I want to construct a roof with a pitch of 12.5deg and a slate finish.
I am considering a flat roof constrcution,ie ply, then felt or breathable membrane, followed by counter-battens nailed along line of rafters, then battens and slate? This would be similar to several roof constructions in our area (with the slates being cosmetic rather than functional). However, I'm not sure about fixing the counter-battens as it would involve compromising the integrity of the felt or membrane.
The roof is for a single story kitchen extension.
I would be grateful to hear from anyone who can offer advice or who has experience with a similar construction.