Ice Dam Prevention Calculator

Calculate the insulation R-value and ventilation needed to prevent ice dams based on your climate zone and current insulation.

Attic Floor Area

sq ft

Current R-Value

Roof Pitch

:12

IECC Climate Zone

Tab to move between fields

Target R-Value

Additional R Needed30

Insulation to Add9.4 inches

Ventilation NFA10 sq in

Estimated Cost$6,750.00

How to Use This Calculator

Enter the attic floor area (sq ft) and current insulation R-value.
Enter the roof pitch as rise over 12 inches of run.
Select your IECC climate zone to set the target R-value.
Review the target R-value, additional R needed, and insulation thickness to add.
Check the recommended attic ventilation NFA and estimated cost for the upgrade.

What each input means

Attic Floor Area: Total attic floor area in square feet
Current R-Value: Current insulation R-value (check label on existing insulation)
Roof Pitch: Roof pitch as rise over 12 inches of run
IECC Climate Zone: IECC climate zone for your location (1 = hot, 8 = subarctic)

Identify Input Parameters
4 parameters
Attic Floor Area = 1500, Current R-Value = 19, Roof Pitch = 6, IECC Climate Zone = 5 = 4 input(s) provided
Calculate Target R-Value
Target R-Value
49 = 49
Calculate Additional R Needed
Additional R Needed
30 = 30
Calculate Insulation to Add
9.4 = 9.4