Hi all, Im just thinking about putting the lid on my smoker which is a brick shaft about 660mm wide by 1350mm long. I was going to use concrete but I'd have to cast this on the ground and lift it into place and if i do it at 100mm thick for that size its going to weight an absolute ton. Plus the walls are only single skin brick and I'm a bit worried about the weight. Does anyone have any other suggestions? Does the roof need to have a lot of thermal mass to keep the heat contained or could I get away with a large piece of cement board? Thanks in advance for any help. Leoric.