A Brief Break & Sweaty Floors

January 11, 2006

All is well with the world again today…the sunshine was blinding between the showers, and temperatures were back down to reasonable for January (45-50).  That freakish warm stuff was gone.

Which brings me to sweaty talk.  No, you know what I mean…dewpoint & condensation talk.

Do you have a garage that isn’t very well insulated (or none at all like mine)?  Does it annoy you when you come out one morning in the wintertime (today!) and the whole floor is wet?  It sure annoys me.  Here’s why/how it happens:

1.  The cement cools down during a chilly spell, let’s say to 45 degrees.

2.  Then warmer air moves in, often right after a cool spell.  Air temp is 50-55, dewpoint is 50 (like yesterday).

3.  As soon as the warm air arrives and your cold cement floor is begins acting just like the tall cold beverage that gets all wet on the outside on a summer day.  Air in contact with the floor is cooling to the dewpoint temperature, which allows water vapor in the air to condense onto the floor.  That’s it, the floor suddenly turns wet.

4.  To dry the floor, you either need to warm the floor (heat the garage temporarily), or wait for the dewpoint outside to drop back down below the floor temp.  I’ve noticed just a change back to "normal" cool January weather (like tonight) takes care of the problem.  It’s always the worst right after a cold spell when we go into a warm/wet pattern.

Weatherwise tonight, we are in a break, but another system moves in tomorrow.  It’ll be pretty wet then through Friday, then showery/cool for the weekend.  Sunday morning the snow level may drop down as low as 1500′, but no lower.  Next week we stay with seasonably cool/wet weather.  No big warm ridge in sight OR big ridge offshore to channel dry arctic air towards us.  Notice even the bullish GFS has backed way off any sort of cold spell.  It seems to do that regularly each winter.