Devin Devine, stone mason based in Pennsylvania, projects across the country
devin@devineescapes.com
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Sealing a flagstone patio
I keep receiving comments on my blog about sealing flagstone, and the question keeps coming up during DIY consultations, so I figured this would make a good edition of “Ask Devin”. Do you have a DIY hardscape project such as a flagstone patio? Feeling like you could use some professional guidance? DIY hardscape consultation services available! TL writes:
Hi Devin, I live in north east Ohio and came across your website when I was researching flagstone patios. I did not see any comments or suggestions on your website regarding sealing flagstone, so I thought I would send you an email . My wife and I bought some flagstone from a local supplier a few years ago to build a patio. The flagstone was gray and orange in color and had a really nice patterns.
We are not experts in laying flagstone, so we hired a landscaping company to install the flagstone for us and provide expert advice. He suggested using polymeric sand between the stones, and also recommended putting a sealer on the patio that would protect the stone, and also give it a “wet” look.
They did the work in late fall. Laid the stones, filled in the spaces with the polymeric sand, and then sealed the whole patio. They were most of the way complete, and just needed to come back in the spring to install the edging and put a final coat of sealant on the patio. Since we personally knew the landscaper, we paid him in full for the project, and expected him to come back in the spring to do the final steps.
When spring came and all the snow was melted, we went outside to see how the patio looked. To our horror, the stones were ruined.
The nice patterns and colors that the stones had were all peeling off. Therefore we contacted the landscaper, and his immediate response was that we had “bad” stone. I never heard of such an expression. How can stones be bad? The landscaper never provided any further explanation of what “bad” stone was. He was supposed to come back and pull up the stones, so we can get them replaced, and then was going to lay a new patio for us (without sealing it).
To make a long story shorter, he never came back out. I ended up pulling all the stone up, and putting in a new patio all by myself. The landscaper told us that he filed a claim with his supplier and that we would get a full refund due to the sealer being no good. Do you have any experiences like this?
Can a sealer destroy the color and look of flagstone? Attached are a few pictures we took after we found the stones ruined. In some pictures you can even see that the landscaper did not do a good job cleaning off the stones before sealing them, since the polymeric sand is sealed on the stone in some areas.
I would love to hear your thoughts and experience in this area, and if you agree that our conclusions make sense. The sealer was no good and/or the landscaper did not properly clean off the sand before sealing the stone. Thanks!
Sealing flagstone is not recommended.
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With any grade-level masonry, if you seal the top, then you potentially trap in moisture.
Water can still get into the stone through the bottom of the stone, but now it has no way to evaporate, because the top is sealed. Polymeric sand is not the best thing to use with flagstone, either. Looking at the photos you sent me…..there’s spaces between them flagstones that look a good 10″ wide. I guess he decided to put a little bit of flagstone in-between the polymeric sand.
As a professional, I have not sealed a flagstone in many years, for reasons of not wanting to trap in moisture. The old answer, that I always used to give is “do not seal flagstone…..but if you really must insist on sealing it, then use a matte finish. A glossy finished product is more likely to create a slippery surface”.
Essential tools needed for flagstone installation:
- Grabbo lift flagstones without difficult prying. Save your fingers! If installing less than 100 square feet–don’t bother. If installing more than 200 square feet–buy 2.
- Wood handled brick hammer. Happens to cost less than steel….but I prefer wood, less jarring on the elbow.
- Dead blow mallet. This one will do, if you’re only using it for one job or so…buy a fancier one, if you’re learning this for your career.
- https://amzn.to/3ksajx9 Angle grinder. Same one I use.
- https://amzn.to/2VYb8Ey Blades.
- https://amzn.to/3hU8hoa Brick chisel.
- https://amzn.to/3ktol1G Grabo. Not cheap, but it will save your finger tips from having to pry up heavy stones. Worth it, if you plan on laying more than 200 square feet (or so) of flagstone.
- A couple of 5 gallon buckets (for stone dust, when leveling stones)….shovel, wheel barrow…..4′ level
- https://amzn.to/3hWi0tR Pick maddock. Best way to dig. Break up soil with this, then use shovel.
- https://amzn.to/3lFjfPi Knee pads–essential.
Related articles, DIY and hardscape how-to:
- what to use for under flagstones, concrete, sand, gravel, or what?
- what to put between your flagstones sand, mortar, polymeric sand…..or stone dust?
- how to manage weeds on your stone patio
- replacing the cement between flagstones, re-pointing
- how to clean your flagstone patio
- DIY hardscape consultation services–professional guidance on “how to build your own flagstone patio”
- how to build a dry stone wall
- how to cut flagstone with a hammer
- Grabo vacuum lifting tool review
- CHECK OUT my stone art (and share on your social media) too!
UPDATE
Based on a conversation had below, in the comments, I’ve come across this product on amazon. The product claims to be:
- Water repellent characteristics help to reduce deterioration caused by water absorption and freeze-thaw cycles
- Will last for up to 3-5 years before the need to reseal
- Breathable, low VOC, single coat application.
So this is what I mean when I say “do not seal flagstone….but if you do, then use something matte”. This product claims to be breathable–that’s the key word. What we’re being led to believe here is that the product will repel water from entering stone, but it does not create a water-proof film and all-importantly, that it does BREATH. If it breaths, then moisture (allegedly) won’t get trapped.
I’m still cautious and skeptical on the matter. Chances are I won’t be using this product myself, any time soon, preferring to keep things as natural as possible,
Not a professional installation. These wide gaps might be acceptable if you had some sort of gravel in between the flagstones….and if the job were being done by a home owner (or a landscaper). With gaps that wide your polymeric sand is guaranteed to crack. The manufacturer may claim that their poly-sand is good for gaps up to 2″ wide. Again and again however I see that that is not the case. 6″ to 10″ wide gaps? No way.
I recommend:
- 6″ of compacted roadbase type gravel (3/4″ minus crushed stone)
- Stone dust (1/8″ minus, or 1/4″ minus) as both leveling agent and joint filler
Effects of sealing flagstone
stone peeling up, don’t seal flagstone
Flagstones are usually sedimentary stone, that is built up in layers. The layers are often different colors… It seems that what happened is the stones absorbed groundwater from below, and could not evaporate. Then freeze-thaw came along, and that moisture that was trapped just below the stone’s surface went and froze, causing the topmost layer to flake up, peel off, delaminate, or spall. Hence, the beautiful colors of your flagstone were ruined.
But you also asked “can stones be bad”?
(I do not believe that this is what happened to your flagstones, but to be complete I’ll have to include this final paragraph)
Stone quality may vary. For one flagstone walkway, that I built a decade ago, the stones that we purchased had visible cracks along their edge. Like a book, flagstone is (often) built up in layers. If you look at the edge of the stone, you may be able to detect these layers….well, for this one project, our stone showed up, and a good half of the stones had obvious faults–if you looked at the edge of the stone, it looked like the “book” was starting to open up. An inch and a half stone was looking ready to be peeled apart, with a visible seam somewhere in the middle. So I had to purchase tones of extra stone, and got rid of most of the old, faulty stone. But ultimately, we had to use what was available. Got rid of the worst, kept the best, bought in some new stuff and got it done.
The problem came next spring, and I had to return to replace a few (might have been 8 or more) flaked up stones. Lesson learned!
And that was a bummer! The stones weren’t flaking up in paper-thin layers like yours did, rather they were cracking in the middle, so the top 1/2″ of a stone would peel off. I learned a painful lesson….having already purchased twice the amount of stone as the job originally called for, I then had to return a year later and work for free for a day. Worse still, 2 years after that the customer called again. This time it was only 2 or 3 stones. This was a decade ago and happily, none of my walkways have had trouble like that since then and going forward I know: don’t risk laying a stone that looks like it’s ready to peel apart.
Final word on sealing flagstone
So I’m sorry this happened to you and your patio! I can’t say for absolute certain that the sealant is what caused this failure. But it is not recommended to seal flagstone– and if a flagstone did fail because of sealing…then your photos are exactly what I would expect the failure to look like. Paper-thin layers, peeling up.
Good luck with your new stone patio!
consultation services
…..this is the perfect time to tackle that DIY flagstone/hardscape/dry stone wall project that you’ve been dreaming about doing on your own. But where to start? Wouldn’t it be totally awesome if a professional with over 23 years experience in this field was available to guide you, and talk you through the entire process, answering any site specific questions you may have? The response has been overwhelmingly positive. Email devin@devineescapes.com
Hi Devin,
Thanks for your reply and expert advice. Obviously the landscaper we used was not as experienced as he claimed to be with flagstone, since he provided poor guidance.
We did this project a few years ago, and we got new flagstone since the stone was ruined by the landscaper. This time we used a lilac stone, created smaller gaps, and put pea gravel in between the stone. We did not want to risk having problems again with the gray/orange stone again, and liked the color of the lilac. The lilac stone has been down
for 2 summers now. Well since we have dogs, the pea gravel goes all over the place, and my wife does not like it. I will look at the stone dust and see if that works better.
Also, I noticed this spring that the lilac stone on the patio did not have the same nice strong color it originally had. I kept some left over lilac pieces under our deck and took it out to compare to what has been on the patio. When I compared the stone that was under our deck to the lilac stone on the patio I noticed that the patio has faded to an almost blue or gray stone. Is this normal for lilac stone to fade like this? Is it from exposure to the sun/elements etc.?
Thanks,
TL
TL
You’re welcome.
Yes, i use a lot of lilac flagstone, which is a type of Pennsylvania bluestone. The material i use is, anyway. And yes, bluestone does sometimes patina…into a dingier, duller color. Usually if the patina is really bad, this is because of too much shade and/or too much humidity. Algae or mildew will form. It’s a matter of preference if this is a “bad thing”.
I have a customer with a well shaded patio, that lost a lot of it’s luster over the years…the customer doesn’t mind though, and has declined offers to have it powerwashed. Shaded situations also tend to cause moss to grow in the joints–which this particular customer loves. Again, it’s a matter of preference.
Pea gravel is terrible, for patios/walkways. One time, i had a client who really really wanted river pebbles in the joints–so i cautioned against that, but then decided we could use 1″ to 1.5″ river rocks, instead of smaller pebbles. Took a couple hours to fill the joints this way, on a 300 or 400 sq ft walkway, as the pebbles had to be placed, rather than just broomed into place.
I’d go with stone dust myself.
Cheers,
Devin
I do have 1 more issue that I’ll ask about. I power washed my stone and to my embarrassment I cut holes in the stone. Not much, but I have 2 r 3 stones that I’d like to replace…minimally, cut back and patch in with another smaller stone. How difficult is this to do? I’m no mason but I can handle a hammer. Is this simple enough for me to handle? Businesses want $1500 to regrout my patio…insane when I’m sitting here doing nothing. But – I need direction thank you very much for your information.
How difficult…..I have no idea how to rate it, but with proper instruction I think you could handle it. You’ll need an angle grinder with diamond blade though, in order to cut out part of the broken stone, without busting the stone loose.
This article should help with the re-pointing:
https://www.devineescapes.com/replacing-the-cement-between-flagstones/
This one for stone cutting, though since your patio is mortared in you will also need some sort of diamond blade:
https://www.devineescapes.com/how-to-cut-flagstone-using-a-hammer/
Our flagstone is 8 years old and is starting to flake and chip, never been sealed.
This is unfortunate. But sealing is not the only reason why flagstone may flake and chip…..are you in a northern climate? If so, do you allow the snow to melt and re-freeze over and over? It’s better to have that flagstone shoveled, every now and again. Of course most of my customers are in Pennsylvania and New York, and who knows what percentage of these patio owners bother to shovel off a hardscape that they are not currently using because it’s winter? Let’s say half. Anyway, to date I’ve only heard one customer complain of stones flaking or chipping up–and that client received a bad batch of stone. I had to replace many stones, at my own expense.
Another thing to note….you say stones are flaking. Well, what sort of stone was used? Pennsylvania bluestone, or New York bluestone, may have small chips of the natural cleft surface that come off. A small chip here and there over years, on a 1000 sq ft hardscape, shouldn’t be much of a bother. If the flaking is excessive, messy, a trip hazard, or just making the hardscape not look so pretty anymore……then I wonder–did you get a bad batch of stone?
Sorry to read of your troubles. Post a photo here (using imgur or something) if you want me to attempt a more informed diagnosis.
Oh and a final thought–is the joint material/bedding material well draining? Polymeric sand and mortar can both cause problems, when used in a dry laid flagstone project. And is the patio pitched properly, to shed water?
We bought a house a year ago in Maryland (suburban Washington, DC) that had an existing dry-set flagstone walkway. We don’t know the age of the walkway, but many of the stones (which all appeared to be in good condition) had settled and tilted, creating trip hazards. We had the walkway power-washed and reset.
One of the stones has recently developed paper-thin delamination. Can anything be done to stop the delamination, and prevent it from happening on the other stones??
From what you’re telling me, this is probably a bluestone patio. Most flagstone that you see in Maryland is bluestone, and blue stone can delaminate. I’d pull the stone out and stand it up on edge, looking at the edge of the stone. Does it look like a book, and you can see the individual pages, some of them beginning to open? If so, the entire stone is compromised. If it’s only the very top most page or two that is starting to separate, then I’d take a chisel and remove those loose layers. Might get another decade or so out of it.
How this happened: some stones are just ready to crack open. I’ve seen 50 year old patios where the stone is all holding up good, and I’ve re-built 50 year old patios where every stone was either starting to delaminate, or about ready to (meaning the stones looked good, until I pulled them out and saw the edge and saw that they book was ready to open). Also, the walkway was off-level, as you describe it, and that caused water to sit in places. So if the stones have been re-leveled, hopefully they are done in such a way that there is no puddling, and water can flow along the top of the stones, away from the house.
Not much else can be done. Pitch the water away, replace any obviously delaminating pieces. Never seal.
I hope that helps and bid you a merry Christmas!
Hi Devin! This blog post was extremely helpful in warning me of the dangers of sealing flagstone. But I do have a question.
I live in Washington, DC, and I am currently having a new dry-laid flagstone patio installed (variegated Pennsylvania bluestone). I love the look of the flagstone when it’s wet, but it looks faded and too light when dry.
Do you know of any sort of stain I could purchase that would bring out the colors / offer a wet/darker look, without the risk of delamination after a bunch of freeze-thaw cycles? Maybe something that penetrates the stone but doesn’t seal it, so moisture can get through?
Thanks for your help!
Matt
Note: I’m told that a water-based penetrant stain could work. Foundation Armor suggests this one: https://amzn.to/3oTsBHv
It seems like they know what they’re talking about, since on another page (https://www.foundationarmor.com/natural-stone) they say that they don’t recommend sealers for flagstone: “While acrylic sealers have been used after a successful test area, it is important to make sure that natural stone remains breathable.” They recommend the WL550.
In your years of experience, have you ever seen a successful stain to get the flagstone looking darker? Thanks again!
Matt,
Hey, so after reading your first comment, I got in touch with these guys:
https://masonrystaining.com/gallery/natural-stone-gallery/
Their product is a stain, meant for natural stone, and I read somewhere on their website that it is breathable. What I want to know is: has anyone used it to take varigated bluestone and bring out the colors, darken it slightly, give it the wet look?
This is an excellent question you pose by the way. I’m remembering back to a 3,000 square foot patio I built, where the customer insisted on going with the denser iron stone, idk, some type of stone from idaho. Dry. This stone had a deeper color saturation, similar to bluestone when it’s wet. The problem was their idaho stone took twice as much time to cut, was heavier, came in awkward sizes and shapes…..it would have been much much easier to build them their patio, if we had a way to use bluestone, then darken it.
So good question. I’m still waiting to hear back from the stone staining company who I reached out to–will get back to you, after speaking with them.
Thanks Devin! I’m eagerly awaiting their response. From reading various forums it seems like there is a big demand for this sort of product from new flagstone patio owners, and it could also be quite useful for masonry artists like yourself!
Could it also be possible that Pinterest etc. gives many of us amateurs a mistaken impression of what dry flagstone looks like? It seems like a lot of the photos online are high contrast, or taken when the stone is wet.
It reminds me of the years I spent pining for a clear view of the Milky Way. I was basing my understanding of what the Milky Way looks like on the incredible photos I had seen. But when I finally found myself in one of the darkest spot in the world — the Atacama Desert in Chile — I was underwhelmed! Sure, it was beautiful, but it wasn’t like the photos. That’s when I learned that cameras see the world in a different way than human eyes do. The lens keeps gathering photons and layers them on top of each other, making the Milky Way bright and colorful in images — even though the human eye can never perceive it that way.
Obviously it’s not exactly the same, but perhaps it’s worth ruminating on the common experience of misplaced expectations. Perhaps we should learn to love things as they are, and not as we expected them to be.
But I still want my patio to be a *wee bit* more vibrant 🙂
So I spoke with Jennifer at masonrystaining.com
It turns out they do not sell a product, rather they are a nationwide masonry staining contractor. Apparently they have a propriety process inwhich they create a fully breathable stain and they can match any color of stone. She said they can do drastic or subtle color changes, so a slight darkening/enhancing should be possible.
They send out a rep, who works up a sample….then you hire them to stain your project.
They can stain flagstone, but she warned me that they can’t guarantee any flatwork, as foot-traffic, or incident, may marr the staining. As such, they deal more with walls and vertical surfaces. Also, remember that deck staining tends to need to be re-done, every few years….and this company does not sell their stain, they apply it themselves….so probably rather expensive to re-stain your patio every few years.
So that’s one option, expensive and no promises.
The link you provided for foundation armor…..idk, I read both pages and yea, you certainly don’t want to go with anything acryllic or that creates a film.
This line, from their website worries me:
“It penetrates deep into the substrate where it chemically reacts to form a hydrophobic barrier within the pores that reduces surface water absorption by up to 95%. It will darken the surface to slightly enhance any dull and faded coloring.”
Then at the bottom of the page they mention beading may occur.
That has me concerned. If water can’t get in through the top…..then how does water get out? Water beading up sounds like a bad sign.
Well, I may need to edit the article above. For ten years or so, my answer to “should you seal flagstone” was always “no, but if you do, then go with a matte finish. Anything glossy will be slip hazard and may trap in moisture”.
Later, I ammended my answer, when I realized the matte finishes also trap water,
Well, I may just need to amend that to “No, do not seal. But if you do, then make sure the product claims to be breathable, at least, but even then it’s a gamble”.
I have used Aqua Mix stone enhancer on our flagstone patio and walkway. Its expensive but it does the job. Note that we are located in FL so I don’t know how well it would work in northern climates.
There are plenty of reviews on Amazon under the quart size container that they have listed for sale.
I’ll admit, this stuff does look like it *may* do the trick.
a) it claims to be an enhancer first, and sealer second. They’re making that claim in that order, partly to shush up the chorus of experienced masons who are going to sound the alarm whenever anyone suggests sealing grade-level exterior stone. And b) it claims that it “Allows moisture-vapor transmission”.
As a professional, I have my concerns.
And yes, good point–these issues are much more of a concern, in a northern climate.
Hi, Devin. I’ve explored your website with great interest. Wish I was a little closer to Effort, PA so you could apply your artistry to my (fairly ordinary) patio project. I want to have an elevated dry install variegated thermal flagstone patio, because man-made pavers just look blah. At the stone supply company, their display patio of this material looks great, but the pallets of stone look duller on the surface. Does this flagstone kind of smooth out a bit as it ages and with wear?
If the material on the pallets looks more dull than what they have on display, then a) the palletized material may be dusty. The quarry where it comes from, everything is covered in dust. Or, b) it could be a duller colored material. C) maybe the stone supply company used a sealant/stain on their display patio–to help sell them some stone 🙂
Now usually, I recommend homeowners against doing an entire patio in thermal flagstone–especially if it’s all one color. It just tends to look like a manufactured faux stone, if it’s all one colored and with a thermal surface. Varigieted, okay, you won’t have that problem quite so bad, but you won’t miss that natural stone surface texture?
In my experience, some contractors will recommend that you go with thermal flagstone….this is because it’s easier for their workers to install, because it is uniform thickness. That’s a bad sign in my opinion. They may try to install it the same way you install concrete (blah) pavers. Screed out 1″ of sand, and just drop the flagstones on top. Easy! But wrong. Next they sweep poly sand into the (too wide) joints. Easy, but wrong.
Anyway, I hope that helps
Thanks for your reply. I do prefer natural cleft flagstone, but was afraid it would send install costs skyrocketing.
You wouldn’t happen to have any current jobs or consultations scheduled in the farther range of your normal territory in the Main Line, would you? I’d like to arrange for a consultation, but a close to 4 hr round trip just to come here for an hour seems too much. I live near West Chester, PA– about 20 minutes farther south of jobs you’ve had in Chester Springs or Devon.
Thank you. I do prefer the look of natural cleft flagstone, but was concerned it would send the install cost skyrocketing. I would love to arrange a consultation with you, but a nearly four hour round-trip for 1 hour here seems too much to ask. Do you happen to have any current installations or upcoming consults in the southeastern end of your normal range of territory? I live near West Chester, PA, about 20 minutes south of the Chester Springs or Devon areas you’ve cited.
Thanks
I was just in Plymouth Meeting yesterday and will be visiting Roxboro one day next week… visiting chester springs some time soon, too. Price for a site consultation will be the same for you as it would be for someone a mile down the road from me and it won’t be too much of a drive.
Are you wanting my opinion as to how things should be done and design advice so you can DIY, or hire someone else? Or are you looking to possibly hire me?
Either way, email me at devin@devineescapes.com and we’ll see how I can help.
Hi Devin,
We have Tennessee crab stone on our patio for ~12 years now and are really unhappy with the annual appearance of mold/mildew that turns the stones green. We powerwash/bleach it off and use a penetrating sealer (Stonyl) that seems to do nothing to protect the mold so we repeat this time-intensive, futile process every year or so. We believe the stones were set well (with gaps generally less than an inch apart), but the polymeric sand mortar is progressively falling out and weed growth is worsening that. So, we are ready to clean, reseal and “regrout” the whole mess and would appreciate recommendations on what to use to seal the stones and if there is a high quality of polymeric sand that should last at least 5 years or so without allowing weed growth.
We are more interested in a clean look and low maintenance, so are open to using any time of sealant and grout that will achieve that. (Natural look is less important to us.)
Josie & John in New Jersey
You are spending a lot of time and money using two products that I have never recommended. Polymeric sand seems great (sometimes) for the first year. Then it’s a broken up, cracked mess–causing more maintenance, not less. Also, you are spending time applying a sealant….and complaining that it doesn’t work. This next bit shouldn’t come as as surprise: my advice is to stop wasting time and money with these products.
Usually, if a patio is getting a dingy, gray/green mildew/mold/algae sort of problem–it’s usually a damp and/or somewhat shaded part of the yard. Maybe some tree pruning might let some sun unto the patio, let the air flow a bit more, and stop the mildew issue.
But this is entirely an issue of personal preference. Most of my patios get installed as varigated Pennsylvania bluestone, or lilac bluestone, or true blue bluestone. Some of these patios retain there original color over the years. Some of them age and patina. Yes, what you’ve called mildew others have called “patina”. Some of these patios develop moss in the joints–which some people love. Other people fire up the pressure washer once a year or once every other year.
These flagstones in this walkway are not quite exactly the original color that they were when installed. The joints are filling up with moss…might even be a weed in there too! The homeowner likes the moss and feels no need to power wash back to the original color. Their patio and walkway gets full sun for part of the day, but shade for part of the time too–a stand of pine trees on one side, plus the house on the other side combine to keep the air just a bit more humid than other parts of the yard. Moss then fills the joints.
Okay, maybe that doesn’t help you…if you feel that your patio becomes and ugly color every year. But then, would the green tint to the flagstone still be a bother–if the joints were a brighter, moss green? If moss won’t help, then what do we have–a 500 square foot patio or something? Would take me 30 minutes to power wash and another 45 minutes to re-fill the joints with stone dust aka stone screenings.
Hi Devin,
We are in a bit of a quandary. We had a flagstone patio laid over old aggregate. The landscaper who did this got what appeared to be a good result. After grouting he DID not wait 24 hours before sealing with an acrylic sealer. We are now left with a whitish appearance in the grout joints. I think this is likely due to lack of drying from the pressure washer cleanup before sealing. I believe what we have is “bluestone”. Is there anything that can be done at this point?
Thank you,
Steve,
I’m only seeing problems here.
For starters, you mention the flagstone was set on existing aggregate–okay, that’s fine. But then the joints we’re grouted. Sounds bad. You mean the joints we’re mortared, I assume… Problem is you don’t want to use a rigid mortar in the joints, if the foundation is aggregate. The inflexible joints will crack, because the foundation does flex.
Then the patio was sealed…
Which I do not recommend.
Now if the joints are mortared–then are the flagstones laid in a bed of mortar? Or are the set in sand or something?
I have many how-to articles that may be of use here:
https://www.devineescapes.com/ask-devin-building-flagstone-patio-on-gravel/
We have a bluestone patio that was mind in northern Maryland it has been down for 30 years we recently re-pointed all the joints and thermal to the entire patio surface all the natural stone color returned but we would like the wetlook as people refer to it so I found a product called Natural Stone. It is manufactured by a company named alliance which are located in Canada this particular product is designed especially for Blue Stone ceiling it is breathable according to them and it is water-based. Our patio is installed on a pre-poured slab with reinforced rebar. Has anyone had experience with this product they also call their products Gator .
They make many different types of sailors and Polly metric sand but this particular product especially made for bluestone it will give the wet look.
Please advise.
Never used this particular sealant… But then, I never use any sealant for grade-level stone…. Or pretty much any stone, ever.
But I am familiar with this gator company. Their polymeric sand, “gator dust” fails…. every time. As described in this article.
Every landscape supply place carries it…most reputable masonry supply places don’t. Have been seeing the stuff since the early 2000’s….and have never seen it perform well for long.
That’s the company you’re talking about buying from.
The wet look is available for free–every time it rains! Sorry. I did mention another product in the article above, and provided a link. Personally, I wouldn’t use it—but I’d use it before using anything gator makes, that’s for sure.
Good luck on your quest.
HELLO! SORRY I ONLY NOW FOUND YOU. HAD FLAGSTONE PATIO LAYED ON CONCRETE WITH POLYMER IN JOINTS 11 YEARS AGO. THE EDGES WERE NEVER CONCRETED IN SO WE HAD CONSTANT POP UPS WHERE THEY JUST “CUT” EDGE OF PATIO INTO DESIRED SHAPE. NOW, HAD CONTRACTOR REMOVE OLD POLY SAND AND REPOINT WITH MORTAR. THEN HE SEALED IT. OH NO! HE OBVIOUSLY DID NOT CLEAN THE FLAGSTONES. WE HAVE SEALED IN MORTAR HAZE, SPLASHES, AND LITERAL BLOBS OF CONCRETE IN TOP OF THE FLAG STONE. CONTRACTOR SAYS HE WILL REMOVE IT WITH ACID. I NO LONGER HAVE ANY FAITH IN THIS MAN. PLEASE HELP! AFTER HE PUTS DOWN THE LIQUID ACID, WHAT STEPS MUST BE TAKEN TO GET OFF THE CONCRETE? AND IS THE MORTAR NOW COMPROMISED? AND DO I LET HIM RESEAL IT? (AFTER READING YOUR POSTS, I DON’T WANT TO BUT AM WORRIED ABOUT THE CONCRETE’S INTEGRITY AFTER APPLICATION OF ACID.)
If there’s blobs of concrete that need to be removed…then you’d first have to manually remove them by chisel. The best that acid can do is clean up a thin discoloration/stain caused by mortar–but not actually lumps of concrete.
My garage leaks at the floor, but on the other side near the house it’s just damp. I just had a flagstone patio installed. Could the water come from underneath? I notice that there are some cracks from the mortar near the flagstones.
Possibly, water could be coming up from underneath–but there’s too much here that I don’t know. No offense, but your statement “my garage leaks at the floor”–seems like a typo, perhaps? But if the stones are damp, no standing water, well, that might indicate water coming up from below. Also, the flagstone was “just” installed. So recently. And yet, there’s cracks in the mortar, near the flagstone. Cracks, or separation between the mortar and the flagstone are common. That’s where the cracking often starts. Often, this is caused because the mortar used was too wet. Mortar that’s too wet can cause a host of problems….and mortar that is mixed too “lose” (that’s mason talk for too wet) will then form solid, but be more porous than a stiffer mix. This is because that space that was taken up by water, in the lose/soupy mortar, is now just air, tiny empty pockets of space, within the mortar. As such, the mortar may take up and absorb more water and faster, as compared to a better mix.
All of the above is hypothetical–as I know very little about the installation, or about your site conditions. But soupy mortar will be weaker, and more porous. And if the cracking is showing up less than a year after the installation, then that supports my hypothesis. However, even if the mortar wasn’t 100 percent the best…and even if the concrete foundation (which I assume exists beneath the flagstone and mortar) even if the foundation was mixed too wet too, then you usually wouldn’t have stones absorbing so much water from below that they show up damp on the the surface. As such, I’m wondering what’s going on with the grading around the house and garage, and I’m wondering about downspouts, because there’s likely a second contributing cause to this situation.
If the flagstone is on a deck, should it still not be sealed?
I wouldn’t. The big question is why? I’ve never seen a convincing reason to seal flagstone. Flagstone on a deck….can still absorb water from below. Just like grade level flagstone. And just like grade-level flagstone–it wants to let that water out from the top. But you sealed the top. Again–why? Do you think the stone will last longer if coated in acrylic? We’ve never once seen evidence of this being true.