On Fri, 31 Jan 2020 03:31:10 -0800 (PST), Cindy Hamilton
wrote:

On Thursday, January 30, 2020 at 4:39:52 PM UTC-5, Clare Snyder wrote:
On Thu, 30 Jan 2020 03:21:22 -0800 (PST), Cindy Hamilton
wrote:

On Wednesday, January 29, 2020 at 8:57:39 PM UTC-5, micky wrote:
Do electric roof fans rust enough that they must be replaced?

My fan, in the pitched part of the roof, looks like new from the inside.
The plastic top, the metal screen**, and the metal frame below the
screen. all look perfect.

**Not wire screening but sheet metal with a lot of holes in it.

But the roofer who came yesterday wants to replace it, because he says,
it's rusting.

He also says the new one will be better, new thermostat, new humidistat.

My current thermostat works fine, I never take steamy showers or baths
so I don't need a humidistat.

I'm a little curious. Do steamy showers or baths affect the humidity
in the attic space that much? My bathroom vent fan exhausts to the
outdoors, so I've never thought about the humidity that might leak
around the fan housing. (The attic access--right outside the bathroom--
has a gasket.)

Cindy Hamilton
Not if you have a good vapor barier and all the light boxes etc are
properly sealed, and the fan vent duct is tight. A lot of IFs.

Ah. Vapor barrier. Nonexistent in my 1948 house. Not even a
tarpaper.

Cindy Hamilton
A good coat of oilpased enamel on the plaster does the job- spray
foam to seal around light boxes etc.