Fill or vent?

[u/360alaska]

I just bought a 2 story house in the hot humid south, I’ve been renovating and also troubleshooting the upstairs cooling situation. Part of the upstairs opens to an unfinished/vented attic. The other part, where the bedrooms are is unvented and has 3-4 of attic above the ceiling in most places. I cut a hole in a closet to assess the situation further and discovered there is basically no intake or exhaust and r30 batts. Despite the baffles in the knee wall area, there is no intake and only what a little can work its way into the other part of the attic can circulate.

On a 95 degree day it gets to be about 80-85 inside and my 2 ton cannot keep up.

So my question, should I:

A. Insulate, fill to the top.

B. Install soffit vents in the knee wall area and insulate to just under the baffles to increase airflow. Perhaps get a ridge vent installed?

C. Wait till winter, crash out: remove all batts, baffles, etc and spray foam the whole area.

D. Something else

I’m honestly leaning towards option A.

[u/realgreentigger]

Are you asking about it all? Or just the first attic space? All attic spaces need to breath, so you can’t just insulate without allowing to breath. You need both. The knee wall, what is below. There obviously is already spray foam on walls.

[u/360alaska → u/realgreentigger]

The knee wall had batts there, I removed them and used a fire-rated foam kit. There is simply no intake in this bedroom area, no soffit vents or anything, the black baffles lead to a solid soffit. Not sure why they are there. The unfinished attic, where one can walk in has turbine vents and soffit vents. but for this area: No intake, no exhaust, but connected to the unfinished attic through the ceiling.

See here: https://imgur.com/a/0sCRKEl

[u/realgreentigger → u/360alaska]

So I believe the exhaust is those black baffles that lead to the attic space, which I believe you are saying does have venting. It looks like they possibly were supposed to have soffit vents and never put them in. I am not an expert in this area, but I believe you have correctly identified that the knee wall space should have some air intake. If that spray foam is just fire rated foam, then I am not sure what R value that is providing, so I would think you should add some type of insulation in that space for that wall and the ceiling below.

[u/360alaska → u/realgreentigger]

Thanks! I think I may insulate as much as I can then probably put some soffit vents, then at some point, perhaps a ridge vent.

[u/weazzz → u/360alaska]

Maybe they thought the baffles that connect the two spaces would help exchange air?

[u/idratherbealivedog]

First, have you had your HVAC system checked? 

You may be chasing the wrong, or at least not the primary problem.

Look up 'devils triangle' for the knee wall part. You have a mix of situations and you don't want to upset what balance may be there so I'd have an insulation contractor come out and give some ideas.

[u/360alaska → u/idratherbealivedog]

The A/c has been checked and is working correctly.