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Roofing/Baffle or no baffle

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Attic
Attic  
Hello Bruce,

When my wife and I bought the house, our house inspector told us we need more insulation in our attic, especially in Chicago! So we went ahead and bought bags of CertainTeed insulation ourselves, as well as baffles after reading much about ventilations.

When I was finally up in our attic, I couldn't see to find the seam where air is suppposed to flow from outside soffit. I saw that the horizontal beam is stuck to the roof boards (red lines), leaving me no room to add my baffles.

I also realize that there were missing insulation material near the edge of the ceiling, as you can see, it's like empty drawers (yellow lines).

I'm not sure if it's intentional by previous owner(s)/builder so that outside air (if any) can penetrate via the edges up to the roof?

I'm confused as to where, if at all, I should be putting my baffles at, like tight against the red lines and fill my insulation covering the red lines?

Or I should leave the yellow boxes alone, forget about installing the baffles, leave a foot of empty area (as-is) and top-up the existing insulation?

Thank you so much for reading my question.

Answer
Nick,

Thank you for the photo and the time you spent describing your condition!

From the outside of your home, if there are no vent holes or screens or open blocking at all where your soffit overhang meets the exterior wall then you home was constructed with no intent to ventilate the attic from there.  You can either install soffit venting by modifying the soffit blocking (wood lying flat between the red and blue lines)which then would require the use of your baffles.  The baffles would be installed between the rafters oriented to prevent insulation from obstructing the screened holes in the blocking and to allow air flow from the holes into the attic along the underside of the roof deck. Or you can provide venting in other ways as described below, in which case you would not need the baffles at all.

Otherwise, you can consider other venting options which could be gable vents(if you have gable ends) which are louvered rectangular vents which are installed at the exterior wall in the attic, preferably with one at each end of the attic.

You could also consider the addition of 'mushroom' type attic vents that would be installed  through the roof and positioned about five feet up from the drip edge of the roof (out of the ice dam zone) in combination with a strip type ridge vent or another row of mushroom vents positioned near the ridge of the roof.

Regards,
Bruce Ryan II, RRO
Professional Roof Consultants, Inc.

Roofing

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Bruce A. Ryan II, RRO

Expertise

I offer solid knowlege of all types of Commercial and Residential Roofing, Waterproofing, and, Building Envelope systems. Experience ranges across low slope and steep slope roof systems. I am also well versed in matters regarding condensation and ventilation. I enjoy donating some of my time and knowledge to the betterment of others.

Experience

Bruce Ryan has 20 years of roofing, waterproofing, and building envelope consulting experience with PRC, with 5 years of commercial roofing experience prior to joining the firm. He became Vice President of the company in 1998. Bruce Ryan plays a key role in the development of practical, long-term roofing and waterproofing solutions, along with implementation of on-site forensic studies. Bruce also has a high level of experience with regard to the impacts of roofing materials and construction for demanding clients with heavily occupied structures.

Organizations
Oregon Construction Contractors Board Construction Specifiers Institute National Roofing Contractors Association The Institute of Roofing, Waterproofing, & Building Envelope Professionals Oregon Board of Investigators Installation Masters

Education/Credentials
University of Maryland BS Business & Administration Registered Roof Observer - RCI Private Investigator Certified EIFS inspector - Northwest Wall and Ceiling Bureau Certified InstallationMaster™ - The Installation Masters™ Training and Certification Program (developed by American Architectural Manufacturers Association)

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