Anyone know of the correct way to do a sod covered roof? I was thinking of laying down 2x6 flat across the purlins, with the span between the purlins and cap logs/ridge pole being only 3'. So they should be able to handle the log over the 3 foot span, even laying flat. Then, apply a waterproof covering (spar varnish, water seal), then a 45 mil plastic pond liner. On top of that, of course, moss, lichens, etc.
Any thoughts on this?