DG Patios–Decomposed Granite

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.

DG path using gold fines with low cost header

DG path using gold fines with low cost header

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.

Local fines used as DG

Local fines used as DG

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.

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.

Gray DG with Ryerson edging

Gray DG with Ryerson edging on one side and wooden PT rounds on the other

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.

Sunken patio with Ryerson header edging an a granite block decorative edge

Ryerson header and granite block decorative edge. Gravel and paver at left

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.Anoter view of sunken DG patio

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.

Getty museum LA DG path

Calstone Pavers using Slate squares as the ‘edging’

About these ads

13 Responses

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

    • 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.

  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?

    • 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.

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

  4. What’s a road base?

    • 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

  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,


  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?

    • 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.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s


Get every new post delivered to your Inbox.

Join 214 other followers

%d bloggers like this: