Ice dam risk in Carpentersville, IL
Ice dams in Carpentersville, IL: how often
14.7 dam days a winter
Moderate risk. On an ordinary house in Carpentersville, conditions for an ice dam come on about 14.7 days in a normal winter, mostly in January and February.
Carpentersville averages 32 inches of snow a year and about 44 days with snow on the ground. Most of it comes and goes within a few days. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
What your attic does to that number in Carpentersville
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.0 | Moderate |
| Typical, some insulation, not air-sealed | 14.7 | Moderate |
| Older or poorly insulated, warm attic | 24.4 | High |
Sealing and insulating a typical attic takes out about 7.7 days a winter here. It does not move the risk band, but it shortens every dam. An older house with a warm attic should expect closer to 24.4 days.
What to do about ice dams in Carpentersville
- Air-seal the attic floor: the gaps around the hatch, light fixtures, plumbing stacks and the top plates of interior walls. This is the fix that removes the cause, and it usually costs less than a season of contractor ice removal.
- Rake the bottom three or four feet of roof after any storm that leaves more than about six inches, from the ground with a roof rake.
Which to spend on first: air sealing or heat cable.
Carpentersville winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 9.5 | 16.6 | 6.3 |
| February | 8.0 | 12.6 | 4.3 |
| March | 3.7 | 3.8 | 0.8 |
| April | 0.8 | 0.5 | 0.0 |
| November | 1.4 | 1.3 | 0.2 |
| December | 8.7 | 9.4 | 3.0 |
Carpentersville next to nearby towns
Carpentersville ranks 61 of 225 Illinois cities here for ice-dam days, behind Arlington Heights at 21.5 days.
- Algonquin, IL 3 mi, 14.7 days
- Lake in the Hills, IL 4 mi, 16.8 days
- Elgin, IL 6 mi, 14.7 days
- Cary, IL 7 mi, 18.8 days
- Pingree Grove, IL 8 mi, 14.7 days
Where these numbers come from
NOAA 1991–2020 climate normals from Elgin, 4.2 miles from Carpentersville. A dam day is a day with snow on the roof and freezing at the eave while heat or sun melts the snow above it. This describes a normal winter, not this one.