It's Rastra, mon, not Rasta!
Put on the Bob Marley while we tell you a tale about Rastra- an ICF (insulated concrete form) that is "a sustainable, energy efficient, environmentally correct construction system". Lets get it out of the way first to say that as an architect, we have not been fond of ICF's because one cannot be certain that trades have properly filled the voids; as a treehugger we thought that polystyrene and concrete were not the most appropriate sustainable materials. Then we learned about Rastra- Its made from recyled material and uses a lot less concrete than other ICF's we have seen.Rastra blocks go together like pieces of Lego, and can be shaped into curves, free form layouts, and appear to be much more flexible than most of the ICF's we have seen. It needs plaster on the inside, stucco on the outside and it is done.
In a recent article on a Rastra house we read how gin bottles were placed in walls for light (we are saving our Bombay Sapphire glass blocks starting today) and how the material lets a builder be whimsical and different.
So lets not be doctrinaire- The thermal mass of the concrete makes for a cooler house in the day, warmer at night; there is a lot of insulation; its fireproof so when you drop your ganja you will be fine in the morning; it will last for generations. Perhaps we should rethink our objections.