Dense-Pack Insulated Hot roof designs for sloped roofs:

This article series describes the dense-pack insulation approach for un-vented cathedral ceilings and similar under-roof spaces. We provide data & references on the dense-pack insulation approach to un-vented hot roof designs for buildings.

Dense packing sloped roofs, residential: Is there Data Supporting Dense-Packed Un-Vented Sloped Roofs?

Reader Question: Is there any data out there on condensation issues when dense packing a sloped roof.

Cape cods and other dormer type construction have ceilings that traditionally have ventilation to the upper attic area and out the ridge vent. Sometimes these sloped roof areas have battens of fiberglass insulation.

We are running a residential program in Wisconsin and the contractors have been dense packing the sloped roof/ceiling in these areas.

Their anecdotal evidence is that they have had no problem with condensation or moisture. Are there any resources out there on data for zones 4 and 5.

By the way, I want to thank you again for joining us on the radio program, Constructive Solutions, in Wilmington NC and answering listeners questions. - J.A., Madison WI, 5/15/2012

Our sketch (above left) shows the traditional 1940's - 1960's design for insulating and venting a cape cod roof.

Current design, among those who are venting the roof at all, provides continuous soffit or eaves intake, continuous ridge outlet venting, and we eliminate the gable end louvered vents. - Ed.

Reply: there is science supporting un-vented roofs provided construction is perfect and no roof leaks occur

Also see the notes in our hot roof article (above) and also
at ROOF VENTILATION NEEDED?.

Roof venting for cathedral ceilings remains a contested issue, though as we elaborate below, there has been some expert work and plenty written about the topic.

Roof venting for buildings with attics is also discussed below.

Our photo at left is not a Cape Cod style home, but this New York house illustrates differential snow melting indicating where heat is being lost into the roof structure.

Even in climates not subject to freezing temperatures and heavy snowfall, the snow-melt patterns on these Northern homes can inform us about how heat and air can move from the occupied space into the under-roof space of a building.

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Continue reading at HOT ROOF DESIGN CONCLUSIONS or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

Or see these

Recommended Articles

• CATHEDRAL CEILING INSULATION
• CAPE COD ROOF VENT or DENSE PACK INSULATE

Suggested citation for this web page

INSULATE ROOF with DENSE PACKING at InspectApedia.com - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.

Or see this

INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING VENTILATION

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Citations & References

In addition to any citations in the article above, a full list is available on request.

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