Allow me to remind, hit the refresh button….
This weather is PERFECT for creating ICE DAMS….and this weekend it will really get BAD..the perfect storm!
ICE DAMs are formed by 3 things…kinda like a three legged stool
1) weather conditions: snow on roof, frigid temps
2) insulation factor: code is R-49 (which you know, I know)
3) ventilation: in attic
To expound on the above:
Weather conditions: the snow on the roof, typically when greater than 4″ acts as a “blanket” trapping heat inside, accelerating the melting of the snow creating “meltwater” running down the roof shingles, under the snow not visible to the eye, running into the frozen metal (aluminum, copper) and eventually freezing….creating blockage or a dam…and either going to flow over the gutter…up the valley or up the roof line.
Insulation factor: in the winter because your furnace is on, the heat in your house is rising…is going thru the insulation..the less insulation you have the more heat goes into your attic. Code now requires R-49..that’s almost 14″ of blown-in cellulose!….the warmer the attic, the faster the snow melts…more meltwater more potential for bigger and badder ice dams.
Ventilation: Intake, exhaust, kitchen and bathroom venting. Code requirements require 1sq ft of ventilation to every 300sq ft of attic (sq footage)..additional requirements include a balanced ventilation system…meaning equal air intake to air exhaust…1sq ft exhaust to 1 sq ft of intake…INTAKE is extremely important…bring in the fresh, drier, cooler air to move faster the existing warmer, damper attic air. And the introduction of any bath or kitchen air NOT exhausting THRU THE ROOF or just dumping into the attic adds additional moisture and heat into the attic…creating warmer air and hot pockets
How to fix: NO PERFECT FIX….to help slow down the build up….remove 6′ of snow on the roof where gutters are….calcium chloride in panty hose..in the gutter to slow down the build up of ice……trying to keep water flowing
In the REAL world..if the salt or melting product used on the roads is NOT working because it is too cold, and these products were designed specifically to do this job….and this has problems….in this weather!!!????..and there is warmer air in your attic melting snow….a little pro-active effort on your roof…can yield positive results