# Forum Home Renovation Landscaping, Gardening & Outdoors  Decomposed Granite driveway

## kaliani

Hi, 
We are busy getting quotes for laying a decomposed granite driveway and side path. The guy who came to quote didn't know what decomposed granite was.  
He said he thinks what we want is 'crushed concrete' or 'aggregate'. Can anyone tell me if this is the same as Deco-granite? (as in picture below)   
We don't want to end up ordering the wrong thing - worst of all end up with a concrete or pebblecrete driveway!! We quite like the English cottage garden look of the deco granite.

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## echnidna

Its totally different to  'crushed concrete' or 'aggregate' 
It may not be available in your region.

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## elphingirl

Have a visit to your local garden supply place (or two), and look at what they have. Decomposed granite has some different names, depending upon where you are, and often there are great local aggregates available that will do the same job, don't travel too far, and will look 'comfortable' in the local environment.  When you get the contractor to do the job, make sure you specify the product they are to use (and to what depth), so you don't get any surprises.

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## Planned LScape

Some people call it Granetic Sand, most landscapers use that in the south not sure about north. It goes hard as a rock, but still is susceptable to being soft after rain and it can wash away and form little rills in the surface. Trick is to make sure the base is right with a proper compacted crushed rock base. 
It's better to try avoid using it on slopes, but you can get a product called Soil Bond which is a natural bonding agent which makes it hard yet flexible. It's tedious though, it has to be mixed in, preferably in a mixer or agitator to get a good mixture.

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## kaliani

thanks for the replies so far.  
Does anyone know what other terms might be used for Deco-Granite in Sydney? As mentioned, our landscaper doesn't seem to know what we are talking about.  
Thanks

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## Vernonv

Maybe the best bet is to go to a gravel/sand supplier (the people that quarry it) rather than a landscape supplier.  
We went to our local supply mob and asked for deco-granite and they didn't know what it was. However when we went and looked at what they did have we realised that they called it by it's local name ("Black Mountain Gravel") - but it was the same stuff (or at least very, very close to).

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## notenoughtoys

My experience is that you need to use someone who  knows the product. I have a crushed granite drive, or at least did. The guy that did it initially did a great job. It was stable and firm. Sydney Water (contractors) came through 12 months ago laying sewer pipes and went straight up the guts of the driveway. Now it is spongy, turns to slush when it rains and weeds grow in it. They have re done the job twice and now just ignore my calls. I'm not sure what they did differntly to the original supplier but the two jobs are chalk and cheese.   :Doh:

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## Bluegum

> thanks for the replies so far.  
> Does anyone know what other terms might be used for Deco-Granite in Sydney? As mentioned, our landscaper doesn't seem to know what we are talking about.  
> Thanks

  
 Most of the blokes I know just call it Deco for short.  up here it tends to vary in price but as already suggested put it down on a good compacted base first.  I would suggest boxed in road base compacted and then your deco over the top of it.  A good bobcat operator will get your fall right as well as the depth.  I'm going to throw down straight road base due to the movement in the soil that I live on and a mate of mine reckons he knows where to get road base for $10 a metre delivered so I will take him  up on his offer.

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## Bleedin Thumb

The trick with Deco is (like all paving) the prep. You need to have a compacted, stable* sub-grade* covered with a *sub-base* equal to DGB 20, at least 100mm compacted thickness compacted to 98 % density. 
The Deco should be no more than about 50mm thick, cement or lime stabilized and compacted at the correct moisture content preferably with a ride-on type roller. 
Watch how much trouble those crews go to to make a road..... that's what your doing with your driveway

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## namtrak

Decomposed granite or crushed granite is exactly that.  Granite rock which is crushed and reduced to smaller particles.  Once it is packed into driveways, paths etc it sort of reforms to a degree and becomes rock hard. The clay content in the granite is a very important component in the binding (The problem with the contractors who dug up the middle of the driveway is that they have broken the bind between the granite and now it would be almost impossible to recreate that bind) 
Crushed concrete is also exactly that.  Concrete blocks and slabs which are crushed and reduced to a much finer component.  Because there is no clay in the crushed concrete it doesn't bind, like decomposed concrete, and is more often used as roadbase which it is overlain with formal road surfaces. 
Aggregate is the smaller pebbles used largely as an additive to concrete mixes.  Once again, no good for driveways and so on, as it doesn't bind like decomposed granite does. 
Cheers

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## Bleedin Thumb

I actually like the recycled road base, (the rated stuff) which is aggregates of various sizes and fines which if you wet it down sufficiently and then compact it _does_ bind almost as hard as concrete.....don't know how ...but it is almost as if the concrete powder acts as cement......not possible I know but I swear that I get better compaction than road base made from quarried Basalt. :Confused:

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## namtrak

Your probably right, maybe they have an additive during the crushing process?  I'm not 100% sure, but the crushed concrete from a local mob here is very 'dry' and used almost solely as roadbase.

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