Roof vent with an open/close switch for cathedral ceiling?

The guy who owned my house before me did a very nice looking renovation in my living room. He took out the attic leaving a high cathedral ceiling with the rafters and planks of wood visible. It looks like a ski lodge. I think they're calling these houses "bungalofts" now or something.
There is no insulation. There are no roof or soffit vents.
It's a little rough keeping the room comfortable in winter, but with a ceiling fan and a small space heater I get by.
In summer with the central AC it's also tough to keep the room cool, but so far so good.
The main problem in summer is condensation. There is one small area on my ceiling that drips water onto my floor (not much, but enough to be a problem) but only when the sun is high/hot and the AC is on, especially on the more humid days. The water seems to form around some of the exposed nails/screws (probably holding down the shingles from outside) in the ceiling.
The water is usually dark and oily looking which makes me wonder if it really is condensation. It might be that water somehow gets under the shingles when it rains but it doesn't get into the house until the sun heats up the roof. But for now I'm working under the assumption that it's just condensation. [Although, the last few days have been unusually hot and humid and there has been no water dripping at all.]
So...If I had a vent on my roof the extreme hot air could escape in summer, probably reducing or eliminating my condensation problem. But in winter this vent would need to be closed.
Does anybody out there know of a roof vent that can be opened in summer yet switched off in winter?
[I've got some problems with ice dams and water getting into the house (in a different area of that ceiling, 2 areas actally) in winter too, but that's for another thread I guess. Looks like I'll have a layer of ice and water shield installed and maybe some heating cables on the roof.]
Nice looking reno...everybody loves the way my house looks, but a pain in the ass.
Any thoughts, tips, advice, etc. appreciated.
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Joey Goldstein
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says...

Since it's going to be in a visible location, how about a good quality skylight that opens?
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snipped-for-privacy@phred.org is Joshua Putnam
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Joshua Putnam wrote:

That's worth considering. Thanks.
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Joey Goldstein
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I think you will be fighting a loosing battle. You need to keep the underside of the roof the same temp as outside to avoid ice dams and condensation on nail tips.
To properly solve the problem you will need to add ventilation at ridge and soffit, build a small attic and insulate.
Your "attic" only needs to be a couple of inches high. Your ceiling could be decorative and made to look like rafters and sheathing.
You could also build you attic on top of your existing roof if structure would accommodate it.

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No wrote:


Thanks for the learned advice. I appreciate it.
But "properly" is a big word and an expensive one. <g> What do you think the long-term ramifications are if I do *nothing*?
Will the ice dams get worse over time? Or does it just depend on the way each winter season unfolds? My first winter here was fine.
I've been told that if I put down some "ice and water shield" that it is highly unlikely that any water will get into the house in the event of another ice dam. And installing some roof heating cables can reduce the magnitude and effects of any more ice dams that occur. (Note: Part of the ice dam problem is that my neighbor's house is so close to mine that our eaves actually overlap a bit. This is the side that would get the heating cables.) Are these two measures worth doing, or am I just peeing into the wind?
Will the moisture from the condensation in summer create other problems as the years go by?
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Joey Goldstein
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