Sat, 18 Apr 2026 12:34:43 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18286#Comment_18286 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18286#Comment_18286 Thu, 10 Apr 2008 15:14:16 +0100 Mike George
No sitting on the fence please, Answers are:

Always
Sometimes
Never]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18287#Comment_18287 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18287#Comment_18287 Thu, 10 Apr 2008 15:15:44 +0100 Gervase Webb https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18291#Comment_18291 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18291#Comment_18291 Thu, 10 Apr 2008 16:14:13 +0100 Chris Wardle
I'd like to see more use of less energy hungry alternatives where possible. For example, compressed earth blocks or hemp lime blocks instead of concrete blocks in buildings, and less energy intensive types of cement. Failing that, more sparing use of OPC, for example in foundations which often seem over the top to me.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18301#Comment_18301 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18301#Comment_18301 Thu, 10 Apr 2008 17:41:18 +0100 jamesingram so I guess always
I'd love a alternative to be in common use , but I feel at the mercy of designers,engineers and building controls
Anybody know much about mirco piles as a OPC free footing ,
Until I can find customer happy to pay for the preferred alternatives , theres no choice]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18309#Comment_18309 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18309#Comment_18309 Thu, 10 Apr 2008 18:52:10 +0100 jon
OPC is a high energy product with some high value characteristics. If we need high value characteristic materials for a building but do not wish to use OPC (or steel, aluminium or other high energy products) the solution may be to change the design requirements rather than to look for ways not to use the materials that are best suited to that design.

Micro piles are usually OPC James unless Mirco is a tradename or you mean the small screw steel type.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18319#Comment_18319 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18319#Comment_18319 Thu, 10 Apr 2008 19:40:57 +0100 Chris Wardle https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18321#Comment_18321 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18321#Comment_18321 Thu, 10 Apr 2008 20:17:34 +0100 jamesingram I ment the small screw steel ones you mentioned, i know nothing about them, but they seem a good alternative to
trench fill/traditional footings
Strip foundations a good idea, to reduce trench fill , but on deeper work it a bit tricky
the footing mentioned above was 1.8m deep , 800 deep trench fill , block up to dpc
and the brickies still moaning that I didnt fill it higher

cheers Jim]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18325#Comment_18325 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18325#Comment_18325 Thu, 10 Apr 2008 20:59:18 +0100 jon
Also bear in mind that the NHBC guidelines are quite specific about the uses and minimum depths: The regs are safety driven whereas the NHBC is more insurance driven meaning strips can sometimes only be used in cases where no insurance is required.

A low embodied alternative for low level housing units, if you can be bothered, is to dig in small segments down to good bearing strata, use the maximum stress allowable at that level. bring up the (lightly OPC'd) hole up to ground level and then use PC units as your 'foundations' off which to spring everything else: Works out at about 1/3 the CO2 content typically (I have used it as an option in some level 5 proposals).

jon]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18328#Comment_18328 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18328#Comment_18328 Thu, 10 Apr 2008 21:26:30 +0100 chipedwood
I say it is always acceptable to use it.

It's a very good material but I do think that it should be used more carefully than it is.

Like in this flat, a concrete floor was put in upstairs replacing a wooden one when it became rotten. That I consider stupid and should't have been done.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18337#Comment_18337 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18337#Comment_18337 Thu, 10 Apr 2008 23:37:46 +0100 biffvernon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18342#Comment_18342 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=18342#Comment_18342 Fri, 11 Apr 2008 08:26:17 +0100 TheDoctor
Effective public transport RELIES on population density.

Density RELIES on an element of high rise to maintain green spaces in the population centres

there are also huge economies of scale in materials, energy consumption etc in population density.

spreading everyone out to their hypothetical 1 acre per person of the UK land mass would be a disaster

OPC is a part of that density solution, although its use could be limited and more carefully considered]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20383#Comment_20383 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20383#Comment_20383 Sat, 10 May 2008 21:47:38 +0100 tipper https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20384#Comment_20384 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20384#Comment_20384 Sat, 10 May 2008 21:59:49 +0100 Mike George https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20487#Comment_20487 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20487#Comment_20487 Mon, 12 May 2008 18:23:37 +0100 Dominic Cooney https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20498#Comment_20498 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=20498#Comment_20498 Mon, 12 May 2008 20:21:27 +0100 biffvernon
(That is such a small proportion of current usage it appoximates to 'never' for the purposes of my vote at the top of this thread.)]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21770#Comment_21770 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21770#Comment_21770 Sun, 25 May 2008 19:49:24 +0100 Dr T https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21782#Comment_21782 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21782#Comment_21782 Sun, 25 May 2008 21:17:06 +0100 paul.dixon27 for myself, I do use it sometimes, in small quantities.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21786#Comment_21786 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21786#Comment_21786 Sun, 25 May 2008 21:44:07 +0100 biffvernon Posted By: paul.dixon27 OPC reabsorbs CO2 from when it commences setting, as does lime, No, very little of the CO2 is reabsorbed by OPC as it sets, while all of the CO2 is reabsorbed when lime sets. The reaction calcium carbonate to calcium oxide to calcium hydroxide to calcium carbonate is known as the 'lime cycle' and has no net production of CO2 once the cycle is complete (other than from the fuel used, of course, which as we have seen is less in lime making than OPC making). When cement sets there is very little reabsorption of CO2 from the atmosphere as it is the silicates from the baked clays that do most of the action.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21796#Comment_21796 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21796#Comment_21796 Sun, 25 May 2008 23:32:08 +0100 Mike George https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21801#Comment_21801 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21801#Comment_21801 Mon, 26 May 2008 01:44:51 +0100 paul.dixon27 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21809#Comment_21809 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21809#Comment_21809 Mon, 26 May 2008 08:43:28 +0100 biffvernon https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21826#Comment_21826 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21826#Comment_21826 Mon, 26 May 2008 13:36:13 +0100 Rachel Re concrete CAT records show that 40% or the worlds energy goes on making concrete and I heard it is around 7% with lime, altho lime is continously carbonating over years and years.. go go lime...]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21829#Comment_21829 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21829#Comment_21829 Mon, 26 May 2008 13:49:33 +0100 Mike George
Don't get me wrong, I have nothing against lime. But I would like to know just how green it is in production . If concrete is such a bad boy I would like to know just how bad]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21831#Comment_21831 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21831#Comment_21831 Mon, 26 May 2008 14:21:13 +0100 biffvernon http://www.singletonbirch.co.uk/ get in touch with them. They have a very helpful techie department.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21832#Comment_21832 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21832#Comment_21832 Mon, 26 May 2008 14:23:19 +0100 Paul in Montreal Posted By: RachelRe concrete CAT records show that 40% or the worlds energy goes on making concrete

Nonesense.

From http://www.buildinggreen.com/auth/article.cfm?fileName=020201b.xml

"In the United States, producing the roughly 80 million tons of cement used in 1992 required about .5 quadrillion Btus or quads (1 quad = 10 15 Btus). This is roughly .6% of total U.S. energy use"

You're off by almost two orders of magnitude. Perhaps you're thinking CO2 emissions? 36% of total CO2 emission come from industrial processes of which cement is a large contributor - but it comes out closer to 10% of the world total. So you're still off by a factor of four.

Paul in Montreal.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21834#Comment_21834 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21834#Comment_21834 Mon, 26 May 2008 14:54:15 +0100 Mike George Posted By: biffvernonMike, I had a tour round Singleton Birch's limeworks a little while ago. If you can't find the data you want on their website:http://www.singletonbirch.co.uk/" rel="nofollow" >http://www.singletonbirch.co.uk/get in touch with them. They have a very helpful techie department.

I was hoping that those who say OPC should never be used would be able to come up with some figures which justify their stance - perhaps the figures do not make happy reading? Are you in denial? ]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21837#Comment_21837 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21837#Comment_21837 Mon, 26 May 2008 15:32:45 +0100 Mike George https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21841#Comment_21841 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21841#Comment_21841 Mon, 26 May 2008 16:08:47 +0100 ted
http://www.buildingforafuture.co.uk/autumn05/ordinary_portland_cement.pdf]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21842#Comment_21842 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21842#Comment_21842 Mon, 26 May 2008 16:15:54 +0100 ted
http://www.wbcsdcement.org/research.asp

If you are short of free time then Reports 6 and 8 are the main ones.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21849#Comment_21849 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=1554&Focus=21849#Comment_21849 Mon, 26 May 2008 17:14:28 +0100 Mike George
'some hydraulic limes are capable of reabsorbing nearly all of the CO2 released in their formulation, but this figure does not account for the C02 released in the kiln which can be on a par with cement'

Not really clear that!

It makes no comment of energy used in transportation.

The other reports do not appear to draw comparisons with lime, though I have only scanned the two you note.]]>