Return to the Home Repair Forum | Post a Follow-Up

Insulation and Ventilation

Posted by patriotic (My Page) on
Fri, Sep 23, 11 at 18:42

I am building an addition in Nebraska and need some advice on insulation and ventilation in the attic. I have closed cell foam in the walls (5 inches) and am scheduled for R38 batt (11.5 inches) with R19 batt (5.5 inches) on top of the R38, both over a 6 mil plastic vapor barrier. This is above a bathroom and closet on the hot (south) side of the house.
I have stapled styrofoam baffles 8 ft long in every rafter opening (14) to the underside of the roof that should help air flow from the eave vents to the ridge vent. The top of the openings on the baffles are more than 36 inches above the attic joists (attic floor). Roof slope is 5/12 and the distance from attic floor to ridge is 5 feet at the peak.
My concerns are:
1) Is a certain "volume" of air required in the attic to prevent condensation?
2) Is there something I am missing?
3) Can too much insulation cause havoc and how?

Thanks in advance for any advice.

Follow-Up Postings:

RE: Insulation and Ventilation

Ask the local building official.

RE: Insulation and Ventilation

snoonyb's somewhat terse reply is pretty accurate. There are so many variable factors involved - including but not limited to local climate, roof design and type, exterior treatment on the roof, insulation type - that you're going to need to seek out specific local advice. Even then, recommendations change with pretty consistent regularity.

 o Post a Follow-Up

Please Note: Only registered members are able to post messages to this forum.

    If you are a member, please log in.

    If you aren't yet a member, join now!

Return to the Home Repair Forum

Information about Posting

  • You must be logged in to post a message. Once you are logged in, a posting window will appear at the bottom of the messages. If you are not a member, please register for an account.
  • Please review our Rules of Play before posting.
  • Posting is a two-step process. Once you have composed your message, you will be taken to the preview page. You will then have a chance to review your post, make changes and upload photos.
  • After posting your message, you may need to refresh the forum page in order to see it.
  • Before posting copyrighted material, please read about Copyright and Fair Use.
  • We have a strict no-advertising policy!
  • If you would like to practice posting or uploading photos, please visit our Test forum.
  • If you need assistance, please Contact Us and we will be happy to help.

Learn more about in-text links on this page here