Hi,

I'm currently rebuilding a cantilevered porch (10' x 8' approx.) on the front side of my house that was more or less previously destroyed by water damage (poor waterproofing on the top of the deck). I've put tons of work into pulling up flooring / subfloor inside the house to reinstall new joists for the porch, etc.

I'm getting down to the final sequencing of the porch rebuild, including fascia install, flooring / waterproof membrane (EDPM + deck tile), railing, ceiling beneath, etc. Without going into all the details and project sequencing, I'm struggling to understand if / and when my ceiling below needs to "vented". As of this moment, I was planning to install a beadboard ceiling for the entire length of the porch, which the corbels will "reconnect" to. There should be no water getting into the rafter area from above due to the waterproof membrane. In theory... humidity changes could result in moisture getting up there... or something? This is where my knowledge / understanding runs out.

If I DO need to vent, I would need to vent every bay, correct? If so, there are technically 12 (7 joists = 6 bays, middle blocking 2x = 12 bays). I'm struggling with how I would accomplish this without having a somewhat ugly ceiling / etc. - I thought about cirular soffit vents on the beadboard - a couple would look okay but 12 seems obnoxious.

Another brief question: I'm currently planning to install fascia with a j-channel that would extend 3/4" below the joists / framing to carry beadboard / the ceiling (which my sequencing will lead to my EDPM next, drip edge, etc.). If you think this decision is independent of my ceiling venting issue, that would probably help me keep things moving without getting too hung up on this... thanks...

New porch:

Old porch: