I have a three storey Victorian terraced house. The upper attic rooms had already been converted, but I think that there is little or no insulation between the ceiling which follows the angle of the roof and the roof itself. It gets very cold up there in Winter and very hot in Summer. Is it a reasonable thing to do to put battens, insulation and a lower ceiling in if height allows, or should I take down the ceiling and start again. I am also thinking of the hassle with dirt, dust and whatever. What thickness and type of insulation should I use bearing in mind that I do not want to lose too much height. Any help gratefully received.