Solvent
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Low Gloss with Wet Look
Armor is a reliable brand in the world of sealers. This acrylic exterior flagstone sealer comes with a solvent-based formula that is high on penetration and effectiveness. It is mostly used to seal concrete and paved surfaces, but you can use it for flagstone too.
The stone armor sealer creates a breathable barrier between the stone surface and the weather. It has great protection against UV, so the surface won’t yellow over time.
AR350 also protects stone surfaces from water and salt damages, chemical damages, everyday wear, etc.
The freeze-thaw effect is one of the biggest threats to natural stones in extreme weather conditions. This stone armor sealer resists the effect of keeping your flagstone surfaces pristine for several years with just one or two coats.
The dullness of natural stone is diminished by the wet look flagstone sealer as it gives a natural wet look. No film is produced on the surface to make it glossy, so it can easily be used for indoor projects.
But you should consider the odor when applying indoors. Other than that, the top-notch performance of this flagstone sealer matte finish will keep you relaxed and stone surfaces protected.
Pros:
- Resists dusting, abrasion, daily wear
- Seals the look and color of flagstone
- Revives the dullness in stone surfaces
- Great protection against water, weather, chemical, etc.
- Five years protection with one coat
Cons:
- The coverage rate isn’t satisfactory
- Can have a bit of odor
8. Masonry Defender All Purpose 1 Gallon Flagstone Sealer
Key Features:
- Type: Silane-Siloxane
- Base: Water
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Non-gloss
Masonry defender concrete sealer comes with a water-based formula for great penetration into surfaces like brick, pavers, flagstone, and many more. You can use this sealer for natural stone for exterior projects like driveways, patios, decks, etc.
Its penetrating capability waterproofs stone surfaces and reduces the chance of freeze-thaw effects under extreme weather conditions. But no protective coating is formed on the surface, so you won’t see any film left behind.
As a result, the silane siloxane sealer for flagstone is highly breathable. No moisture will be trapped inside stone surfaces, which will keep the stone from cracking.
As it has a transparent color and no sheen in the final finish, it won’t alter the natural look of flagstone.
You can rely on this masonry defender concrete sealer to protect your flagstone surfaces for several years. The drying time is slower than other sealers, so is the curing time.
But the coverage rate was the reason for disappointment. It can cover less than 150 sq. ft. per gallon.
But still, it is an effective sealer with great water and weather resistance, which is the reason behind it being popular as an outdoor rock sealer.
Pros:
- Great penetration capability with unmatched protection
- Traps no moisture inside stone surfaces
- Suitable for an array of surfaces, including flagstone
- Completely repellent to water, oil, and other contaminants
Cons:
- Poor coverage rate
- Outdoor use only
9. AQUA-X Professional Grade Fast Dry Sealer
Key Features:
- Type: Penetrating
- Base: Water
- Quantity: 1 Gallon
- Color: White
- Finish Type: Natural Clear Finish
Increase the durability of flagstone surfaces with this AQUA-X clear penetrating rock glaze sealant. It seals the pores of flagstone effectively to block any contaminants damaging the look of the surface.
Its water-based formula contains low VOCs. So you can use it for interior projects along with all outdoor areas. It will cover up to 800 sq. ft. per gallon, which is a good coverage rate considering the price.
This sealer for natural stone is water-repellent, meaning it will block water or water-based substances from penetrating stone surfaces. As a result, stone surfaces won’t face cracking or pitting under harsh weather conditions.
Damage from other substances like salt or chemical will also be blocked by the sealer.
After application, the sealer gives a natural look to flagstone surfaces and sustains the finish for several years.
UV rays are downright harmful to stone surfaces, especially for outdoor areas. This sealer will keep flagstone surfaces from yellowing over time by blocking harmful UV radiation.
Investing in this sealer will be a wise decision if you want your flagstone to retain its character for longer.
Pros:
- Highly effective penetrating sealer with a water-based formula
- Great coverage rate even on porous surfaces
- Comes at an affordable price
- Quick-drying time with a natural finish
- Blocks water and other contaminants
Cons:
- Not suitable for a wide range of materials
- Temperate range should be moderate during application
10. Serveon Indoor/Outdoor Flagstone Sealer for Natural Stone
Key Features:
- Type: Penetrating
- Base: Water
- Quantity: 1 Gallon
- Color: Clear
- Finish Type: Natural Finish
This compilation of reviews ends with this premium rock glaze sealant from Serveon Sealants. You should get this water-based sealer to apply on many different surfaces, including flagstone, travertine, limestone, slate, and many more.
Its fast drying time amazed us. After applying the sealer for flagstone, the surface will dry to the touches in just one hour.
That will be really helpful for high traffic areas. So, you can use this sealer for driveways, patios, pool decks, showers, etc.
This sealer for natural stone has a deep penetrating capability to block the pores of flagstone and make the surface water-repellent.
As a result, no moisture can penetrate the stone surface and cause pitting or spalling in the stone.
It also protects stone surfaces from salt and chemical damage. The look of flagstone surfaces won’t deteriorate over time due to UV radiation or dusting as the sealer creates an impenetrable barrier.
Where many sealers leave a visible film behind, this sealer will dry clear and give a natural finish to your stone surfaces.
This finish will sustain for three to five years before you need to seal the surface again.
Pros:
- Deep penetrating sealer with high protection
- No slippery film is formed after application
- Has a fast drying time
- Applicable to a variety of surfaces
- Low VOCs with low odor
Cons:
- The coverage rate could be better
Best Sealer for Flagstone Buying Guide
Keep these factors in mind before choosing a quality flagstone sealer.
Type
Flagstone sealers come in many different types. Acrylic and Silane-Siloxane paver sealers are the most common types and are highly popular among expert professionals for sealing flagstone.
Some of these paver sealers will come in a water-based formula, while others are solvent-based.
Water-based sealer for flagstone contains low VOCs and have low odor, so they are more suitable for interior projects.
Protection
As the primary purpose of sealing flagstone surfaces is to enhance their durability, the sealer you choose should give all-around protection.
Some sealers are great against water, salt, or chemicals but can’t fight weather so much.
Always go for a sealer that has an impeccable ability to protect the stone surfaces from any threats out there, including UV radiation.
Finish
This depends mostly on the user’s personal preference. Some like a high gloss finish, while others go with a satin or natural finish. The finish of the sealer for flagstone shouldn’t scream like a sealer is there.
It is more to be hidden on the surface so that our eyes can enjoy the natural beauty of flagstone. Natural finishes with a bit of a wet look are better in terms of aesthetics.
Drying Time
It is crucial to apply a sealer that dries faster. If you need to wait for a long time after the application, it might be inconvenient, especially for high-traffic areas.
Most paver sealers have a drying time of about 6 hours, and they need an additional 24 hours for curing.
Try to cut down this time to one hour or so.
Coverage Rate
Know how much area a sealer for flagstone can cover before buying. The coverage rate can vary according to the porosity of the surface.
Flagstone surfaces are moderately porous, and they will need a good amount of sealer to cover a certain area.
You should go for a sealer that can cover at least 400 sq. ft. per gallon. Anything lower than that might not be a worthy investment.
Odor and Toxicity
Solvent-based paver sealers contain high VOCs. These compounds emit gases with high odor, which might not be suitable for use in enclosed spaces.
You can select water-based sealers for such areas. Those sealers will have a lower odor than solvent-based sealers.
Durability
If you need to reseal the stone surface every six months, there’s no point in buying the sealer. A good sealer should protect the surfaces for at least three to five years before resealing.
As this is also subject to the usage of the surface, you should go for a sealer that has higher durability.
A good sealer should protect the surface from deterioration even under all possible threats.
Why Should I Seal Flagstone?
As you might already know, flagstone is a natural stone with moderate to high pores. Water can easily penetrate the stone surface and cause permanent stains, which ruins the look of the stone.
Other than water, several substances can damage the surface, including oil, salt, and other chemicals. Often, water contains different minerals that can also damage flagstone.
This is why sealing flagstone is necessary to protect the natural beauty of the stone. By sealing the pores of flagstone, the surface becomes repellent to water and other contaminants.
Paver sealers create a protective layer on the surface to keep it from dusting or chipping.
Besides, flagstone surfaces can yellow over time due to the effect of UV rays. A good flagstone sealer will protect the surface from discoloration and enhance the natural look of the stone.
So, you need to seal flagstone surfaces right after completing them.
How to Clean Flagstone Before Sealing?
Before you apply any sealer for flagstone, they need to be thoroughly cleaned. Otherwise, some dirt or debris might remain that will be trapped inside the sealer. This can later reduce the effectiveness of the sealer.
Let’s get over a few simple steps to clean flagstone surfaces before sealing.
Things You’ll Need
- A large bucket
- Dish soap
- Brush
Step 1: Make the Cleaning Solution
Pour dish soap into a bucket of water and stir it to dissolve completely. Don’t use an abrasive cleaner to clean flagstone surfaces. It will do more damage to the surface than good.
Step 2: Scrub the Surface
Take a scrubbing brush and dip it into the solution you have previously made. Start scrubbing the stone surface moderately from one side.
Make your way towards the outer side gradually. Remove any remaining dirt or debris carefully.
Step 3: Wash the Surface
Give the surface a final wash with clean water. You can also use the pressure wash method to deeply clean the surface.
Step 4: Let It Dry
After washing the surface, let it dry completely. Don’t apply sealer on a wet surface. Otherwise, the sealer might not adhere to the surface properly.
How to Keep Your Flagstone from Peeling?
Flagstone surfaces are susceptible to peeling, chipping, and other damage. The main reason behind peeling is everyday wear. As the surface becomes loose, it might come off with a bit of force.
So, follow these steps to prevent your flagstone from peeling.
Step 1: Reduce Chemical Exposure
Flagstone used near pool areas or other saltwater sources might be vulnerable to peeling. This happens due to the chemical reaction with chlorine and other substances.
Make sure you are sealing the surface properly so that it doesn’t come in contact with salt or other chemicals.
Step 2: Remove Smaller Peels
Whenever you see the symptoms of peeling, try to remove the peeled part of the surface as soon as possible. If you let it sit for longer, the peel will expand.
Step 3: Clean the Surface and Seal It
After you clean the peels, give the surface a wash and use a good sealer to protect the surface from peeling.
Pros and Cons of Sealing Flagstone
Before you seal your flagstone surfaces, know why you should and shouldn’t do it.
Advantage of Sealing Flagstone
For these reasons, you should seal flagstone surfaces.
Durable Protection
Flagstone sealers create a protective barrier to block all contaminants. As a result, water or other substances can’t stain the surface. This protection sustains for years, depending on the quality of the sealer.
Prevents Organisms
If moisture penetrates flagstone surfaces, it might cause mold and mildew to grow inside the surface. Sealing flagstone will prevent these organisms from growing.
Prevents Pitting, Spalling, Thawing
Damages caused by de-icing of salts or freeze-thaw effects can be minimized by sealing flagstone surfaces.
Protects Natural Look
Sealers often come in a clear finish which enhances the natural look of the stone. Some sealers have a wet look to remove the dullness of flagstone surfaces. UV protection ensures the surfaces don’t yellow over time.
Cons
Remember these points before sealing flagstone surfaces.
Moisture Can Be Trapped
Some sealers aren’t breathable. If the stone absorbs water from beneath the surface, the vapor won’t escape the stone, and it can then cause cracking.
Surface Can Be Slippery
Some sealers leave a glossy film behind, which can be slippery, especially if the surface stays wet most of the time.
How to Seal Flagstone Indoor?
Sealing indoor flagstone surfaces might seem no different than sealing outdoor but you need to take some extra care. Here are the steps you can follow.
Step 1: Clean the Surface Properly
Outdoor surfaces having some dirt might be tolerable, but indoor surfaces should be thoroughly cleaned. Give your target surface a deep wash using a pressure washer.
Step 2: Choose the Right Sealer
You can’t just use any sealer for indoor projects. Choose something that has a water base so that it has a low odor. Using solvent-based sealers for indoor projects won’t be a wise idea.
Step 3: Apply the Sealer
Seal the surface in long strokes. Make sure the sealer covers the whole surface to enhance protection.
Step 4: Let the Surface Dry and Cure
It might take some time for the surface to dry completely. You can apply a second coat if needed. Allow it at least 24 hours to dry and cure.
FAQs
Enough of discussions; we are going to answer some of your frequently asked questions now.
1. How Often Should you Seal Flagstone?
This depends on several factors. If you are talking about a low traffic area, it will take less wear than high traffic areas. And sealing intervals can vary depending on the quality of the sealer, too.
A general rule is to seal flagstone surfaces every three years. Some sealers can protect the surface for five years.
2. What are the Sealers Made Of?
Sealers can be made of different compounds, including silicone, acrylic polymer, polyurethane, etc.
Depending on the base of the sealer, other compounds are added to the formula.
Acrylic or Silane-Siloxane, both sealers can be solvent-based or water-based. Solvent-based sealers contain high VOCs, while water-based sealers are low on VOCs.
3. How Much does it Cost to Seal Flagstone?
It depends on the sealer you are choosing. Flagstone sealers come at different prices. Usually, you will get one gallon of sealer at 100-200 bucks depending on the quality.
Flagstone sealers cover approximately 500 sq. ft. per gallon depending on the porosity of the stone.
So, it will cost 20 to 40 cents per sq. ft. on average. Including other costs, you might need to spend more than 50 cents per sq. ft.
4. How to Identify the Best Sealer for a Natural Stone?
When picking a natural stone sealer, you should check whether the sealer can prevent stains, pitting, cracking, freeze-thaw effects, etc. It should also be UV-resistant. And there should be no slippery film on the surface.
Final Thoughts
Flagstone sealers can really go a long way to protect your favorite surface from any possible threats over the span of years.
Be it your kitchen, shower, or pool deck, these sealers block the pores of the stone and prevent them from stains and other damages.
But choosing the right sealer is utterly important. This is why we suggest you use the Armor AR350 Acrylic Sealer to protect your flagstone surfaces. It is a great solvent-based sealer to block any contaminants from penetrating the surface.
The UV resistance of this sealer is excellent. And it enhances the look of your patios or pool decks with a natural wet finish which sustains for a long time.
Give the best flagstone sealer a try to protect that stunning flagstone from damages.