A blog about the restoration, remodel and renovation of a 1929 Chicago-style brick bungalow

Having Gator Dust Problems?

In addition to lots of hits on the differences between Benjamin Moore’s Aura and Natura paint lines, I also get a lot of hits from people searching “gator dust problems”. No one seems to use more specific search terms, so I’m not sure if they’re having Gator Dust problems or are anticipating/trying to avoid problems.

Either way, we have used Gator Dust twice now: the first time when we moved our patio from our previous house, two doors away, and about a month ago when we expanded the same patio a little.

If you’re unfamiliar with Gator Dust, it is similar to jointing sand for pavers, but is used in cracks that are much larger, like with the irregular shapes and cracks in flagstone patios. The Gator Dust has a hardening agent/binder that is activated by misting with water. Once dry, it still has some flex to it to allow for some movement of the stone, especially in freeze/thaw areas like ours.

Overall the Gator Dust that we applied 5 years ago has held up well. There has been a little wear, and we could pry up some pieces in spots, but we have had very few weeds making their way into cracks. Since we were about to apply more Gator Dust to the new section, I wondered if it was possible to reapply Gator Dust and build it up over old Gator Dust. I couldn’t find any information on it, so we figured we’d try it and see if it would work.

It comes in two colors: beige and gray. We’re using gray. We poured the Gator Dust into smaller tubs and tried to concentrate on pouring it into the cracks, although I think the instructions say you can pour it on and sweep into cracks. It contains a mix of larger pieces, around small pebble/limestone screening size, down to a fine dust.

We brushed as much as possible into the cracks using a wire brush and pounded the stone with a rubber mallet as we went along. You want to get as much as possible into the cracks, and pounding the stone helps it settle and remove air pockets.

Then you need to thoroughly sweep the dust off the stone. We tried the leaf blower at a low speed to blow it off the stone, but I didn’t think it worked that well. Our leaf blower isn’t the best, so maybe you’ll have better luck. I ended up using a Shop Vac, getting as close to the cracks as possible without sucking up the Gator Dust.

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You’ll end up with the stone looking pretty much like this.

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Even with vacuuming there will appear to be a fine layer of dust but it didn’t seem to be an issue on the stone once we sprayed the Gator Dust to activate the binder.

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And here it is after we misted the patio (follow the instructions on the bag for misting frequency). The area at the far end is where we laid the new stone — obviously the old flagstone could use a good cleaning.

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We do need to fix and build up some spots. You want to make sure that there’s a good mix of fine dust plus the bigger pieces in the cracks. In the photo below, the cracks to the right have too many big pieces, so there wasn’t enough binder to harden them — we’ll have to vacuum those up and reapply. The crack on the left has a good combination of dust particles to pebbles and has solidified. We also found that it was possible to patch in new Gator Dust with old spots.

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I hope this has been helpful. If you’re having problems with Gator Dust, feel free to ask a question and I’ll do my best to answer.

25 Comments

  1. Jim Reilly on November 14, 2013 at 4:52 pm

    I had a patio laid with flagstone and gator dust a month ago. The joint sand is still soft in spots, can be scraped out with a fingernail in places and some stones move when stepped on. The joint widths vary from 1″ to 6″ or 7″. How long does the dust take to set and cure?

    • denise on November 15, 2013 at 9:06 am

      Hi Jim–
      Sorry you’re having issues with your flagstone patio. According to the manufacturer, the gator dust continues to harden over time although they don’t seem to specify a certain length of time. I just checked ours and it seems pretty hard, so that’s been about 2-3 months. There are spots that flex a bit though (in larger joints of about an inch), and I could potentially scrape away some of the top layer with a fingernail (some of the particles that didn’t seem to bond well), but it definitely wouldn’t easily scrape completely out. I believe it’s designed to have a rubbery flex to it in order to compensate for freeze/thaw and ranges in temperature.

      If it doesn’t harden, however, it may be due to “over-wetting” the joints. They are supposed to be misted lightly several times. The joint widths are supposed to be a maximum of 4″, so having widths of 6-7″ could also be a factor. We fit our stones together like a puzzle, trying different pieces to get them to fit together as tight as possible. I don’t think we have more than an inch in most spots and we also filled some gaps with small pieces of flagstone to bridge those gaps.

      As for stones moving when stepped on, unfortunately I believe that is the fault of the installer — we carefully laid each stone and had to adjust the base sand or screening to level each one by picking up the stone and adding or taking away screening (sometimes it took several tries). No two flagstones are the same thickness, and one side of each stone could be much thicker/thinner than another side. Once it seemed level, we stood on each one to make sure it didn’t rock. It’s very time-consuming but an important step. The Gator Dust won’t make up for that.

      I would wait and see what happens in a few months (or next spring if you’re in a colder climate like us), and if you can still easily scrape out joints, you should probably remove them and start again, making sure everything is nice and dry to begin with and then reapplying Gator Dust, making sure that the joints are lightly misted according to the timing in the instructions. As for the moving stones, those would have to be re-leveled before you reapply Gator Dust.

      Sorry it doesn’t sound like an easy fix — the product itself has worked really well for us over the years. We used limestone screening in the joints of our first patio at our old house and the Gator Dust works much better. Hope this helps, and good luck.

  2. Jim Reilly on November 19, 2013 at 4:13 pm

    Thanks very much for replying. The more I examine the job, the more convinced I am that it was a botched installation that did not follow the product manufacture’s requirements and instructions.

  3. Kathryn on July 26, 2014 at 7:45 am

    Just read your blog entry about Gator Dust. Wondering if you applied additional dust over existing (old) dust or if you removed the old from the joints to apply the new. I just did a patio and I think I over-watered and also didn’t fill the joints enough, so I was thinking I might add more material on top of the old and water very lightly.

    • denise on July 26, 2014 at 8:50 am

      Hi Kathryn! Yes we applied additional dust over old dust, however for the most part the existing joints were still solid and we just wanted to build them up a bit (the old stuff was several years old). There were a few spots where we dug out the old stuff and redid them because they had separated from the stone. I think I’d be reluctant to add more over yours if you really did overwater it. If you just did it though, I might suggest waiting a few weeks to see if it hardens before adding more. Unfortunately I can’t say for sure either way if it’ll work or not, sorry!

  4. Dennis on July 28, 2014 at 11:47 am

    We recently installed a ptio and added gator dust. Now some areas with gator dust looks as though mold/mildew has set in. Does the gator dust need to be removed or can it be cleaned with a solution.

    • denise on December 27, 2014 at 10:40 am

      Hi Dennis, sorry I never responded! Hopefully you were able to find a solution to your mold/mildew problem. Is it mold/mildew or moss? I would imagine that moss might grow in the cracks if it’s continually shady and the Gator Dust remains somewhat moist. I don’t really know if you’d have to remove the Gator Dust completely, but if it were me I would first try cleaning it thoroughly and then add another layer of Gator Dust to build it up higher so that moisture doesn’t settle in the crack. Good luck!

  5. Dave on October 11, 2014 at 12:37 am

    Hi,
    Just spent $10,000 on beautiful antique rustic stone, that now looks very washed out as a result of the Gator Dust. The leaf blower just created a cloud that settled over the patio. Is there something I can use on the stone to get the rich tones back that seem to have vanished due to the gator dust?
    Thanks, Dave

    • denise on December 27, 2014 at 10:34 am

      Hi Dave, Sorry I dropped the ball on your question. We didn’t feel that the leaf blower worked very well which is why we did it by hand. I’m sorry to hear the Gator Dust dulled your stone. I’m afraid I can only speak to our experience with it, so it’d be best to speak to a professional about options. Were you able to find a solution? I wonder if a stone sealer would remedy that?

  6. Joel on August 3, 2015 at 1:43 pm

    Darned thing took off before I was done writing. Just installed over 800 sq ft. of new paver. Our joints are tight, less than the 1/2″ in the Gator Dust Instructions. Also cautious about the dust hazing discoloring of my blocks. What are your thought on these subjects?

    • denise on August 3, 2015 at 2:09 pm

      Hi Joel! Without seeing your installation, unfortunately it’s hard to say. I can only speak from my own experiences, and I would say to REALLY take your time in getting the Gator Dust off the pavers. We didn’t care for the leaf blower approach and felt it left too much behind. No matter how careful we were, it still appeared to leave a super fine dust on the stone but in our case it didn’t seem to affect the look. Another thing to note is to follow the misting times exactly per directions–we were very careful about doing that. Also be sure that none of the bigger pieces in the Gator Dust are sitting on the stone or those will likely adhere because of the binder. Do you have extra pavers where you can set up a little test area to see the results before you do the entire patio? If so, I would do that to be sure you know what you’re getting into. I hope that helps–I know it’s kind of nerve-racking! Good luck!

      • Joel on August 3, 2015 at 6:44 pm

        I do have a few extra pavers to try it on first. My other thought was to go ahead and seal the pavers with a coat before doing the sand, kind of like a grout release, so that there would be a coat of sealer on the pavers before putting the Gator on them. I was hoping that it would allow the sand to clean off the blocks better. Maybe I should be careful not to get the sealer too much in the joints??

        • denise on August 4, 2015 at 7:28 am

          That might be a good idea if you had planned to add a sealer on it anyway. Did you check the Gator Dust FAQ page? I don’t recall seeing that before, so that might be helpful for you.

  7. John Buckley on October 11, 2015 at 1:40 pm

    I installed gator dust on 300 sq ft of flagstone walkway yesterday, and am concerned about the results. While most of it looks okay, there a number of spots where (1) there are air bubbles under the wet layer of dust, dry underneath, or (2) the product almost seems to have expanded, and pushed up out of the joints. Also, though temps were in the 80s – and even warmer today – an area on the north side of the house (in shade) is not setting up at all. I followed instructions as carefully as I could but still found it hard to tell whether I was using too little water or too much. I suspect it may have been too much. What kind of problems have I created for myself?

    • denise on October 11, 2015 at 2:27 pm

      Hi John–I’m certainly no expert on differing gator dust conditions/issues; I can only speak to our limited experience and speculate on others’. With the bubbling, it does sound like too much water–we used a VERY light mist and never got any bubbling. Did you pound out the air bubbles with a rubber mallet next to the joints as you went along? If you did use too much water, especially on the north side then I’d imagine it won’t set up easily. I would think the worst that could happen is that you have to scrape out the bad areas and either redo it with gator dust or replace it with limestone screening (which we used the first time we built our patio, and it held up pretty well) or something similar. We’re going to have to redo some joints ourselves I’m sure; with something like this exposed to the elements there’s bound to be some upkeep no matter what material(s) you use. I wish I could be more helpful but hope it works out for you!

      • John Buckley on October 12, 2015 at 3:34 pm

        Thanks for the input. Yes I was very diligent about tapping all the stones – three different times – per the instructions. Yesterday afternoon the temperature got above 90, and I set a fan to blow on the area on the north side that was still wet. It looks fine today. Actually the whole thing looks pretty good, except for a few spots where there are small bubbles, and a couple of places where the material kind of bulged up slightly above the stones. I’ll just have to wait and see how it looks in the spring.

  8. Tammy on November 19, 2015 at 4:44 pm

    I’m waiting till Spring to see what happens. I laid my patio with Gator Dust this last October and it looks great! Two weeks after laying it my husband was sitting in a chair and two of the legs of his chair sunk into the cracks. It’s as though it only hardens about a quarter of an inch down. Not sure if that’s normal or not. Hoping more hardening will take place this Winter. However, I did want to mention that a power washer worked great for us in cleaning away the dusty film off the top of the flagstone. Leaf blower was pretty pathetic. It’s important to make sure your Gator Dust has had some time to really harden and we purposely stayed away from the cracks but got as close as we could to the edges. Easy to do and quick!

    • denise on December 23, 2015 at 8:49 am

      Hi Tammy, Thanks for sharing your experience and sorry it took me so long to respond to your comment!

  9. Bernie Hillengas on June 2, 2016 at 1:14 pm

    Hi Denise,
    I am about ready to apply Gator Dust Bond to a patio I installed with varying shaped blue stone with joints ranging from 1/4 in to 6+ in. I am curious; how many sq ft is your patio and what are the range of joint widths? How many bags of Gator Gust did you use?

    Thanks and best,
    Bernie

    • denise on June 9, 2016 at 9:06 am

      Hi Bernie–So sorry, I wasn’t notified that you commented last week! I don’t think we used more than one bag (can’t say for sure though; it’s been a while!). Our patio is probably about 250 SF. I’m a little concerned about your 6+ inch joints though–our joints are pretty tight; the biggest is probably 1″. I just checked their website and it looks like their latest product allows 1/2″ to 6″ joints so hopefully you’ll be fine. Let me know if you have any other questions, and good luck!

  10. Chris on September 5, 2016 at 2:56 pm

    I just finished laying a flagstone walkway and would like to apply the gator dust in the next couple of days. I have two questions maybe you can help me with:
    1. I have pulverized limestone in the joints up to about 1/2 or inch of the top of the stones. Do I need to remove all of this crushed limestone before applying the gator dust?
    2. The walkway is curved so in a few places I have some small triangular stone, some maybe with 3 inches sides in order to fill in gaps along a curve so I have a fairly straight edge. I’m concerned these pieces won’t stay in place as they are on the edge. Do you have any experience with small pieces on the edge of your walk/patio?
    thank you!

    • denise on September 6, 2016 at 7:32 am

      Hi Chris! I think the pulverized limestone will be fine as is, as long as the Gator Dust layer isn’t too shallow. 1/2″ or more seems deep enough. Regarding your other question, a 3″ piece should hold okay but I guess it depends on how rigid the ground is next to it. Our patio is surrounded with an aluminum edging which separates the stone from the soil so the edges are pretty rigid. We have small stones filling in big gaps in various spots and they seem to hold up pretty well. Hope that helps and good luck!

  11. Chris on September 6, 2016 at 9:35 am

    I wish we would have used the metal edging. I see the advantages now in finishing the job. 20/20 hindsight. I do have a pretty rigid edge in dirt so going to keep my fingers crossed.
    And great news in that I dont have to remove the crushed gravel. Some of my stones are pretty thick so this definitely will save me time and extra gator dust.
    Thank you so much for your response.

  12. Robert on October 7, 2016 at 6:56 pm

    Hi –

    I installed gator dust in the cracks of my flagstone. Followed all instructions. The top of the joints has a flexible feel about an 1/8″ think.
    The main problem is that it is not setting. So when it rains the gator dust is like wet cement. So what would you recommend I do now? Scrape out the top 1/8″ and use what??
    Thank you

    • denise on October 28, 2016 at 8:14 am

      Ooh, that’s a tough one. My advice is really limited to our own experience—since we didn’t have that problem I really don’t know what to suggest. My best guess is that it got too wet, but that’s really just a guess. Have you tried contacting the manufacturer? I wish I could help more, and sorry I missed your comment earlier!

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