What can you tell me about DG (decomposed granite) relative to RMH's?

I'm looking for some info on DG as a material, it has both quartz and feldspar, seems to be opposite thermal matials


Good for cob?
Thermal or insulative?

Good for slip when screened down?

In a green house application, where the entire earth floor is natural packed DG, should I insulate at the base of the thermal battery??
Or can I begin the build with the 8 in pipe directly on the ground?
( I imagine I will be using the battery centered in the hoop house as a bed warmer, plants arranged on top, water barrier separated)


I believe I will be using large river rocks, filled in with pea gravel and clay/dg slip as my mass

Oh and....

I have been looking on line for info

One point of interest is that for patios, contractors add a hardener before compacting
Which is also available in an Eco friendly compound
Keeps it rain resistant

May have application here...

granite has a pretty good heat capacity. I used DG, mixed with clay slip, for my mass. easy way to make it monolithic.

I served in the US army engineer battalions for twelve years primarily as an equipment operator. I have also been the NCO for the 'embankment and compaction' squad in my platoon. On the civilian side, Ive built many, many very large and tall (80' X10' average) concrete block retaining walls. I have also installed cement and block or paver patios. All of those go on top of some variation of compacted base. I have never seen nor heard of using a 'hardener' before compacting. If the base material is made for compacting, nothing except adequate moisture content is required for upwards of 90% compaction. Appropriate base material will be called something like "2 inch minus", meaning the maximum size will be 2 inch. the 'minus' means that the rest of the aggregate will vary in size all the way down to a powder, also called 'fines'. This will also be crushed to produce angular surfaces whcih interlock during compaction. 2b gravel (2 inch round river rock) will not compact. Same thing with sand. play sand is milled to be round. Course paver sand is crushed material that will lock together under compaction methods. You do need moisture to help the different sized particles move into place.

You said your property is already natural DG, and is likely already compacted naturally to like 90%. Without any hardener. I insulated the base of my thermal mass from the garage floor. I didnt want heat going to warm the slab before it warmed the mass.

I dont think an RMH has any impact on granite. I defiantly cant see how it would make a rock rot.

however; I do know granite makes good aggregate in cob.

Good info on compacting materials for mass.
Water to get things arranged makes sense

My curiosity of locking and "play"sands, answered

I'm going to just take my chances and experiment

I found very rich clay patches
I'm going to fine screen the dg for slip

I'll keep updating as I go

I'm not sure anyone answered your original question, but the difference in thermal quality is not really about the minerals here, (quartz and feldspar) but the density of the finished mix. Loose material will have an insulating factor because of the air. Water will help it move in closer and fit tighter, but will eventually dry out leaving spaces. A solid material with the DG as an ingredient will be thermal, unless huge quantities of other insulating materials, vermiculite, sawdust, perlite etc. are added.
Also, I'm not sure what you mean when you say slip from screening, but the amount of clay-like particles would be miniscule from a massive amount of effort and the result would have very little plasticity (or strength) anyway after drying.
I just described a way to test/use found clay here: https://permies.com/t/21225/rocket-stoves/Sand-mass-RMH This might be help.