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Can you help me scope this insulation project?

awinn17 | Posted in General Questions on

My house is 1.5 story cape style, Kanawha County, WV (Zone 4 near 5. House just scored 10.89 ACH50 (yay me!) I am currently air damming the knee attics (maintaining vent baffles), sealing outlets, can lights to drywall, plumbing, etc.

BUT THE ATTIC has several competing problems, mainly evidence of thermal leaks (spotted snow melt spots). HVAC is in the attic, R4 flex duct, etc. Obviously a major big heat loss area, with evidence to link it. So I think I want to spray foam the main upper attic at a minimum to get the HVAC in the thermal boundary & air seal the upper boundary at the same time.

I see a few options…

Option A- spray foam just the main attic, ridge vent to attic plate. Continue vent baffles to ridge vent, and spray foam the rafters. This would ensure soffit ventilation air flow is maintained through the rafters that are not spray foamed. Not sprayed would be main vaulted ceilings, dormer attics, short sloped ceilings in rooms upstairs, and knee attic rafters.

This is my main question… IS THAT OK? Am I creating any condensation/humidity/airflow problems? I know to condition the attic space after it’s sealed. But that amount of contractor work may be all I can justify before the work gets cost-prohibitively and “life-impactingly” (i.e. my wife would kill me for destroying the house) expensive.

1) Dormer attics. Accesses from main attic are too small for a person. Can I close them off and foam over? Should it be covered with cellulose first? Is Does a ridge vent get installed over the dormer ridge? Soffit vents? (They may be vented now but I’m away and can’t check).

2) Long vaulted ceiling. It would maintain its soffit ventilation baffles to the ridge vent. I thinkĀ I’m ok doing that… am I missing anything?

Option B- This is just option A + the accessible knee attics and use an extension wand spray the sloped ceiling between knee attic and main attic. I think I could/would justify the added cost since this is all still accessible by the foam installer. This still excludes I think 5 “cubby spaces” in the house that are boxed in, and a large vaulted ceiling.

Option C- This is Option A + B + demo (or you tell me what’s better) the vaulted ceiling drywall, cut accesses to the 5 cubby spaces, demo dormer ceilings for access, demo ALL vent baffles (convert entire house to “hot roof”), spray foam continuously from soffit to ridge, reinstall drywall, live in debt to my wife to eternity but bask in the approval of the energy diet(ies). I can just smell the smoke from the money burning but I wanted to present it as an option I believe to be “the most ideal”.

Last question… they all push open cell but then tell me they’d install to like R24… Seems like not enough… R38 I think is minimum current code in my area, so how do they get away with that? How do we all feel about open cell vs closed…? Closed cell cost is very high and makes me nervous not being able to spot a roof leak (I do have solar, so like 200 more holes in my roof to worry about).

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