Low greenhouse masonry - rock

[malbert]

Natural, unprocessed rock must be one of the most environmentally-friendly building materials:

1- It can be sourced locally just about everywhere so the energy required for transport is low.

2- Energy required for production is low compared to other masonry products. Rock rubble needs to be blasted and then undergo rudimentary sorting for size. It doesn't need to be cut, crushed, chemically treated or heated.

3- Rock is durable so the energy input during construction divided by the lifetime of the structure is low.

4- Large amounts of rock can be sourced from small areas. Quarry sites could be chosen from areas which have low economic and cultural values. If an already degraded site is chosen then at the end of the quarry lifetime it could be rehabilitated into something better.

5- There is far more available rock on the surface of the planet than could be used so I suppose it's a sustainable resource if not a renewable one.

6- Rock has a high thermal mass which can be managed to save energy in buildings.

7- Rock looks good! A good looking environment must be a good thing.

So with all the good things, why is rock rubble used so little today? Probably because of the high cost of the skilled labour needed to fit irregularly-shaped blocks together.

Have a look at my post on the Building, Architicture and Construction section where I describe a method to use natural rock rubble which might bring it's price down to be competitive with concrete and brick. Or have a look at my web site www.rocksolver.com

It's basically a method where a computer fits the rocks together in the virtual world and outputs instructions to the builder. I'm developing it as an invention but it is as yet just a concept.

Any thoughts, ideas, suggestions would be appreciated. Thanks.

[Mith242]

I really do like the look of stone too. My metro seems to be big on brick though at the moment. I admit though I don't know how environmentally friendly making bricks is offhand.

[malbert]

Mith, I didn't know either so I found www.greenhouse.gov.au/yourhome/technical/fs31.htm

which talks about the embodied energy of a building.

Some of the figures for energy of production in MJ per kilogram:

Local dimension granite - 5.9

Clay brick - 2.5

Kiln dried hardwood - 2.0

Concrete - 1.9

Stabilised earth - 0.7

Don't know about rock rubble but it might be low on the list due to low production cost.

A more telling figure is the energy in MJ per square metre of wall:

Double clay brick, plasterboard lined - 906

Cement stabilised rammed earth - 376

Timber frame, timber weatherboard, plasterboard lining - 188

Again, no figure for natural stone rubble.

These figures are estimates and the environmentally friendliness also depends on where the energy came from. I suspect mostly fossil fuels here in Australia.

[Mith242]

Mith, I didn't know either so I found www.greenhouse.gov.au/yourhome/technical/fs31.htm

which talks about the embodied energy of a building.

Some of the figures for energy of production in MJ per kilogram:

Local dimension granite - 5.9

Clay brick - 2.5

Kiln dried hardwood - 2.0

Concrete - 1.9

Stabilised earth - 0.7

Don't know about rock rubble but it might be low on the list due to low production cost.

A more telling figure is the energy in MJ per square metre of wall:

Double clay brick, plasterboard lined - 906

Cement stabilised rammed earth - 376

Timber frame, timber weatherboard, plasterboard lining - 188

Again, no figure for natural stone rubble.

These figures are estimates and the environmentally friendliness also depends on where the energy came from. I suspect mostly fossil fuels here in Australia.

Interesting, thanks for the info. I hadn't thought about all the energy required to 'fire' the bricks.