Porch roof

This is my first post so please go easy on me !!!

I am having an open porch constructed at the moment. It will be roofed with T&G over the top of the spars followed by rosemary clay tiles (this is to match the style of the main roof which has open eves with T&G boarding over the eves.

My question is and may be stupid but do I really need breathable roofing felt under the tiles. Surely I don't need this in an open porch???

Thanks for any help you can offer

cant see that it will make much difference what you use for an open porch.

Thanks for the quick reply - that's what I thought - I figured it should be pretty well venitlated as it's fully open !!!!