Ice dam risk in Palatine, IL
Will your roof get ice dams in Palatine, IL?
21.5 dam days a winter
High risk. On an ordinary house in Palatine, conditions for an ice dam come on about 21.5 days in a normal winter, mostly in January and February.
Palatine averages 39 inches of snow a year and about 64 days with snow on the ground. Snow that lies that long is what turns a little attic heat into a ridge of ice at the eave. 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 Palatine
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 9.9 | Moderate |
| Typical, some insulation, not air-sealed | 21.5 | High |
| Older or poorly insulated, warm attic | 36.0 | Severe |
Sealing and insulating a typical attic takes out about 11.6 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 36.0 days.
Preventing ice dams on a Palatine roof
- 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.
- At the next reroof, ask for ice-and-water membrane under the shingles from the eave to at least 24 inches inside the wall line. It does not stop a dam; it stops the leak when one forms.
Which to spend on first: air sealing or heat cable.
Palatine winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 12.6 | 20.2 | 7.8 |
| February | 8.5 | 18.6 | 6.6 |
| March | 4.6 | 8.2 | 1.8 |
| April | 1.1 | 0.6 | 0.0 |
| October | 0.1 | 0.0 | 0.0 |
| November | 2.0 | 2.2 | 0.4 |
| December | 9.6 | 14.5 | 4.8 |
Palatine next to nearby towns
Palatine ranks 2 of 225 Illinois cities here for ice-dam days, behind Arlington Heights at 21.5 days.
- Rolling Meadows, IL 3 mi, 21.5 days
- Arlington Heights, IL 3 mi, 21.5 days
- Barrington, IL 5 mi, 21.5 days
- Buffalo Grove, IL 5 mi, 18.6 days
- Lake Zurich, IL 6 mi, 18.6 days
Where these numbers come from
NOAA 1991–2020 climate normals from Barrington 3SW, 6.1 miles from Palatine. 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.