Conditioning and Ventilating an Attic
Hi all, I’m a new home owner in Sarasota. I’d like your advice on conditioning my attic and upgrading the ventilation. I’ll list some particulars about my current situation, and then the order of steps I’m thinking to fix it, but I’m no expert. If anyone knows a contractor I could hire to execute this for me, please let me know.
– Home: 1,500sqft concrete block home in Sarasota.
– Roof: 3/12 pitched shingle roof covers most of home, but I also have a flat bitumen roof that covers the master bedroom, lanai (screened-in outdoor area), and part of garage (not conditioned). Both roofs due to be replaced.
– Attic: vented with blown-in insulation on the attic floor, put in 2010. Plumbing and venting goes through this space, which is insanely hot in summer. I hear rodents from time to time running around up there.
– HVAC: a 3 ton 14 seer 36,000 BTU single-stage heat pump (installed Oct. 2020). Package unit outside of house. I use a portable 50-pint dehumidifier.
My rough plan to condition attic and increase comfort:
Step 1: Roof: replace the pitched roof with a 24 gauge striated standing seem roof. Replace the flat roof with a GAF Polyiso Taper System, 60 Millimeter TPO. I tried to talk to a couple roofing companies about adding insulation to the pitched roof, but none of them do that. It’d be a challenge (impossible?) to try and coordinate a roofing & and insulation company in this area right now.
Step 2: Insulate pitched roof directly underneath roof sheathing. Remove the blown-insulation first. Then, use aero-barrier to air seal the attic. After that, my preference would be to install mineral wool BATs against the roof sheathing, but all the companies I talk to steer me to open-cell spray foam. They look at me like I’m crazy when I suggest closed-cell. I’m concerned about dealing with leaks with a spray-foamed roof.
Step 3: commission a Zehnder ERV along with whole-house dehumidifier (like Matt Risinger did).
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