Frozen WhirlyBirds

[Merril M. Dean]

We have a 4 level split home with whirly birds on the two roof levels.
Once it hits minus 40 the whirlybird above the bedrooms frosts up
between the turbine vents and won't spin. (The whirlybird above the
livingroom/kitchen area is fine). It has happened three winters in a
row now. The fact that it isn't spinning means the prevailing winds
blow snow into our attic and so....in the spring, we either shovel out
snow and insulation, and reinsulate, or watch our ceilings drip water.
Both bathrooms on the upper floor are properly vented and we run the
ceiling fans in them all winter. We do have a problem with humidity in
the house. It usually runs around 60% -- I can't get it lower with
ceiling fans and bathroom fans -- is this the cause of the whirlybird
problem? If so, is there anything cheaper than a dehumidifier to fix
it?

[PBitschura]

The fact that snow will blow into your attic under any circumstance
suggests the your turbine vents intake air at certain times. That plus
your admission that you have a moisture problem leads me to the conclusion
that you have insufficient intake ventillation. In order to clear moist
attic air, cooler air must bedrwn into the attic from your soffit or other
source. A convection loop is then set up in which warm air escapes at
your ridge. Inadaquate attic ventillation reduces the life of your roof,
promotes rot of your deck and framing members, and reduces the efficiency
of your attic insulation. Temporary solutions include increased use of
exhaust fans, opening some windows for 5-10 minutes to equalize indoor
relative humidity, and applying a silicone or graphite based lubricant to
the bearing in your turbine vents to isolate them from moisture which
condences and freezes on them when cold temperatures exist. I hope this
helps. PBits...@aol.com