Replies

1. GBA Editor
   Martin Holladay | Oct 28, 2015 09:30am | #1

   Diana,
   The term "vaulted ceiling" means different things to different people. If your ceiling is sloped right to the ridge -- with no horizontal ceiling at all -- then you don't have an attic. In that case, your roofer is correct. If you have something that looks like a gable vent on your gable, it's just a decoration, not a vent.

   However, not all insulated roof assemblies need a ridge vent. There are many types of unvented cathedral ceilings. Unless your roofer knows what type of insulation has been installed in your ceiling, it's impossible to know whether you need a ridge vent or not.

2. 
   LukeSkaff | Oct 31, 2015 02:20pm | #2

   To add to what Martin said, unless the cathedral ceilings has soffit vents on the eves and is built with baffles to allow an airspace behind the insulation (google "Provent Attic Ventilation System" for example) then a ridge vent will not provide a clear ventilation path.

3. 
   davidmeiland | Nov 01, 2015 09:19am | #3

   Hmmm. Rightly or not, I use the term "vaulted" to refer to a ceiling where the ceiling and roof planes are not parallel--such as with scissor trusses--and the term "cathedral" to refer to a ceiling that is parallel to the roof, almost always because the ceiling is attached to the bottom of the rafters.

   With a vaulted ceiling, you could easily have an enclosed space of sorts, even one that is accessible. I have been in quite a few "attics" made with scissor trusses and accessible from inside the house. Some of these had gable vents, more of them had eave/ridge venting.

   As Martin and Luke are saying, it is necessary to inspect carefully to figure out what is going on. If there are eave vents but no ridge vent, and there are vent channels under the roof deck, a ridge vent is probably a good idea. Sometimes you can peek in from under the eaves and see exactly what is going on. Other times there is no way to see what is going on without removing drywall (or roof deck, which they could easily do if they are stripping the roof).

4. GBA Editor
   Martin Holladay | Nov 01, 2015 09:45am | #4

   David,
   You're right that the scissors truss possibility complicates this issue, because a roof with scissors trusses can have an attic whose existence isn't obvious. Thanks for your comments.

5. GBA Editor
   Martin Holladay | Nov 01, 2015 11:09am | #5

   David,
   On "vaulted ceiling" vs. "cathedral ceiling" -- you're right that many builders and designers make the same distinction that you explained. But not everyone uses the terms this way, which is why I wrote that "the term 'vaulted ceiling' means different things to different people."

   Strictly speaking, a vaulted ceiling is curved, forming one of three types of vaults: a barrel vault, a rib vault, or a groin vault. But accurate use of the term has faded in recent decades.

   I suppose that a nitpicker could also point out that most ceilings described as "cathedral ceilings" aren't really cathedral ceilings... (In fact, most actual cathedral ceilings are also vaulted.) Clearly, vocabulary changes over time.

   .

   
6. 
   davidmeiland | Nov 01, 2015 05:14pm | #6

   Martin, good refresher there. Thirty years ago I studied hard to know all of that, but then I became a carpenter and the process of only knowing the absolutely necessary kicked in.