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Decomposed Granite Patios

I’ve done 100’s of decomposed granite patios and walkways in northern California and learned a few things as I went along.  When I first began, the industry didn’t have a ‘hardener’ that you could add.  That made for a semi-successful installation, because in the winter your walkway was mushy at best.  With the advent of hardeners, the DG comes out quite nice, with minimal mush.

Get the DG pre-mixed with the hardener (some landscape outfits will deliver like this) or mix on your own in a wheelbarrow per the proportion instructions.  Prepare a bed that’s about 5″ deep.  Use an attractive edging.  I am totally committed to Ryerson header, which is a thin hard steel that’s bendable.  That’s because it disappears.  It is expensive though, comes in 16′ lengths with its own stake. The other plastic headers are ugly.  An alternative are the many colors and types of Trek, which is a recycled plastic material.  Use the 1/2″ wide size.  The advantage is that its more bendable than the steel, but it doesn’t disappear, so its part of your project design.

Decomposed Granite Path

Decomposed Granite Path

Lay down several inches of road base and use a compacter to compact it very hard and tight.  Order enough DG to lay down 2″ on top, compacted.  Then here’s the secret:  apply the DG (with the hardener mixed in good) at the rate of 1/2″ at a time.  Then compact.  If you apply too thickly, the stuff won’t harden well.  The DG has to be moist when putting it down, but not sloppy.  Compact 1/2″ at a time till you have your desired height.  Sprinkle with water.

Another method I’ve used quite successfully was told to me by the contractor at Strybing Arboretum in San Francisco.  All their paths are done this way, and they get tons of traffic.  For this method, DON’T use hardener.  Apply a good road base foundation of several inches, maybe 3 or 4″.  Then apply only 1/2″-3/4″ of compacted DG.  Essentially this is a dusting.  You will have to reapply every few years depending on your traffic.  I used this method for a patio over 4 years ago and still have not reapplied.  I think this is a superior method because you completely eliminate any winter mushiness.  Even with a hardener there will be some mushiness.

Some warnings:  DO NOT try to apply a hardener after the fact.  I once went to a potential job where the gardener had installed a walkway, then put the hardener in after he was done. Oh my God!  What a mess.  The whole thing had to be removed and redone.

Decomposed granite path

Local fines used as Decomposed Granite

Closeup of local fines and 3 Rivers Paver inserted for effect

Closeup of local fines and 3 Rivers Paver inserted for effect

Next warning.  Do not install DG directly  next to an indoor situation.  DG tracks.  It’s granite and granite gets on your shoes and gets in the house.  You need at least a few steps (not many) before you go inside.  My son’s elementary school built a new gym for millions of dollars.  The landscape architect speced DG as the hardscape all around the gym.  That was a disaster.  All those kids tracked that DG into the new hardwood floor and ruined it!  They finally installed concrete as a spacer.

Decomposed Granite grey

Decomposed Granite path

Next, the materials.  Of course, every area is different.  DG in the Bay Area came in gray, gold, or dirt brown.  I’ve mixed them for different colors.  Don’t be afraid to experiment a bit.  A new rock came out on the market from a local quarry that was cheaper (DG is expensive.  Last I looked it was around $80/yard!).  I was able to get ‘fines’ and used that successfully with the hardener for a coral color.

Anoter view of sunken DG patio

Decomposed Granite patio with edging

Decomposed granite ryerson header edging

Decomposed granite patio and ryerson header edging

For patios, (see my complete post on patios)I usually don’t like to have a visible drain, so I put the drain(s) on the outside in the shrub area.  The exceptions are like the previous post with the photo of the sunken patio.  Of course, I had no choice.  But really, always remember your drainage.

One neat new alternative to DG is permeable concrete.  Its more expensive than ordinary concrete, but it is nicer, much nicer, on the environment.  Its fairly new and my understanding is that a good powerwash in the spring opens the pores and keeps it permeable.

Permeable concrete

Permeable concrete

Permeable concrete closeup

Permeable concrete closeup

If you found this short entry useful, but need more information, click on this link for my full downloadable eBook on patios and walkways, priced at only $2.99.  I’ve collected hundreds of real-life questions from do-it-yourselfers and all those questions will be answered in this short pamphlet.

I’ve also included information on DG  pricing, colors, how to customize colors, and drainage.  If you are not sure if you should use DG or another material, I discuss the advantages and disadvantages of concrete patios and their preparation, mortared flagstone, flagstone on sand vs. flagstone with DG, as well as how to prepare gravel paths and patios.  Chock full of information in just 46 pages with additional color photos.  If you like the eBook, please comment in the Amazon section.  I appreciate all my readers and thank you all very much.

Decomposed granite path Getty museum LA

Calstone pavers

Calstone Pavers using Slate squares as the ‘edging’

45 Responses

  1. When using the aroboretum’s method, do you have to compact the 3/4 first?

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    • For complete installations instructions, please read my eBooklet first on Decomposed Granite Patios. The short answer is you need to compact the DG. Not sure what you mean by ‘first’ as the DG is the LAST thing you do in the process.

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  2. Thanks for the information. Does it make sense for our gardeners to have installed the DG with stabilizers a year ago (lovely hardpack) and then suddenly to break it up and rake it? I think one team made a mistake as it was great to have the hard-packed DG around a shedding ficus tree and between a walkway/pool and a grassy area. Now we have loose material everywhere and they must rake rather than blow every week. Weeds/grass are coming up everywhere. This was a mistake, right?

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    • So it broke up on its own? Or the gardeners broke it up? Not clear from your question. If its breaking up enough to rake, then it was installed wrong. Just because they added stabilizer doesn’t mean a thing. They could have added the liquid stabilizer. Did you read my entry from October 29 2014 on stabilizers? Second they could have just laid the DG down thickly, all at once instead of how I recommend in my booklet. Third, maybe they didn’t install drainage, or maybe they didn’t lay down a gravel base. Not knowing anything about your situation, I cannot advise you. All I can say is buy my booklet and do it correctly next time. I’d advise you to hire a contractor who is licensed and bonded instead of ‘gardeners’ That way the contractor must reinstall your patio correctly no charge.

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  3. can I get this without a kindle or kindle download?

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  4. What’s a road base?

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    • road base is a mix of different sizes of gravel. This is what your county uses before it puts down the asphalt coating for the road. It is available at a landscape supply house

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  5. Hi, I found your site after our path was installed, so we didn’t follow the methods you prescribe. Our path is curved and edged with bendaboard. The problem is that the bendaboard expands and contracts, which is causing the edges of the path to erode. I there any fix to this? Or am I looking at pulling out the bendaboard and installing the ryerson header? Can the erosion be repaired?
    Thank you,

    Jim

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    • How many ‘sheets’ of benderboard did the contractor use? at least 4-6 layers is needed and recommended tied together with strong wire at intervals

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      • Leslie,

        Thanks for the reply. Sorry for the late delayed response. They used the off the shelf bend-a-board made of recycled plastic. I swear I can almost see it moving as the temperature rises, which in Walnut Creek pushes past 100 degrees several times in the summer.

        Sounds like I may be faced with replacing that edging with metal (or concrete, then repairing the DG.

        BTW, other than this problem, we absolutely love the look and functionality of our DG path.

        Jim

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        • I never use that stuff as its the cheapest stuff around and definitely not attractive. FYI, I always consult with the client as to what they want for an edging–colors, price, etc. If I were you, I wouldn’t use that contractor again because he didn’t ask your advice, although sounds like your DG was done correctly.

          Why don’t you use 1″ trek to replace it. Not that pricey and much more attractive, with lots of color choices. That is my first go-to edging when people don’t want to spend much. The cheapest solution is wood benderboard tied together with wire at intervals, and as I said above, you must use about 4-6 layers, but it’s more bendable than the trek or the metal. Unfortunately, wood, as you know, will eventually break down and rot. It shouldn’t be too much work for you to replace that.

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    • For erosion repair, see my post on DG-a new improved stabilizer

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  6. I had my front yard redone with decomposed granite a couple of years ago. The plants are OK, but the trees (2 palos verde and a weeping birch) seem to be dying. I broke up the granite around their bases. What will help?

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    • If you look at my post called Patios hard and soft, there is a photo of a weeping willow with DG right up to the base. Since I am not at your site, I really cannot say what exactly is going on. DG is a porous material, especially if done right. In that site pictured above, we put down only 1/2″ of DG and the rest of the 5″ was base rock. This site had drainage problems as it sat at the bottom of a hill and right above a perennial creek. Therefore too much DG, the common recommended 2″, would have just become mush in the winter.

      Now you describe two different trees with opposing water needs. Birches are not native to CA (sounds like you live in SoCa as Palo Verdes will not grow in cold climates) and need an exorbitant amount of water. Birches have a lot of diseases and in Northern CA if a client requests one, I no longer plant eastern birch but Himalayan Birch which is more resistant to birch borers. So maybe that is your problem there or lack of water. As far as the Palo Verdes go, they are low water so have a different water need than your birch. One thing you should check is did the contractor who installed the patio put it at grade level with the trees or did he raise it around the collar? You know if you mulch a tree above their collar, you will kill it and that goes for any material including DG, so that could be your problem.

      DG with baserock done correctly is a porous material and allows water to flow through. I suspect your contractor or installer raised the ‘dirt level’ with the DG and therefore suffocated your trees.

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  7. I have a DG patio and path. Misread the instructions and waited 6 hrs after initial stabilizer (technisoil g3) instead of 30 mins. it hardened of course, and is now coming up in clumps. is there any way to repair, short of pulling all the DG out?

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    • First, please read my entry on stabilizers and G3, which cracks and has a lot of problems. You should first, call the company that makes the G3 and ask their advice. I suspect you will have to break up all the clumps, regrade and re-compact. Once that is done, spray on top with this expensive, but quality stabilizer called TerraKoat. The instructions for rebuilding an existing surface with TerraKoat are in the Addendum of my DG book available online as an eBook. I would not use the G3 again.

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      • Thanks, will read. I did contact the company and they said either (a) scrape off the clumps and apply top coat or (b) rake it all and re-apply. Having wasted hundreds of dollars I’ll pass on both options for now and let nature take its course. in a couple years, when G3 is mostly gone, I will reassess and when I do, choose a different product…. thanks.

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        • Just to follow up – I had already bought the G3 and was getting pushback on returning it. I raked it, reapplied and re-compacted. It is working. Not perfect, but good enough. I think my bigger mistake was to use that recycled plastic edging. It expands when the DG does not, and cracks form. Oh well.

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  8. I wish to do the Arboretum method. Should all the base gravel be compressed at once before the DG fines are applied and compressed on top or should it be compressed in layers? I am using it for an upper patio. Also, will oak tree leaves stain it? Most of ours have fallen or died with the drought and heavy rain of December in N.California. However, some of my neighbors leaves fly over in fall. We have Japanese maples as well. Plan to clean up as quickly as possible. Time is of the essence. Just decided to do this instead of gravel as it looks so much easier to walk on, and because of a transition from path to pavers on a slight grade. Don’t want anyone slipping! About to order for next week! Thanks!

    Like

    • You can read the exact method in my eBook. But apply the gravel half at a time, using an electric compacter for each half. I’ve never seen leaves stain DG. Just use a blower or rack to move them off the patio.

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  9. I have a reverse decomposed granite issue. Apparently dg was installed as the base layer for a layer of asphalt in my backyard. I’m an avid gardener so soon after I moved it I took out the asphalt to garden. The layer underneath seemed to be fairly organic looking so we just dug holes to put plants in wherever we could get a shovel through it, planted several trees here and there, and went on with life.
    I have one area along side the deck which really needs to be planted but due to the gravel / rock layer I just having pots. Finally, I decided to remove the entire dg layer. I’m finding the easiest way, and it’s not easy at all, is to undercut with a mattock. Is there anyway to soften up decomposed granite?

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  10. I have a contractor that just put in a small DG patio in my front yard, but the gravel is VERY loose (and now its wet from two days of rain here in So Cal)…he recommends spraying some type of glue on it and then tamping it down again. Have you ever heard of such a thing?

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  11. I am in Northern CA (Sonoma). I read your book and have been following the Arboretum method on my DIY project (which is a complete lawn removal – approx. 2500 square feet to be replaced with DG). I scraped what was left of my 3 year drought tortured lawn, dug down 3″ to 4″ and built several raised planting beds to hold the soil. I have layered and compacted 3″ to 4″ of road base. The whole thing is bordered in with a combo of concrete patio edges, rock wall edges, planter bed edges and some wood edges. So far so good I think.

    I noticed that compaction on my road base can vary from very tight (where there are lots of fines and compacted when moist) to firm but subject to movement in areas where there are more rocks (if my dog makes a hard turn while chasing a ball, he can leave a small divot).

    When I put down the DG (1/2″ to 3/4″ compacted) will the surface maintain compaction or will it loosen and let road base gravel work its way up if my dog makes a hard turn on it?

    thanks,
    Jeff

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    • Hi Jeff, well not being there that is a hard one. Did you use an electric compacter? That would definitely help. It might happen that yes it would leave a divet somewhat there. DG is not perfect and in fact it can leave rivulets from rain etc. I would suggest 1. compacting with an electric compacter and misting it in between if you haven’t used one yet 2. putting the DG done as suggested in the book and seeing what happens–again with an electric compacter 3. if you are still having some sloughing off them use the TerraKoat hardener afterwards which is a spray that you can spray on top at the end. The TerraKoat will solve any of those problems and you can determine later if you need it or not.

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      • I’ll keep to the method you outlined in the book and see what happens.

        I have been using a heavy gas powered compactor. I did try compacting some DG samples I brought home for color selection but there was not enough to get a good test. I did notice the DG worked its way down into the road base so maybe it will help lock it all in.

        If not I’ll look into the terrakote but that was not in the original budget!
        Thanks for your book. I would have made several mistakes without it.

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        • Would there be a downside of having stabilizer added by my landscape materials supplier (the powdered kind) from the start? I know the arboretum method specifically says do not use stabilizer but does it create any problems if I do?

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          • Well, you usually just do not need the stabilizer with so little DG but it wouldn’t hurt to add it. I might do 3/4 to 1″ if I added the stabilizer. I’ve done the arboretum method with no stabilizer with even 1″ of DG because my landscaper didn’t follow my instructions because he was afraid. It turned out just fine. Stabilizer wasn’t even ‘invented’ until around the early 2000s. People used to put it down in the beginning without any. My own yard I did a DG path in 1996 with 2″ of DG when stabilizer was not available. It was somewhat mushy in the winter but held up fine for 20 years. So, yes to your question. If you want to include some stabilizer in your 3/4″ then there is no problem there. I just don’t think it’s necessary.

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  12. Thanks for the reply. One more question (I think!). What is a typical compaction rate for DG when laid down over over compacted road base? (Using a heavy duty gas powered compactor). I have been using an online gravel estimator to figure out how much material to buy and on some of them you can enter a compaction rate. So if I wanted to end up with 3/4″ compacted DG what would that be loose?

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  13. I started to create a DG path last week, but upon compaction, it all turned to mush. The first layer seemed to work fine (we used a drum roller to compact as we needed to install over a couple of days and could not afford to rent the vibrating plate compactor twice). We then put on a second layer (1-1.5″ thick), screeded to the proper level, then attempted to go over it with the vibrating plate compactor. Muddy mush! We had dampened the DG the night before (over 12 hours), but couldn’t understand what happened. (It had rained the weekend before, so I’m wondering if the sub-based was just too damp still).

    1. Do you have any ideas of what may have gone wrong?

    Also, in an area where the vibrating plate compactor did not fit, we used a hand tamper. This area turned out looking nicer on top, but it still had some cracks.

    2. Do you have any suggestions on how to repair the cracks? (I tried filling in the crack with dry DG, wetting it, waiting, then tamping. This only resulted in smaller cracks the next day).

    I am starting to question whether the yard send us DG at all, or some dirt/DG mixture. Your feedback is appreciated.

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    • Lila, did you read my entries on DG or my book? You do not mention how you did your road base and how many inches of it. You didn’t mention how you compacted the road base, nor if you accounted for drainage for your path. You also said you applied it at 1″-1.5″ thick at a time which is not what I recommend in my book or my entries. You’ll have to start over, remove all your DG and maybe reinstall the road base, if you even used that. Did you have stabilizer in the DG that the landscape yard pre-mixed? What kind?

      Sorry, but you have not given me enough info. I recommend you start over using the methods I outline in my eBook.

      Here is a quote from my eBook about your same problem:

      There are several things that could have gone wrong. 1. Temperature too cold when applied 2. DG was not sufficiently mixed with stabilizer and so the stabilizer just sits on the top 3. Your contractor is using G3, a liquid stabilizer, which cracks a lot and has a lot of problems 4. Not compacted correctly in the first place and 5. Any combo of the above.

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      • Unfortunately, I did not find out about your book until AFTER we began installation. Per a local landscaper, we did not need road base as long as we sloped the surface properly. We did not use stabilizer, as it has such mixed reviews.

        Sounds like we will have to dig it up and start all over. Not looking forward to the extra work, but we want to get it right. Thanks.

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        • Lila, is your ‘landscaper’ a contractor? Did your ‘landscaper’ do the work? If both of these are true, then you would have recourse. He would have to fix it and do the work properly on his dime. I always recommend a licensed and bonded contractor for ‘hardscape’ work just for this reason. You can check their license with the state beforehand to make sure it is active and real

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  14. Leslie, I’ve read your book but I”m still unclear on one thing. You say mix the DG with stabilizer before it is laid down. Do you also then mix water in so that it is damp not sloppy before it is laid down?

    Also I’ve already laid about an inch and I’m guessing I’ve not used enough stabilizer because 5 days later the DG is not uniformly hard. Fortunately I have another 1/2 to 1 inch to go before I’m finished. Should I just lay the new DG on top of what I’ve already laid without applying anything further (i.e. stabilizer or water) to the base layer of DG that is already down?

    Thanks

    Like

    • Since DG and also the stabilizer are powders, you have to mix them first in either a wheelbarrow or cement mixer, then apply water so it is, as you say, damp not sloppy before laying down and compacting. I hope you compacted the DG 1/2″ at a time as that is the secret. You certainly can apply another 1″ (1/2″ at a time) without stabilizer and just know that without stabilizer in winter rains it will be mushy. I would suggest using TerraKoat which is a stabilizer that is sprayed on, or watered on, AFTER the DG is set down since you already began your project. That way you know that your entire project has a hardener rather than only the top half. It will probably turn out much better that way.

      Like

      • Actually the stabilizer I have is a liquid called Gator Stone which seems to be applied in the same fashion that TerraKoat is. I was advised by the yard I got the DG from to water the area prior to laying DG (yes, in .5″ increments) compact, apply the Gator Stone and sprinkle with water. So that’s what I did.

        I can sink my finger up to the knuckle into the two .5″ layers laid in some areas, so I am guessing I underdid and wasn’t uniform with the Gator Stone I sprayed on. I am thinking to not touch what is already laid but build on top of it the final 1″ (in .5″ increments) following the same steps as above, but just use more Gator Stone and be more uniform at the end of each increment.

        Do you see any other steps that I am missing?

        Thanks

        Like

        • Nick, just looked at the Gator Stone website and it didn’t appear to me that they specialized in DG stabilizers but more like hardeners for various other modalities. Maybe that was your problem.

          Like

  15. Sorry, but I am not familiar with Gator Stone. In general, I do not use liquid stabilizers as they are usually watered down as in the G-3. This Gator Stone is not used like the TerraKoat which is applied afterwards, not before. See my post https://thehumanfootprint.wordpress.com/2014/10/29/decomposed-granite-stabilizer/

    In this case since you are using a product that your yard provided, I would advise consulting them.

    You can always break up the DG if the Gator Stone did not work and then apply the TerraKoat which I know does work

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  16. Leslie, thank you for following up on all of these questions. They have been really helpful. I now have two questions: 1.) I live in Massachusetts and would like to do the walkway like the one you show at the Getty Museum. I am wondering, since our winters are cold and snow can get up to 20 inches, if this walkway would work, if I had to use a snowblower over it? 2.) I read the TerraKoat site and noticed they offer a Bonding Agent, which can be used without a foundation of aggregate; have you ever created a walkway with the bonding agent and only 2″ of the DG?

    Like

    • Not familiar with Mass. but I do know that DG does not do well in areas with a lot of winter moisture. Talk with your local landscape yard. It’s possible that DG is not even sold there because of excessive moistures as well as freezing and thawing.

      Sorry, not familiar with the bonding agent. I’d suggest calling the company and speaking with them directly. I would suggest TerraPave as that hardens up like asphalt, but it is only available in Northern California.

      Like

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