Hi, wondering if anyone had any thought on this... I'm currently building a 7m x 4m workshop in my garden with a single layer of concrete block walls with 2 pillars on each wall. I"m considering the idea of having a turf roof (based on the instructions at www.cat.org.uk/catpubs/tipsheet.tmpl?sku=17 ). My dilemma is if the single block wall and the 18" deep foundations will be happily support the weight of the roof which the site suggests will be about 500kg per square metre - any thoughts?? Also does anyone have any idea if a grassed roof will need any pitch on it - with the depth of the grassed roof being about 400mm, I'm concerned that if the roof has to be pitched much the building height will rise to above 3 metres, and won't be exempt from building regs approval. Any help would be appreciated.