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Fundamentals: The greenest construction materials/techniques
I've put this under the 'Fundamentals' heading as it seems that there can't be much more fundamental on a green building forum...
A truly 'green' building must be one that is 'green' in terms of the extraction of raw materials, manufacturing processes, transport, energy consumed, impact on the environment, ecology, the energy efficiency and self-sufficiency of the resulting structure, its anticipated life expectancy, the ease with which materials could be recycled in that event, and so on...
Given all this (and the things I've missed out), but ignoring current fashions, aesthetic considerations and other peripheral matters, what is the 'greenest' building type (for a home), construction method, and combination of building materials there is?
Well, living in a cob house that was originally thatched, it's tempting to agree with you Tony (when asked, i do tell people I live in a mud hut!), but I suspect that discussions about U values would come into the conversation at some point - otherwise, why aren't we all building them now...
Caves? Does anyone remember Mole Manor - a home built into a small disused quarry in th esouth of England in the 1970's? It's been done better since mind...
Do I get the impression that this discussion isn't being taken entirely seriously...?
Anything built from unprocessed raw local materials - if you've got local timber available, great; straw bales, cob, stone, light clay, stone, slate - anything raw and local. For insulation the same would apply, although it's of such importance for the long term energy consumption of the building that you could be less strict and get, say, UK hemp or pressed straw or wool or whatever.
Posted By: SteamyTeaHas anyone looked at the ICE document to find the lowest embodied energy/carbon materials?
Yes, in the Green Building Bible: Volume 2. A more extensive study describing the ethical model used for the GBB study was undertaken afterwards resulting in a technical advice note issued in The Institution of Structural Engineers periodical (May 2008 from memory).
"Not so sure about straw bales, lots of energy used in growing the crops (fertiliser and tractor fuel, change of land use) and in transporting to site."
Straw is a waste material, the crop will be grown anyway, better to use the straw than burn it like thousands of tonnes are every year. (recycling) Yes it is transported to site but every book or web site on this subject suggests that the straw is sourced locally.
I fully intend to use straw for my new build, what could be better or greener than recycling a waste product to give a very well insulated, vapour permiable home. I suggest that this is greener than using lots of man made products to build warm homes. (and I intend to have a wood burning stove to recycle all the waste wood i can).
Posted By: joe90Straw is a waste material, the crop will be grown anyway, better to use the straw than burn it like thousands of tonnes are every year.
Straw works out OK providing you furnish the rest of your property using similar material types. If you don't do this, then straw can work out worse from an embodied point of view.
But embodied isn't as important as your heating system and the type and width of insulation you have chosen. Straw is OK (and cheap) for insulation but for some applications doesn't work out well.
Wasn't being critical of using straw as a material, just that I suspect that there are lower embodied energy materials that one could use. As for local sourcing this is fraught with problems, as everyone 'knows' it is much better to get the local farmer to deliver the veg box than drive to the local supermarket. That will be tested when they all have to put the carbon footprint info on the products. I live in an area that does not produce much straw so rather stuffed there, we don't have many trees either so that is out as well. probably why the housing is granite
Straw works out OK providing you furnish the rest of your property using similar material types. If you don't do this, then straw can work out worse from an embodied point of view.
I am planning to clay and lime render the straw both inside and out (most common way of straw bale build nowadays) and doors and windows in oak. Roof insulation to be re-cycled paper.
With regard "embodied energy" surely using a waste product that would otherwise be burnt (releasing particulants etc) is better as the embodied energy for the plant is set against the original product, i.e. wheat ETC.? and if the house should fail the straw will rot and provide some good nutrition for someones veggies!
Otherwise, It varies depending on what is meant by green
For instance, if green means low embodied and therefore low carbon emissions right now then short term low embodied contents are suitable If green means to reduce carbon emissions to reduce the probability of global warming then low embodied short term or long term high durability but low annualized embodied structures are suitable If green means the above but also to take account of peak oil reducing future generation's access to power, then generally long term structures work; particularly if there is an energy 'crunch' before other power (such as 'world grid' solar' or nuclear is developed
However, we could end up having to revert to agrarian society in which case we will need a knowledge base of short term construction methods.
Green also means other things to other people (such as natural materials)
I can't argue with any previuos suggestions - they are indeed good ones, but I do have a question regarding materials you would use for other aspects of a reno or new building project, like for the framing or things like that. What abour reuse of salvaged building materials? Is there an market in place in the UK? or is that not something that there is excess of? In the US there are used building material ventures popping up all over - which is diverting a lot of waste from landfills here and also provides an alternative to raw material use.
Also, you might need to consider the size and occupancy of your building. I don't think a 15 bedroomed mansion with 10 ensuites - even if it is built out of straw, would be green if you were just a single person. err. am i going off the track again?
people who are serious about green building and sustainability are probabaly aware of this issue, in that they are thinking more about quality in the square footage, not quantity. It is the people who are building green without any actual knowledge of sustainable practices that are doing more harm than good
jkalar , i've used building material reclaimers , a small number have been around for a while , only for specific thing though, eg. Tile , slates , doors ,stone, larger timbers, old cast iron radiators and other fancy stuff which would probably be called architectural salvage
There are some new ones springing up which appear to be trying to supply more along the lines of a standard Merchant keep thinking about starting one up , have been for a good few years It would be good to link it with a skip/rag and bone service as the material source Got garages and shed loads of stuff I just cant throw away perhaps I should just upscale the operation from junk to collector to junk baron
That is what i have found in researching this topic as of late, a lot is still architectural salvage and antique salvage - which is better than nothing, i guess. But there is a lot more that can be saved when a building is to be torn down than just crown moulding. Here people are being trained to remove fixtures to floorboards, all the way down to the framing if it can be saved. certainly the greenest thing in my opinion
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