59 Comments

1. 

   Stephen Thorntun on July 21, 2015 at 8:09 pm

   This is a good service you provide. Thank you!

   Reply
2. 

   Jeff Hamilton on July 31, 2015 at 2:00 pm

   Thank you for having this service! We were impressed and grateful for your already helpful blog posts, but then my wife noticed you also offer phone consultations and we knew we had to talk to you. Your advice has proved most helpful, and we now have a flagstone patio with stable joints and no more drainage problem. Thanks Devin!

   Reply
3. 

   Jeff Smith on August 10, 2015 at 1:32 pm

   Thanks so much for the phone consultation. To be able to have a conversation and ask specific questions regarding hardscape installation is a very helpful service you provide. Your pro-guidance is much appreciated.

   Reply
   • 

     Devin on August 10, 2015 at 1:48 pm

     You’re welcome Jeff, and thanks for leaving feedback. Good luck with the patio!

     Reply
4. 

   Victor on August 19, 2015 at 11:44 am

   Devin – thanks for your advice a while back. With the info you provided I was able to have a much more informed discussion with my contractor, and he found a different local mason to do the work. I’ve had discussions with him and he seems to plan on doing the work exactly like you described it. My only concern is that he plans on doing all the work – hearth included in one day. Does that seem feasible?

   Thanks again,
   Victor

   PS – I will probably reach out to you for more consulting work next year when I tackle the beat up stone patio/porch on the house.

   Reply
   • 

     Devin on August 19, 2015 at 11:59 am

     Feasible, sure. It really depends on the masons technique and level of attention to detail. If I had my pieces pre-cut, or if my helper was on-point, then I could do it in a day. I would want the client to be ready for me being there longer though–so when you and I were talking about the possibility of me traveling to New York to do the job, I may have suggested a longer time frame. That’s part of the under-promise over-deliver thing. I’d rather get done earlier than I say, rather than later, and try to be ready for delaying surprises.

     I look forward to hearing from you about the stone patio then.

     Reply
     • 

       Devin on April 20, 2016 at 1:00 am

       Follow up:

       This local mason built a fireplace that was not quite what the homeowner was after and so I ended up re-buiilding it myself.

       Victor can tell us that story:

       https://www.devineescapes.com/testimonials/testimonialsvictor-in-irvington-ny

       Reply
5. 

   Brian Hoffstead on October 24, 2016 at 12:59 am

   I think it’s awesome that you offer so much free advice on your how-to blog posts. I have found your flagstone articles very helpful, but I have some specific questions and would appreciate your expert guidance just to help clarify on some fine points and make sure that I understand the whole process from start to finish. I’ll be emailing you soon, to set up a consultation!

   Reply
6. 

   Darren on September 3, 2017 at 11:34 pm

   Your work is amazing. Do you ever do projects in the Washington area?

   Reply
   • 

     Devin on September 4, 2017 at 12:46 pm

     Yes, sometimes my work has me travel, to Long Island, Delaware, and other nearby states, but I will travel further, if a project is interesting to me. My next sculptural commission is actually just outside of Washington (DC) in the Silver Springs area and there’s talk of me doing a job in Oregon next year.

     Reply
7. 

   Erin Cassady on July 27, 2020 at 12:22 am

   Hello. I had a “professional” install my 20′ X 20′ flagstone patio. He works for a contractor, but is not licensed himself. I’m not happy at all with the work. He is telling me that cracks in the mortar are “normal” and that is “the nature of concrete,” to which I replied, “maybe over time, but I don’t think it’s supposed to begin that way.”
   It was 80-85 degrees outside during the install over many days, as he would do a small patch in the afternoons or evenings after his regular job. He did not attempt to keep it moist over those days, no tarps, no misting. The spaces between the pieces is also larger than I expected. I would love to send you a picture so I can hear from a professional whether I should pay for this work. I don’t know whether it is fixable or if I should invest in a different contractor to redo it. Can I send a pic? Will that cost $60?

   Reply
   • 

     Devin on July 27, 2020 at 1:55 am

     Hello,

     Yes, I can look at photos, and offer opinion as to what went wrong and how/if it can be fixed. Send 60$ via zelle, or PayPal, and email photos and let’s set up a time to talk devin@devineescapes.com

     Reply
8. 

   Annie on September 9, 2020 at 5:37 pm

   Devin: You have been a godsend! You don’t know this, but I came across your blog in mid July when my long awaited patio project finally got started and then went so wrong by the 2nd day. I did a Google search to find out more about polymeric sand. Then I asked for info on the difference between poly dust and poly sand. THAT is when I came across: “What to put between flagstone joints-polymeric or ….” and I followed this link to devineescapes.com. I was so surprised at what I found.
   It was way more than some simple answer to what I had searched. I knew a little about DG, and first off, it went into “stone dust” and “screenings”, of which I knew nothing. Further, you gave me in depth knowledge about polymeric sand that I had not anticipated. And I knew it was the truth because I had bought a bag and experimented by filling the cracks that had developed, over the thirty-two years, separating the pool deck from the bullnose 1/8” to more than ½”. I learned so much more about DG than I had even given considered—like the “screenings”, the powder, the size of the crushed stone.

   Following this article came the comments section. OMG! That alone was worth a consultation fee. I read for two days! I read some a second time. AND I looked for dates, hoping to find this to be an active site, since the comments started in 2014. Can’t tell you how happy I was to see the last posted comment was on July 7, 2020. AND, you, in fact, responded to the person!
   In the days ahead, I found so much more authored by you—I was sure I was going to be billed (joking). I had also come across two other sites the same day I found yours, but they barely covered my search question and did not offer the IN DEPTH knowledge that yours so generously shared. After completing reading and rereading everything on that page, four days later, when it was too hot to work outside, I clicked on “archives” and the flood gates of information opened. I kept some of these open in my browser for weeks and referred to them daily. I hope you get paid for these articles!!!!

   So, now we’re into Sept. I no longer have a contractor, by mutual decision. You have guided me through SO much and you don’t even know it. You have been a godsend! Thus, that’s why I’m writing this today. Plus, for some unknown cause, I arose from a seated position three days ago and rolled my ankle badly. On the holiday weekend! Heeling now. But Devin, I want to thank you, so much, for all the help you have given me already. You even responded to one of my comments to one of the comments I had read on your site—somewhere. I’m actually trying to organize myself to have some meaningful questions to put to you. I am struggling with the slope and drain issues of my patio—complicated because of the level of my pre-existing rain gutter drain that I really do not want to disturb.
   You have answered in your articles, and comment sections, pretty much anything I might have asked two months ago. I still cannot believe how much help your site has been to me. Oh, did I mention I am a bit of a DIYer. But never thought I would attempt laying this flagstone! You have given me so much information, I have commenced installing a portion of the flagstone on my patio area. But I need to get back to leveling and sloping the entire area and deciding on whether I will be able to have a drain and where. So, I will be contacting you to set up a consultation. But you have helped me immensely already. I’m sure I am speaking for so many others when I say this. But like you, I do like to write too. See, I did read everything! Sorry this is so long! I just hope it conveys how grateful I am to have found you. Most sincerely, Annie A

   Reply
   • 

     Devin on September 11, 2020 at 2:08 am

     Annie,

     I am so glad you have found my articles useful. I appreciate it when my efforts are appreciated 🙂

     Thank you so much for posting this thoughtful comment. I’ve never gotten paid for these how-to type articles, not directly anyway. But the articles help people to find me, establish credibility and trust with prospective clients, and also lead to the phone/email/skype consultations for which I do accept compensation.

     Please rest that ankle while you’re gathering your questions. When you’re ready to get back to work to complete your patio, I’ll be happy to help!

     Reply
9. 

   Mike on September 14, 2020 at 2:43 pm

   Hi Devin,
   Great info here thanks! Question regarding the slope for drainage.
   My patio will be rectangular 112″ x 256″. The 256″ dimension is along
   the house so I’m assuming I’d want the slope based on the 112″
   dimension to drain water away from the house. I live in central NY so
   you recommend a 6″ base for cold winter climates. If I start with a 6″
   base and use 1″ slope per 4′ I end up with 3.7″ of base at the
   opposite side of the 6″. Obviously If I want to have a minimum 6″
   base I’d have to start with an 8.3″ base against the house.
   Obviously I could save some time and money if I went with the 6″ to
   3.7″ slope but I’m not sure of the implications of skimping on the
   base in this cold climate zone. I’d try to achieve all numbers after
   compaction of course. FYI the driveway mix I’m thinking of buying is a
   crushed limestone ~3/4″ to fine. Any advice would be appreciated.
   Thanks,
   Mike

   Reply
   • 

     Devin on September 14, 2020 at 9:37 pm

     Yes, you want the slope going away from the house.

     In your case I would either a) go with 8.3″ on the uphill side and 6″ on the downhill side or b) excavate a bit of soil on the downhill side so that you can end up with 6″ gravel for the entire patio. Option b is recommended….but either way would probably work, just option b will maybe shed water a bit faster, since the flagstone is pitched, but so is the soil.

     Crushed stone 3/4″ to fine is good.

     The 1″ slope per 4′ is a guideline. Anywhere from 2″ to 3″ will work fine–will not fill too steep, but will still shed water. The 6″ of gravel is a guideline number too, not a hard and fast rule….so you could even go 7″ on the high side, 5″ on the downhill side, leaving you with an acceptable 2″ of fall and an acceptable 5 to 7″ of gravel. As a professional, to play it say and make sure I’m giving my customer the best possible product–I’d most likely dig out the soil, so that the soil grade is also pitched, and I’d lay 6″+ of gravel.

     Best of luck and if you feel you need further guidance I’m always available for phone consultations and there’s many more posts in the how-to section of my blog.

     Reply
10. 

    Joe on December 14, 2020 at 3:24 am

    I am very grateful for the two consultations that Devin provided. We had the first one before I started work During that call, I confirmed how much I had to dig, what type of material and tools to purchase, and how to set the grade for the patio. I also got a sense of how a professional like Devin approaches his work–stone by stone and as an artist who takes pride in his work.

    When I was about half way through the project, I called Devin again to go over some questions I had about fitting the rocks together and how to best level the rocks, especially ones that have very irregular bottoms. After that call, I went back and tightened up some of the gaps and continued to take my time finding the optimal spot for each stone. Larger pieces were placed along the perimeter and I worked my way into the middle stone-by-stone. It took me about two months to finish the project since I was working on weekends and whenever I could grab an hour away from my desk job or other responsibilities.

    With two hours of phone consultations, I gained the knowledge and confidence necessary to complete the project. Taking into the account the thousands of dollars I saved by doing the labor myself, I think it was very reasonable to pay for Devin’s expert advice. I’ll send Devin some photos of my project so he can post them if he wants.

    Reply
    • 

      Devin on December 16, 2020 at 3:07 pm

      Thank you for your comment Joe, I’m very glad I could help you! And I will certainly post your photos–they look amazing, truly impressive that a DIY home-owner built it.

      Reply
11. 

    Merril on April 12, 2021 at 8:16 pm

    How thick do dry laid flagstones need to be? We have a friend who had their slate patio removed. We think they are bluestone, but so far no one is sure. It was laid in cement, and the slates range in thickness from 3/4″ thick to around an inch and a quarter thick. Assuming we set the cement-stained sides downwards, will we be able to use these for our new walkway?

    Anyway, their patio was around 400 square feet so even though some of the pieces broke during demolition, I think we still have enough to create our stone walkway which will be less than 50′ long, and probably only 3 or 3 and a half feet wide. The pieces are all squares and rectangles, ranging in size from 1 foot by 1 foot, to 2 feet by 2 and a half feet.

    Thanks!

    Merril

    Reply
    • 

      Devin on April 12, 2021 at 11:04 pm

      Great question. The general rule is that you want dry laid flagstones to be around an inch and a half thick. Much thinner than that and you end up with stones that may shift underfoot. Thinner than 1″ thick, and they become likely to break. Having said that, a flagstone that is 2′ x 2′ or bigger, is going to have enough surface area that it will stay steady underfoot, even if it’s only an inch and a quarter thick, or even slightly less. Meanwhile, a stone that is only 12″ x 12″ in surface area….that stone is going to be hard to get stable, even at an inch and five eighths thick. Anything under a square foot in surface area–I want to be at least 2″ thick. On some of my patios and walkways, you can see smaller pieces–like even a 6″ x 6″ triangle piece.

      

      That 6″ triangle in that walkway is 3.5″ thick. It’s more of a cobble stone, than a flagstone. A flagstone is a slab–big surface area, fairly thin. A cobble is proportioned more like a brick, or a belgium block–almost as thick as it is long/wide.

      So from what I’m reading about the stones you have available…the smaller pieces you have will not be useble on your project. You could use them if you insisted….but you may be disappointed with the results, especially in the long run. The larger pieces that you have may mostly all be usable….I’d just get rid of the thinner ones of the bunch. Don’t throw them away of course! They may be useful in a garden wall or something, down the road.

      I could have answered this question more simply: use a dead-blow type mallet to set each stone into place. If the stone cracks–it was too thin!

      Reply
12. 

    Matt on May 19, 2021 at 9:37 pm

    Thanks Devin so far with my consultation and the advice on the Blog. I couldn’t do this project without all of this valuable information. I have a few more questions. First, some say to lay edging on the border of a Flagstone patio build. Do you recommend any type of edging? Also, do you use a hand tamper or a plate compactor on the base? My project is a 13 x 11 patio, what would you use to compact for a project that size?

    Reply
    • 

      Devin on May 19, 2021 at 10:10 pm

      No edging. A contractor using edging for natural flagstone…. Is a paver contractor (not a stone guy). Stone guys know:

      https://www.devineescapes.com/ask-devin-plastic-edging-for-flagstone/

      A vibrating plate compactor will save you some time… But at less than 150 square feet–it’s not too big to be hand tamped. Hand tamper works just fine… In 2009 I built a dry laid stone patio, 500 square feet–and hand tamped the whole thing. Patio still looks great and has never required any maintenance accept for sweeping dust into the joints and pouring boiling water on any weeds every once in a while.

      Reply
    • 

      Bob Tartaglia on June 26, 2021 at 1:20 pm

      I just applied the final screening sand layer in between the flagstone and lightly wet it down do I still need to protect it from the rain with a covering of tarp, if so for how long?

      Reply
      • 

        Devin on June 26, 2021 at 2:16 pm

        By “screening sand” I hope you mean stone screenings–crushed stone/stone dust, not sand?

        Sweep stone dust into the joints and then hose down, with your hose on shower setting. Then top off joints again and hose down again. Sweep off excess from the tops of your stones and hose down again.

        No need to tarp. Rain will be helpful, if anything. You want the stone dust to settle down in there. If there’s any voids underneath your flagstone, the joint material may settle down in there and fill them.

        More info:
        https://www.devineescapes.com/taking-care-of-your-patio/

        https://www.devineescapes.com/leveling-dry-laid-flagstones-how-to/

        Reply
        • 

          Bob Tartaglia on June 26, 2021 at 9:22 pm

          Thanks very much! Not sand. Specific “screening sand” (crushed stone).

          Reply
          • 

            Devin on June 26, 2021 at 10:20 pm

            You’re welcome, I’m happy to help 🙂

            Reply
13. 

    Matt on May 24, 2021 at 9:05 pm

    Devin, Matt here again. I’m going to begin my project tomorrow. One thing that is not clear to me is that after I lay the stone out in the pattern I want, and then I go begin to level, and add Stone Dust (amount depending upon the thickness of the stone), do I wet the stone dust at all before placing the stone back on, or do I keep the stone dust dry? I know I wet the stone dust when filling in the joints at the end, but what about during the leveling process?

    Reply
    • 

      Devin on May 24, 2021 at 9:28 pm

      Good question. I usually go dry, but actually you can use wet stone dust as a leveling agent. I’ve done this, once or twice when I was laying really thick flagstones and didn’t want to lift them out again during the leveling process. So what I did is filled a bunch of 5 gallon buckets with stone dust, then added enough water to thoroughly soak the stone dust. Then you dump stone dust down, smooth it out by hand or by trow, being sure to use at least enough, perhaps just a bit more material than you think you’ll need. Now, when you put the flagstone down, you can persuade that stone down to its proper height, using the mallet.

      Using the above system…is supposed to be similar to laying flagstones in mortar. You’re setting the stone down on a semi fluid/semi plastic medium. Now I usually go dry and haven’t done the wet method often enough to say this for certain….but it probably makes getting the flagstones wobble-free a bit easier. You smack that flagstone with the mallet, it’s going to cause the wet stone dust beneath it to move into and fill any voids. Theoretically, at least. And since the stone dust is wet, if you have too much stone dust down there and you pound it with the mallet–the flagstone should sink down, a bit easier, as compared to dry stone dust, which will only allow you to sink that flagstone a little bit, maybe an 1/8″ of an inch. With wet stone dust–it might be more like a 1/4″ of sinking possible.

      So the wet stone dust method sounds easier–how come I don’t do this very often at all? Because a) it’s a dirty mess. The dry method, I’ll be dusty. The wet method will leave both hands blackened up to the elbow. And b) the dry method works just fine for me. But every once in a while, like once every couple years, I’ll be having some frustration in getting them stones level–and will resort to the wet method. It really is so rare that I do this, that it’s hard for me to say how much easier the method is–but both methods leave me with the same end result.

      Reply
14. 

    Matt on May 26, 2021 at 2:06 pm

    I ended up being short about 1/2 inch to 3/4 inch paver base. However, I have extra sceenings/stone dust that could cover the difference, but that would mean 1.5 to 1.75 inch of screenings. Good idea or bad idea? I don’t want to have any future problems.

    Reply
    • 

      Devin on May 26, 2021 at 2:16 pm

      First of all–big thank you for leaving the 5 star review on google!

      Stone dust and road base (paver base) gravel are somewhat interchangeable. In the situation you describe, you could mix the screenings into the gravel a bit–the gravel already contains 1/4″ chips and fines–and you can increase the ratio of smaller bits to larger sized gravel quite significantly without having any problems.

      If the gravel is already down, you won’t need to perfectly mix the screenings in either…..I’d add the 3/4″ screenings, then shovel up some of the gravel….rake it all together. When you’re finished, the top inch or so of your gravel base may be about 50% screenings–and that’ll be okay. Hose down and tamp, then level each flagstone individually in an inch or so of stone dust.

      Reply
15. 

    Matt on June 11, 2021 at 9:32 am

    I’ve happened to be lucky to just acquire a few hundred square feet of square cut sandstone. I’m planning out an area in my yard to use these. While saw cut, they have been nicked up to look natural. Still, they can be laid in a way to where there would be little if any gap (probably an 1/8 to 1/4 inch gap). Is this a good idea or should the gap be purposely made larger for any reason (like for future leveling, etc.) Is there a minimum recommended gap size, in your opinion?

    I found a picture of what I’d be able to do. see this link below.

    https://selectstonesupply.com/uploads/products/squarecut/ebel_black_square_cut_flagstone_patio_3.jpg

    I wouldn’t mind having the gaps like this (thin), but with that being said, how do you lift stone out, that is so close together, without buying a grabbo (as you have detailed in other posts), or would that be a must in a situation like this? Any advice you could provide would be appreciated. all of your suggestions have been spot on so far! Thanks again for your consulting services…well worth it!

    Reply
    • 

      Devin on June 11, 2021 at 12:54 pm

      The photo you’re showing me looks good. Tighter joints mean less joint material washes away or gets kicked out of place, but yes, in my opinion there is such thing as too tight of a joint. I prefer to keep joints at least a quarter inch wide. If you make your joints 1/8″ or even tighter, then minor inconsistencies between different flagstone’s elevations will stand out more. Say on stone is a quarter higher than one right next to it. If there’s a gap between the two stones, you may never notice that minor difference in height. But now if the two stones are touching—you’re going to notice it.

      Then again, in 2019 I spoke with a customer from 2009–the tightest jointed irregular flagstone job I’ve ever done. My customer said the patio is holding up perfectly and he never felt any need to have any stone re-leveled.

      SO I’d go with 1/4″ to 3/8″….or 3/8″ to 1/2″, or something like that. To lift stones out of place, I use the blade end of a brick hammer–and yes, this is another reason to not have too tight of joints. Smaller than 3/8″, you end up having trouble using just the brick hammer to pry stones out, and may have to use a flat head screw driver as well. Grabo is nice, and saves you a few seconds of prying….but then, your brick hammer will do just fine–especially if your joints are a solid half inch or more. Smaller than that–you’ll either want the grabo, or will be using the flat head screwdriver to pry the flagstone up just a little–and then using the brick hammer to get it a bit more up–and the grabbing the stone with your fingers and prying it out all the way.

      I’d go with 3/8″ to half inch, myself, which are the size of joints used in this job:

      https://www.devineescapes.com/wp-content/uploads/2020/05/stone-patio-scaled.jpg

      This next one was done with the help of the grabo….has joints that are 1/4″ to 3/8″ so just a bit tighter:

      https://www.devineescapes.com/wp-content/uploads/2021/06/dimensional-flagstone-with-tight-joints-1200×1004.jpg

      Reply
16. 

    Csaba Paltan on September 20, 2021 at 11:07 am

    Hi Devin,
    I know you recommend 2″ thick for the dry installation but since there is not enough material of the 2″ thick flagstone and they can’t even tell me when they get more of it,so let’s say that
    if I still decide to go with the Quartzsite,(because I LOVE that color) would you be completely against going with the 1-1.5″ Quartzsite?
    Do you think that it would break easier because of the harsh Chicago winters or more like if heavier equipment would go over it or in case it wouldn’t be properly installed ???
    If quartz is so hard to cut I am thinking that it would not break so easily???
    What do you think?
    I really have to make a decision and order some stones in about a week.
    Thank you so much for your time.
    Csaba

    Reply
    • 

      Devin on September 20, 2021 at 11:42 am

      1.5″ is a good thickness for flagstone. A less than one square foot piece of flagstone should be thicker, like 2″ or more, but larger sized pieces can be 1.5″ thick. It’s all about stability underfoot. A piece that’s 2′ x 3′ will be stable at only 1.25″ thick …a piece that’s only 8″ x 10″ meanwhile will need to be thicker than 2″, just to be stable.

      Reply
17. 

    David on April 27, 2022 at 2:14 pm

    I spoke to you a month or so ago about sealing our flagstone patio. Have a new problem. For weeks have been cleaning off bird droppings
    with dilute tide detergent and water with a nylon brush with no problem. Was away for several days and had a lot of droppings. Cleaned as usual but this time it appears that white spot is left on stones. Need advise on how to resolve.

    Reply
    • 

      Devin on April 27, 2022 at 4:29 pm

      David, if the nylon brush and detergent isn’t doing it, then I’d go with a pressure washer. If small bits of stone are flaking off, then just back off a little bit, hold the wand/nozzle a bit further back from the stones.

      Reply
18. 

    Lisa Faiella on May 2, 2022 at 6:06 am

    Greetings, Devin, from Southern California! So grateful to have
    found your website and blog…and for your willingness to share your
    wisdom. We are laying a tumbled flagstone path, at the narrow side of our house. The stones range from 2 to 3+ inches in thickness. The largest stones are about 15 inches across. The approximate width of the path is 36 inches. It is flanked by two plant beds. Our landscaper is planning on using sand for a foundation, on top of our natural
    soil (which is a clay loam and pretty firm except when we get rain a
    few months in winter).

    We are using soil in between the stone spaces for “Baby’s Tears” ground cover, in the shady area and “Elfin Thyme” at the hot, sunny end.

    Our challenge is to make sure that the stones are stable and level because it will get sufficient traffic and utility use.

    After reading your blog about the cons about sand, I’m concerned about
    possible ant problems, stability and movement of the stones.

    Is sand the best option in our case or is there anything else that can be used that would allow groundcover to grow in between the spaces?

    Thanks a million for any tip.

    Reply
    • 

      Devin on May 2, 2022 at 1:33 pm

      Lisa,

      I would use road base gravel as my foundation and then use stone dust aka crusher fines as my leveling agent.

      1. You dig down about 7 inches, then tamp.
      2. Add about 4″ of road base gravel, tamp.
      3. Lay out the flagstones.
      4. Level up each stone, using stone dust.

      In places that have cold winters, I’ll do at least 6 inches of road base gravel. In California, I’ve done 4 inches….and I know of guys who do only 3 inches.m But soil will shift and settle, even in warm places, so I would do some foundation.

      Stone dust is crushed stone, just like your road base gravel, with fines, only it’s sized quarter inch minus, whereas road base gravel is sized three quarter inch minus.

      In California stone dust will be sold as crusher fines, and as decomposed granite.

      Reply
19. 

    Sal Panetta on May 5, 2022 at 2:18 pm

    Devin
    Hope all is well
    Im repointing a bluestone patio
    What type of mortar would you use to get close to this color joint, its more closer to a white
    I used a lehigh type s
    but its drying more grayish
    Thanks

    Reply
    • 

      Devin on May 5, 2022 at 2:39 pm

      Sal,

      Did you add 3 parts sand…..or are you just mixing up straight portland cement? If the bag says “cement” then it means you need to add sand. If the bag says “premix” or “mason’s mix”, then it already has sand.

      I suspect the white mortar joints you are trying to match might be so white because they mixed their mortar too wet. The wetter you mix it, the lighter it ends up being. But too wet a mix results in a weaker mortar. I’m also suspecting that maybe you tried mixing up straight cement, and need to add sand. Adding white sand to your gray cement might be enough to get you there, otherwise there is the white portland cement option.

      This, needs sand added:

      https://www.lowes.com/pd/75-lb-S-Cement/1000350121?cm_mmc=shp-_-c-_-prd-_-bdm-_-ggl-_-LIA_BDM_210_Concrete-Block-_-1000350121-_-local-_-0-_-0&ds_rl=1286981&gclsrc=ds

      This however is good to go, just add water:

      https://www.homedepot.com/p/Quikrete-80-lb-Type-S-Mason-Mix-113680/100318510

      Mix a small amount and spread it out on a piece of cardboard and set it out in the sun or hit it with a blow dryer–you should have an idea of what the final dried color will be, within an hour.

      This one here, is the white portland cement:

      https://bellstone.rocks/products/lehigh-white-type-s-lehigh?variant=31545217974354

      If you’re buying portland cement and sand, rather than just using premix, then the formula is 1 part portland cement, 3 parts sand, 1/2 part lime. Since you’re trying to match a particular color, you may have to cook up a few batches, let them dry and experiment a bit.

      Premix will be a bit easier, and it works well for pointing flagstone.

      Reply
20. 

    Brooke on August 7, 2022 at 5:09 pm

    Hi Devin,
    I have two more questions for you, now that I’ve had more time to think about the rebuild and demo some more!

    I would like to wet-lay the bluestone (approx 1.5″ thick), and have uncovered the old concrete base. I believe I should use type-S mortar as the first layer after the bluestone — should that be 1″ thick or can it be/should it be thicker? And then what should I put between the old concrete and the type-S mortar that the bluestone is laid in — 3/4 rock, sand, concrete? I’ll have 3.5″-4.5” to fill in (due to the slope/grade as the walkway travels towards the driveway).

    Thank you!

    Reply
    • 

      Devin on August 7, 2022 at 5:21 pm

      Always stick with like–repair dry laid applications with gravel and stone dust. Repair wet laid applications with concrete/mortar.

      Try to keep your mortar around an inch or so thick:

      –less than 1/2″, you risk poor adhesion
      –more than 2″ and you lose strength. Mortar is not structural, in itself–it fills space between masonry units.
      –if wet laying on the old concrete but there is a four inch gap, then you should pour new concrete on top of the old. Let that set up 2 or 3 days before laying the flagstone in mortar.

      Reply
21. 

    KD on December 6, 2022 at 5:17 pm

    Hi Devin,
    Planning to install a flagstone patio for my backyard and just had a few questions. I have found your blog IMMENSELY helpful in doing this as a DIYer.

    1. Any advice on grading when your backyard is naturally sloped towards your house? My particular backyard is about 15 feet till the back retaining wall and about 40 feet wide but have a sloped side yard on one side and a drainage grate on the other. Would you try and redirect the water down but to the side? Live in southern California so rain isn’t a huge issue but definitely still something I want to get right. 

    2. When you are levelling your flagstone placement onto your DG, are you aiming for a slight angle on the level to maintain grade? If so, how do you know if it’s installed correctly? Mostly based on if there is any wobble?

    3. When you order flagstone, do you prefer to order large slabs and break them up and fit them back together or short pieces. Would you break up the large flagstone with a sledge hammer whilst it’s leaning at an angle on something else? 

    Thank you!

    Reply
    • 

      Devin on December 6, 2022 at 6:26 pm

      KD,

      1. Usually, I’d fix this situation with a wall. A) a sitting wall, higher than the patio, on the one side of the patio or B) Possibly build a raised patio, having a wall beneath the patio, allowing you to raise the elevation. (or we could also do C, making the patio a raised patio, and also having a sitting wall, on that side of the patio). In either case, the patio is pitched away from the house, and the yard is pitched towards the side yard.

      2. I set my gravel foundation at 1″ of fall for 4′ of span (this = 2.5″ of fall over 10′, and it also equals 1/4″, over 1′. Stay somewhat close to this level of pitch, and your work will feel level, yet will shed water.)

      I check this pitch using a string line, line level and concrete stakes.

      Then, when leveling out the flagstones, I’m checking with a 4′ level, looking to see about half a bubble/quarter bubble, on that level. Also checking on wobble.

      3. I prefer to use the largest pieces that I can. This does make life more difficult, as you end up needing to lift the stone, make it fit with another stone, cut it, lift it again, try to level it, re-lift it again–and it’s harder, with a heavier stone.

      But when I need to chop up a large flagstone into more use-able pieces, I do this:

      Take a 5′ x 6′ stone, lay it on the ground, flat. No leaning is needed. Then take a stone splitting hammer and intentionally break that large stone into useful shapes. Useful shapes including: house shape/pentagon, Triangle, and bell shape (tapered square/rectangle)

      A sledge hammer may be used to do this sort of break–but not leaning, but flat on the ground. And using the edge of the hammer head, the side, like as if it were a chisel blade shaped head. And not with a random strike–take a soap stone and mark the flagstone where you want it to break–into house/bell/triangle–and then strike, using your rock hammer or sledge hammer, where you drew the line. I tap a few times, along the line–scoring it, dotting it–telling the stone where to break–then I give it a somewhat harder smack–telling it to break.

      I hope this helps!

      And I’m happy to offer free advice, but this time, I want to ask a small favor of you, also. I’ve got some 2023 Stone Art Calendars to sell. Can you leave a comment on my calendar post? This will make it easier for people looking for art calendars to find me.

      Thank you,

      Devin

      Reply
      • 

        KD on December 8, 2022 at 3:57 pm

        Thank you for the wonderful reply. These suggestions are extremely helpful.

        I also have one additional question. If you wanted to make a step leading into a flagstone patio, how would you go about doing that? How would you support the step and raise it higher?

        Reply
        • 

          Devin on December 8, 2022 at 4:10 pm

          Are we stepping down to the patio–from inside the house/stepping up to the house, from the patio? Or stepping up to the patio, from a yard or path?

          And this will be only a single step?

          Reply
          • 

            KD on December 10, 2022 at 10:39 am

            This would be a step down from the house patio door. The ground is lower than the door entrance. Just a single step.

            Reply
            • 

              Devin on December 10, 2022 at 11:31 am

              For single step I’d prefer to use a single stone. A 4 to7 inch thick blocky stone.

              Thicker stone can be used–and partially buried. Bottom of the stone needn’t be flat, can just be buried.

              If no stones thick enough exist, then there’s the option of doing a riser and tread–in this case, only one of each. So it’s like building a really short dry stone wall, and capping it with one flagstone. The flagstone should be large and thick enough so as to be stable under foot.

              This second option is much more complicated.

              Reply
22. 

    KD on December 27, 2022 at 12:39 pm

    Do you recommend DG with chemical stabilizer in it for flagstone patios?

    Reply
    • 

      Devin on December 27, 2022 at 12:43 pm

      No. DG does not need any chemical stabilizer. I’ve addressed this issue, in this article. My recommendation: just use DG or pathway fines/rock dust/1/4″ minus.

      Reply
23. 

    Kathy on July 1, 2023 at 3:44 pm

    Hi,
    >
    > I’m getting ready to hire a landscape company to do my front yard.
    > I’ve chosen.flagstone to build a small courtyard in front with a
    > retaining wall. And the rest will be a mix of steppingstones and
    > ground cover and various flowers. One company uses mortar in between
    > the flagstone and another uses the polysand. Which do you think is
    > better to avoid weeds and that lasts longer without cracking or
    > having problems down the line?

    Reply
    • 

      Devin on July 1, 2023 at 7:54 pm

      None of the above. Mortar is correct, for in between flagstones–but only if the stones are to be set on a concrete foundation. If you’re building on a gravel foundation, then it makes zero sense to use a rigid joint material.

      Same goes for polymeric sand. Back in the 90’s I worked for guys who would use mortar for dry laid patios. The mortar stays put–for a couple years. You get very little weeds, for the first couple years. In the early 2000’s they started coming out with this polymeric sand.

      Polymeric sand, like mortar–stays put. for a while. But the dry laid foundation is moveable. The stuff underneath the flagstones may settle, just slightly. But the joint material, being bound together, with plastic (or cement) the joint stays put. Since the material beneath the joint has settled, but the joint is still in place–what we now have is a void. Soon, the joint will crack up.

      Reasons why poly sand and mortar are popular:

      a) no weeds. For awhile.
      b) the joint is solid….so you can get away with not fitting your stones properly. The large joints form hard, like stone–so a 4 inch or 6 inch joint is no problem, For awhile.

      My recommendation is to fit your stones together properly. Use stone dust as the joint material. In California, it’s sold as “pathway fines”. If the joints are tight then there’s not too many weeds and weeds that you do get, are easily handled with a bit of boiling water.

      Reply
24. 

    Javon on August 11, 2023 at 4:57 pm

    Hi Devin,
    I am loving the info on your website. I’m hoping to do a flagstone patio myself and with the help of some friends. I have a backyard mulched area and a few years ago I laid TrueGrid in the main areas to keep it level and help drain the storm water. I was wondering what your thoughts/advice are for laying flagstone over the TrueGrid, using it as the base.

    I also thought about using flagstone from a local limestone quarry because of price and since I’m in Indiana. But then on one of your comments you mentioned you rarely use limestone, so I wondered about the reasoning there.

    I do get a lot of water from neighboring properties and the TrueGrid has been helpful at helping slow the water and drain naturally. So my hope is to lay a fines/stone dust layer a few inches thick under the TrueGrid and over it before laying the flagstone.

    Thanks!

    Reply
    • 

      Devin on August 11, 2023 at 7:09 pm

      So you want to build on top of truegrid that you’ve already set in place–in a previously mulched area.

      I would not build on top of this truegrid. The first problem is that unless you dug out all of the mulch and all of the top soil….then your truegrid is sitting on top of soil that was previously a mulch bed. So rich, dark, loamy, light soil. No?

      In any case, I dig down to clay, or sand, or some sort of mineral material, before I lay my foundation.

      Also, I never liked truegrid. I’ve used a similar product–ages ago, back when I had to take on some sub contracting gigs. back when I didn’t have full authority and autonomy to build how I choose. Anyway, they used these honeycomb-like plastic cells. This was a new product back then. It was claimed that this 2″ plastic grid, filled with clean gravel(no fines), would serve to replace 6″ of compacted road base gravel with fines.

      So, on this job, we then spread on top of these cells, this pea gravel mixed with this stupid clear glue, that turned the gravel into something midway between being black top–and a rice crispy square. I’m not a fan.

      Anyway, this terrible, foolish, ugly product–cracked up by the next Spring. And a public arboretum nearby used the same product–and it cracked all up.

      And those plastic cells were the hot new product–back in 2008. But they never caught on. I see them once every few years. I travel a lot visiting masonry and hardscape supply places across the country–and these cells completely disappeared for 15 years. Only recently have I begun to see them again.

      My prediction: they’ll once again gain a bad reputation, then disappear. Circa 2040 they’ll come back again!

      So your idea is fines beneath and above the truegrid. Does that mean water just sits, within the true grid? Like a mini underground pool, for bugs and snakes?

      Tried and tested: 6″ of compacted roadbase type gravel.

      I have nothing against limestone. Never set limestone flagging before though. Does it hold up to your freeze-thaw cycles? If so–and if it’s sufficiently thick enough–then use it. hou

      Reply
25. 

    Sue Steinacher on March 22, 2024 at 7:31 pm

    We’ve already laid our free form flagstone (on sand on top of hard-packed gravel.) I’m off to buy fine gravel or screenings for the joints. What do you think of adding a little bit of Portland Cement mix to the fine crushed gravels? If yes, in what proportion? Thank you!

    Reply
26. 

    Sue Steinacher on March 22, 2024 at 7:33 pm

    We’ve already laid our free form flagstone (on sand on top of hardback gravel.) I’m off to buy fine gravel screenings for the joints. What do you think of adding a little bit of Portland Cement mix to the fine gravels? If so, and suggestions on proportions? Thank you!

    Reply
    • 

      Devin on March 22, 2024 at 7:52 pm

      I never approve of using Portland Cement with dry laid flagstone. If it’s on a concrete foundation: then portland cement based mortar for the bedding material and for the joints.

      But dry set flagstone is a far superior option. If laying flagstone upon a gravel foundation, then the joint material should be fine crushed stone/stone dust. Ants sometimes undermine stones that are set in sand, so I prefer stone dust as the bedding material, too.

      Reply
      • 

        Sue Steinacher on March 23, 2024 at 9:56 am

        I wish I’d found your website before we started this project! And that I’d known about stone dust before now. But I’ve found both now and will at least use the stone dust for our joints. Here in southern Utah they called it chat! Thank you!

        Reply
        • 

          Devin on March 23, 2024 at 11:15 am

          Chat is a new one, for me. Knowledge is a two way street 🙂 Thank you.

          Reply