Brian Knight wrote:The beauty of Permaculture is that there are so many ways of doing things! I dont see anything incorrect about using steel. Its often the only choice in necessary components with heavy green roofs. A better permies practice would involve sourcing some pre-used beams.
I wouldn't bet on it. It might work if you had a loose layer above the tiles for water to drain away in (gravel or another layer of tiles laid on top of the official ones), but earth in contact with the tiles would wick damp through to the inside even if the joints were all perfectly grouted. (Unless you could fire the tiles to stoneware... very unlikely.) I think rubber/plastic will be the most effective and by far the easiest method for waterproofing.
I was wondering if a properly grouted roof in this style could be made watertight in such a way that it would stay that way under the WOFATI roof. I know if you tried that with any traditional shingle, the saturated material sitting on top of the roof would allow water to wick up between the tiles and eventually inside.