Update Roof Ventilation ?

No signs of mildew or musty smell in the attic.  Honestly, it's been "fine" all these years.  This area of the attic storage space sits on top of the dining room, which has old MR16 lights on the ceiling and I can see light here and there when looking down...so there is opportunity to air seal this space inside the attic. 

I would think a dormer installed here, would just pull (albeit, lightly) conditioned air through these small crevices through the attic and out the vent. 

I get where you’re coming from, but I’d be a little cautious about relying on those old MR16 light gaps for “ventilation.” Sure, you haven’t had mildew yet, but all it takes is one gnarly storm or a humid summer to tip things the wrong way. I’ve seen attics that were “fine” for decades suddenly start sweating after a minor roof tweak. If you’re thinking dormer, I’d seriously consider proper air sealing first—otherwise you might just be sucking your cooled air straight out. That’s like giving your AC a gym membership it never asked for...

That’s a good callout. I’ve seen people trust those old fixture gaps, but they’re really not designed for actual airflow. If you’re updating the roof or adding a dormer, proper vents (like ridge or soffit) make a noticeable difference. Air sealing’s huge too—otherwise, you’ll just be cooling the outdoors. Learned that the hard way in one of my rentals... utility bills shot up before we fixed the leaks.

I think if I just leave it alone and not add the dormer, I would be better off.  Eventually, I will replace those MR16 lights and air seal around them. 

Not adding the dormer does keep things simpler, especially if you’re already thinking about air sealing and swapping out those MR16s. I’ve gone down a similar path—kept the roofline as-is, focused on tightening up the attic envelope, and honestly, it made a noticeable difference in both comfort and utility bills. Air sealing around recessed lights can be a bit of a pain, but it’s worth the effort if you’re already poking around up there.

One thing that came up for me when I was doing this: how’s your current attic ventilation setup? I had a mix of old gable vents and some questionable soffit vents that were half-blocked by insulation. It turned out the airflow wasn’t great, which led to some minor mold issues near the eaves after a wet winter. Ended up adding continuous soffit vents and a ridge vent, which balanced things out pretty well.

If you’re not adding a dormer (which can sometimes help with venting), have you checked whether your intake and exhaust are balanced? Sometimes folks just have a couple box vents up top and think they’re set, but without enough intake at the eaves, it doesn’t really work as intended. Also, if you’re air sealing around those lights, just make sure you’re not accidentally blocking any vent paths—seen that happen before and it can cause more headaches down the line.

Curious what kind of roof you’ve got—shingles, metal, something else? And how old is it? Sometimes the age or type can affect what makes sense for ventilation upgrades.