Do I have enough attic intake ventilation

 ShingleVent II install


Ed,

You mentioned proper balance of venting. I am building my 2-story house which has 1342 sq ft on the second floor. Since I am putting ShingleVent II at the ridges and have drilled holes in the blocking at the eaves my calcs say I need 4.47 sq ft of venting (1/300). I have 5 sq ft at the ridges but only 3.27 at the eaves. Is this a problem since I have 8.27 sq. ft. total?

thanks,

stan

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6 Comments on “Do I have enough attic intake ventilation”

  1. rightwayroofing Says:

    Re: Balancing Intake and Exhaust, ShingleVent II
    ——————————————————————————–
    Under the Principles Of Attic Ventilation guidelines and most building codes, (which are never never checked and enforced), your 1,342 sq ft / 300 = 4.47 sq feet of TOTAL ventilation required. Although this is not a “Balanced” ventilation system, it does meet the requirements for the “Minimum” standards.
    Actually the intake ventilation is of more importance than the exhaust portion of the balanced ventilation equation, surprisingly some might think.
    If at all possible, can you provide additional intake vents to bring up the intake to an equal sq in amount as the 40 feet of ridge vent you are installing?
    Or, can you provide either a “Smart Vent” for additional intake ventilation under the first course of shingles if they have not been installed yet? Smart Vent is manufactured by DCI Products, Inc.
    Or, Google, “fascia vents” and you will come up with 3-5 different manufacrturers of similar conceptual products right on the 1st page of hits. I know for a fact, because I just provided the link for a HO on the DIYChatroom.com site, which is the sister site to ContractorTalk.com. So, you can just click on DIYChatroom.com, and check my user profile, Ed The Roofer, and see my recent posts and you will find the products I mentioned.
    Most ventilation studies recommend a 60 % ratio of intake ventilation to a 40 % ratio of exhaust ventilation. I believe that ratio comes from the Home Ventilation Institute, HVI.
    Do yourself a favor and order the free guide from Air Vent Corporation,(Gibraltar), and order the “Principles Of Attic Ventilation, as it is only about a 16 page booklette, but extremely informative.
    Ed
    [QUOTE=sroskens]Ed,
    You mentioned proper balance of venting. I am building my 2-story house which has 1342 sq ft on the second floor. Since I am putting ShingleVent II at the ridges and have drilled holes in the blocking at the eaves my calcs say I need 4.47 sq ft of venting (1/300). I have 5 sq ft at the ridges but only 3.27 at the eaves. Is this a problem since I have 8.27 sq. ft. total?
    thanks,
    stan[/QUOTE]

  2. Nancy Says:

    Ed the Roofer, you rock. I found out more about roofing (which I wish I knew 12 years ago) in just the last 10 minutes since I found this site. Thanks for the info on hiring a roofer. I printed it out for future reference and I know it will come in handy. My ridges are disinigrating and it must be from improper ventilation or no ventilation on installation. Just my luck!!! Just wondering, is the material on the ridges different form the actual roof?

    Thanks again…………………..

  3. rightwayroofing Says:

    Nancy,

    Thank you very much for the comments and for supporting this blog site. Since this site is very new, I am very appreciative to help out some more if you have further questions.

    Sincerely,

    Ed The Roofer

  4. Kathy Says:

    Just had new roof installed Landmark 30 yr architectural shingles. The shingles on the rake edges don’t have the same overhang distance as you look up to the peak area, the shingle cap on one of the ridge vents hangs over one side of the vent more than the other and shingles are uneven. The shingles around the skylites don’t look very good and the lower flashing is wavy (they reused flashing that was on skylites and I would have preferred to purchase a new kit. Company says area around lites installed per roofing manuals and that flashing will never lay flat because of type shingles we purchased, but I have seen skylites on other architectural shingled roofs that look very nice, not like ours. Before I pay the bill I wanted another opinion as to whether I am being too picky.

  5. rightwayroofing Says:

    Kathy,

    If you could e-mail or post some photos of the unevenness of the shingle overhangs in question, I would be able to better assist you.

    The extra length of shingle sticking out over the ridge vent can just be trimmed back to be equal to the opposite side for cosmetic appearances.

    The rake edge shingle, if they are all overhanging the gable edge by at least 1/2″ or more also could be trimmed back for a more uniform appearance.

    As far a the sheet metal flashings around the skylights, I need to ask what was there appearance prior to the new roof installation?

    Even after applying a new roof, the sheet metal should fit snug andd tight to the shingles, unless you had cedar shakes or a tile roof with an uneven profile installed, which you did not.

    Please expand on or include photos of how the shingle do not look very good around the skylights.

    If you are unable to post a photo here, (I don’t know yet, as this blog site is new to me), then you could e-mail them to;

    rightwayroofing@sbcglobal.net

    I hope I can assist you further and as a side note, please inform me of which part of the country you are from. Just the largest city nearby and the state is all I need. Sometimes the answers may be different for differing regional conditions for some questions.

    Ed The Roofer

  6. Kathy Says:

    Ed, with your feedback and suggestions which mirrored other opinions we received, we have resolved all outstanding issues from our recent reroofing job (my original post Aug 29th). The project manager listened to our concerns and fixed everything to our complete satisfaction. The extra time you took to review photos and provide additional comments was a big help to us. Thanks for sharing your knowledge!


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