An exhibitor at the Listed Property Show was selling new reproduction cement pattern tiles of the 1930s onwards and commonly found in France, Italy, Portugal and Spain where tiled floors helped keep houses and workplaces cooler in the summer. The same exhibitor was also selling antique pattern tiles.
 
The new tiles are made from white Portland cement with the patterns inlaid using metallic oxides added into the cement mix. It takes a lot of energy, from fossil fuels, to manufacture ordinary Portland cement, and even more energy to make white cement. Cement is one of the biggest causes of global warming. It is estimated that around 5 per cent of global warming is caused by cement and concrete.
 
Once the tile is made it embodies the amount of carbon needed to make it. The carbon is emitted to the atmosphere in the form of carbon dioxide. A 20cm square cement pattern tile 2cm thick weighs 1.8kg and embodies 20MJ of energy which emits 2.7kgCO2e. A newly-planted tree with a 100 year life will sequester 2.7kgCO2 in around 9 months.
 
A floor 6m by 6m square laid with 450 new 20cm pattern tiles has an embodied energy of 8,100MJ and embodied CO2 of 1,215kgCO2e. This is equivalent to 528 litres of petrol or diesel, or 20 refills for a small family car, and 5,500 miles travelled. It is equivalent to the carbon captured by a 500 trees in a year.
 
When reclaimed pattern tiles are used for the 6m floor 1,215kg of CO2 would be saved.
 
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kgCO2e stands for kilograms of carbon dioxide equivalent to the mix of greenhouse gases produced by the energy, such as methane and nitrous oxide. The figures for carbon dioxide sequestered by trees come from the UK Government's 'Woodland Carbon Code'. The figure for the embodied energy of white Portland cement seemed to not be available, so it was estimated by Salvo, based on the embodied energy of ordinary Portland cement and available technical information about the difference in how white cement is made.