The concrete industry has been unfairly characterised in recent years as a ‘culprit’ in the environmental equation. This characterisation is a misrepresentation of the true environmental performance of concrete which has many credible environmental credentials. Environmental performance is of course ‘relative’ and substituting one construction material for another is a viable proposition if one material is more friendly to the environment than another. However, to date, the Irish Concrete Federation have not unearthed any scientifically based independent study, in Ireland or abroad which suggests that substitution of concrete with timber or steel is of benefit to the environment. On the contrary, recent figures produced by an independent group of leading 1Irish consultants show that one tonne of softwood contains 10 times the embodied energy and 8 times the embodied CO2 as one tonne of structural concrete. Comparing concrete to steel, steel consumes 30 times the amount of energy in its production than concrete for the same mass of product. These figures are substantiated by 2independent studies abroad and would not suggest timber or steel is better for the environment than concrete.
Generally speaking, the contribution of concrete to social and economic development is not disputed by ‘environmentalists’. It is well understood that concrete is crucial for the development of dams, fresh water supplies, roads bridges, sanitation, tunnels and transportation and all types of civil engineering and construction projects. In many construction projects there are few if any viable alternatives to concrete.
Highlighting concrete’s ‘sustainability credentials’ is far from overstating its importance. It is not an exaggeration to say that the development of concrete in all its forms has accelerated the rise of modern civilisation and civic society. However, even such an outstanding contribution to civilisation would be open to question or re-evaluation if concrete had a poor environmental performance. However, concrete’s environmental performance is comparable with alternatives and in the Irish context it is arguably superior to alternatives.

There is no scientific environmental basis for substituting concrete with other materials
One of the problems in discussing environmental performance is that 3‘yellow pack science’ is widespread. This has its origins in marketing - with material ‘substitution’ as the end goal. Most ‘studies’ are industry sponsored and tend to come up with the result favourable to the sponsor. These studies tend to be ‘non holistic’ , as for example studies which take into account the ‘construction phase’ only and completely disregard the ‘in use’ phase which accounts for almost 90% of the environmental impact and where it is well documented that concrete has a distinct advantage because of ‘thermal mass’.
Likewise comparisons are made between construction materials which include recycling or burning for one material, but which leave out recycling for materials such as concrete which are in fact 100% recyclable.
The fact that there are problems in making comparative performance assessments does not mean that science has no say in the matter. So long as studies are ‘independent’ and that the ‘object’ and ‘methodology’ of the study is clearly defined, then studies can come up with conclusive results. Also, ‘Life Cycle Analysis (LCA) which includes ‘cradle to grave’ assessment of materials and constructions is essential. Such studies show that concrete is at least the match of substitute materials such as timber or steel in terms of environmental performance.

Chalmers University Independent Study Produces Conclusive Results
A comprehensive study, representing an assessment of 8 full life cycle analysis studies (6 of which were independent) was concluded recently in Chalmers University, Gottenburg, Sweden. The assessment compiled and assessed the substantial body of knowledge on the relative environmental impacts of concrete, timber & steel house constructions which had been gathered in the Institute of Environmental analysis at Chalmers over a number of years. The study which was entitled ‘What does an increase in building with wood materials mean in Sweden for the environment’ was carried out by Birgit Brunklaus and Dr. Henrikke Bauman and was commissioned by the Christina Leidman in the Swedish Department of the Environment. The study concluded that ‘Wood is not a better or worse environmental alternative seen over the complete life cycle of the houses’. A translation of the report is available from the Irish Concrete Federation on request.
This conclusion is enormous in its implications and had the immediate effect of silencing the anti-concrete lobby in Sweden, from where many of the Irish anti-concrete slogans emanate. The report is all the more credible in that it comes from a university source, located in Sweden – arguably the home of European timber and coincidentally the source of nearly all of the structural softwood which is used in the construction of timber frame homes in Ireland. The result also begs the question as to why various government agencies in Ireland have given credence to the proposition that substitution of concrete by other materials is ‘the environmental’ way forward. It is imperative that the lack of impartiality in such bodies be brought to an end immediately.

Thermal Performance
The relative thermal performance of concrete, timber and steel framed houses has been deliberately confused by marketeers. This confusion has been added to by professional ‘experts’, some of whom have made false and misleading statements from environmental platforms. Once again this topic must be put on a scientific basis. Lightweight framed structures and heavyweight concrete structures have different thermal characteristics. Lightweight structures heat up quickly and this leads many people to believe that they are ‘warmer’. In fact, they also cool down quickly - more quickly than concrete structures which act as a heat reservoir, absorbing heat and returning it to the environment over a period of hours. This storage capacity is a product of concretes ‘thermal mass’ and it produces a ‘thermal bonus’ in that it can store heat from the suns rays which enters through windows and returns the heat over a period of 6 hours, reducing heating requirements.
A recent study carried out by the concrete industry at European level, in preparation for input into the EU Environmental Performance of Buildings Directive (EPBD), assessed model buildings for thermal performance using dynamic thermal modeling and inputting actual meteorological data from the north pole to the equator. Two separate thermal software packages gave virtually identical results, showing that on average concrete structures have a 5% thermal advantage in house construction and up to 20% advantage in office type buildings. These results are simply a scientific verification of what is already a well documented phenomenon. A detailed account of the considerable energy savings to be made by harnessing concrete’s ‘thermal mass’ is given by leading architect Merritt Bucholz in an article entitled ‘Concrete & Sustainability’ in the April/May edition of ‘Concrete Today’ Magazine.

Concrete’s advantages in the Irish Context
Concrete has other advantages in the Irish context. Unlike other construction materials which are imported from countries up to 3,000 miles away and which incur a high CO2 ‘transport tariff’, concrete is manufactured and delivered in Ireland within a 30 mile radius. Also, since Ireland has only very moderate winter / summer temperature swings - typically, 0°C to 28°C – it is practical to avoid the use of air conditioning by using concrete’s thermal mass. This absence of temperature extremes combined with the use of thermal mass results in huge savings, particularly since ‘cooling’ is three times more costly than heating and cooling and not heating is the main environmental cost factor in office/civic type buildings.
Recent figures produced by the EPA as part of the inventory calculation for emissions trading, indicate that the manufacture of cement accounts for approximately 4% of CO2 production in Ireland. This is a modest figure, given that the consumption of cement in Ireland has almost doubled in the last 5 years to the current consumption level of 10 million tonnes per annum. On a world scale, the production of concrete accounts for approximately 7% of anthroprogenic (man made) Carbon Dioxide. These figures are best evaluated in the context of the usage of concrete, which worldwide, accounts for approximately twice the volume of all other construction materials added together. In fact, concrete’s contribution to world wide Carbon Dioxide production is a product of the volume of concrete used and not of the ‘high level of carbon dioxide in concrete’ as some ‘environmentalists’ perceive. It should also be remembered, that unlike fossil fuels which turn to gasses during combustion, the main constituents of concrete do not change form and can be harnessed for use by future generations.