Eduardo Ferraz of the Polytechnic Institute of Tomar in Portugal said that bricks are often impregnated with polystyrene, as this way they enhance their heat-trapping abilities.
This bricks remain strong this way and can be used to build energy-efficient buildings, New Scientist reported.
However, restrictions imposed by the EU on the release of carbon emissions have made it expensive to include polystyrene and other similar synthetic materials into bricks.
With a clay paste containing 5 percent spent grains, Ferraz and his colleagues were able to create bricks, which were just as strong as the conventional kind of bricks, while reducing the amount of heat they lost by 28 percent.
The team said that the reason for this is that bricks become more porous from the grains and thus they trap more air, which in turn increases heat retention.