By design, a Hip roof has a much shorter 'ridge' than does a Gable roof - does this 'shortness' create a problem in providing adequate ventilation above the attic insulation, given that the 'ridge vent' length is much shorter?

Are there any disadvantages to a Hip roof vs a Gable roof?

Thanks.

A hipped roof is practically impossible to adequately vent, unless the venting is external - that is, above the roof sheathing.

Posted By Bob I on 15 Dec 2012 02:42 PM
A hipped roof is practically impossible to adequately vent, unless the venting is external - that is, above the roof sheathing.

Thanks Bob
Yikes!!!
Can you explain what you mean by 'external venting'? Does this mean those vents that you attach all over the roof that stick up a few inches?
If so, are these vents guaranteed to provide the correct venting or are Hip roofs just 'not a good idea'?
Thanks.

Depends on how square the house is; a rectangular house still has a ridge and mine has no ventilation problems. Hips roofs are stronger and give you better eaves all around.

by external vents, i mean sheath the roof, strap with 2x4s (tye vent channel) then sheath. Its the way a roof with added foam is vented.
I'm speaking specifically of roofs where the rafters are insulated. If the rafter are uninsulated a hip works well; the vent area necessary can be easily calculated and adjusted. You can also add ridge vents to the hips as well as the ridge.

Dr. Joe at buildingscience.com recently had something to say about the traditional formulas for balancing ridge and soffit vent areas. He feels that a big imbalance between ridge and soffit areas is not a big problem. In particular, see his step 5 on page 69 of this article:
http://www.buildingscience.com/documents/published-articles/resolveuid/b53082e3229e37734a779c742a6e0a10

For a rectangular hip roof with the same pitch on all four sides, the length of the ridge will be the difference in lengths of the long and short sides. Clearly, a square footpring has no ridge at all.

Thanks jonr,Bob I & DickRussell.