Roof with Shallow Pitch Information, help and advice on maintaining, installing and repairing a flat roof. Post your questions and view answers here

[DaveC]

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.

Thanks

[biggles111]

If you are worried about the holes made by nailing on the batten causing a failure in the underlying felt/vapour barrier, why not put a second layer of underfelt over your slate battens before laying the slate.
I think that the slate if layed in the propper manner combined with the additional under felt will give a safe watertight barrier - especially as you intend to build a propper flat roof below it . Unusual construction but should be workable .

[DaveC]

Thanks for the advice