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Community and Q&A

Venting Hip Roofs

Joseph Dziedzic | Posted in General Questions on

After searching thousands of house plans we found a couple we like (variations of the same floor plan) which have a hip roof with an open (cathedral) ceiling along the center rear.  Then I read dozens of articles here advising of many issues that arise with (vented) hip roofs.  In this particular plan it appears the cathedral area ends before the peak of the roof, so does this mean there is a possibility for sufficient roof ventilation, presuming the cathedral section is properly vented?

Or should I just stick with gable roofs with a dormer or two for visual interest?  (Zone 5)

For reference, plans are here:
Craftsman House Plan – 3 Bedrooms, 4 Bath, 2683 Sq Ft Plan 12-1525 (monsterhouseplans.com)
Shingle House Plan – 4 Bedrooms, 3 Bath, 2755 Sq Ft Plan 12-747 (monsterhouseplans.com)

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Replies

  1. Patrick OSullivan | | #1

    To me, both look like a nightmare to properly vent.

    Also, both share in common what I think is a troubling detail. The two large gables intersect in a shallow valley. I would be forever worried about what weakness water would eventually find in that area.

  2. GBA Editor
    Martin Holladay | | #2

    Joseph,
    I suggest you read this article: "All About Roof Venting." You should pay particular attention to the section under the bold heading that reads, "Tricky roofs to vent: roofs with hips or valleys and mansard roofs."

  3. Expert Member
    Akos | | #3

    There is nothing inherently wrong with venting a hip roof, or even a hip roof with a cathedral ceiling. The issue usually comes when you add a lot of roof origami to the picture.

    Generally, house plans like you show are built with roof trusses. Unlike traditional lumber roofs, trusses provide much more space. You can spec trusses that have energy heels and provide enough space for insulation and venting.

    The bigger issue with both house plan is the roof valley that ends in a wall. Well built, this is at best a questionable detail and asking for water leaks.

    Bonus rooms above garages tend to be energy pigs. Detached garage is a much better option in most cases, plus it allows you to put windows on all four sides of the house. This also simplifies your house shape.

    1.5 story houses are about the same work to build as a 2 story and are way harder to air seal and make energy efficient. If you want more space, go for a two story build.

  4. GBA Editor
    Kiley Jacques | | #4

    Hi Joseph,

    Take a look at this article, A Vent for Every Roof, particularly the section titled, “Vents for difficult places.”

  5. Joseph Dziedzic | | #5

    Thanks all, appreciate all the feedback!

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