Southern PA/DE - Attic Insulation
Hi, I live in southern PA [zone4] and I am having problems cooling my house [built in 2008]. After a lot of research, I'm looking to prioritize my next insulation steps. But I am unsure of the best way to proceed.
1) Above 3 car Garage - Unfinished, Uninsulated, Non-living room (approx size of bedroom with exposed roofing)
2) Redo duct work and insulate ducts + sheath the return lines which are just in between drywall and 2x4's right now.
3) Attempt to insulate the rest of my attic which is pitched, but contains much smaller spaces above the other 2nd floor rooms (approx. 3ft gaps - unknown insulation level)
4) Find the highest spot in roof (approx 150F) and install solar powered fan?
5) Redo rift vents (bigger?)
6)What type of insulation is best for my shallow roofing above 2nd floor rooms (recommended R-38 +)? What is the best way to seal the 2 attic entrances? (pink styrofoam stuff - silicone glue - plywood door?)
My current guess:
Thanks for all help. I can post pictures / dimensions if needed.
Pictures are helpful in cases like this.
Get on Building Science.com and start researching.
They have a pdf and answer for every question you have.
In a nutshell...
Thanks. The PDF diagrams on the BuildingScience website help a ton.
Ok I think i've got my air seal design down.
Where do you recommend buying foam board, insulation blower, radiation barrier, and soffit vents? Right now, it seems like my most reasonable bet is with Home Depot.
I hate to pester, but I came across another potential problem while examining my existing soffit vents.
It appears the standard soffit vents I have installed and the ones I can buy at home depot have about 15% of their sq. ft space ventilated. The other 85% could be considered solid plastic. Taking this into account there is no way I have the 1 sq. ft. per 300 sq. ft. of ventilation area that is recommended. Also, I have yet to see a good mesh/screen type design. Most designs are plastic with raised and slightly covered holes leaving little true ventilation area.
1) How hard is it to replace soffit vents and what do you guys recommend to keep bugs out but still ventilate well?
2) Is there another way to check for adequate attic ventilation other than measuring soffit and or ridge line ventilation area (perhaps an air speed sensor or temp recomendation etc)?
Home Depot/Lowes are fine for the foam board.
I would not use their cellulose for blown in work (they carry the cheaper stuff that is ammonium sulfate stabilized vs. the borate only stuff (a bit more premium but far better = no off gassing).
Soffit vents are fine. I am not sure what route you are going on this though.
The better soffits are available via building supply houses and the Alside Charter Oak soffit is my favorite.
Most of the soffit vents (single units) have a screen mesh to them, but if you use a fully vented vinyl soffit, you the bugs don't go up there much and not if you have borate stabilized cellulose.
No way to cheaply measure air flow that I know of. Make sure the system is balanced and you will be fine.
Once you air seal and insulate, you somewhat reduce the necessity for venting (you don't eliminate it or even approach that, however, reducing the air leakage into the attic reduces moisture considerably).
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