Ice dam risk in Waupun, WI
How often ice dams form in Waupun
26.8 dam days a winter
High risk. On an ordinary house in Waupun, conditions for an ice dam come on about 26.8 days in a normal winter, mostly in January and February.
Waupun averages 43 inches of snow a year and about 74 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 Waupun
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 11.1 | Moderate |
| Typical, some insulation, not air-sealed | 26.8 | High |
| Older or poorly insulated, warm attic | 46.3 | Severe |
Sealing and insulating a typical attic takes out about 15.7 days a winter here. It drops the risk from high to moderate. An older house with a warm attic should expect closer to 46.3 days.
Preventing ice dams on a Waupun 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.
Waupun winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 13.0 | 23.9 | 10.1 |
| February | 10.6 | 21.4 | 8.1 |
| March | 6.6 | 9.4 | 2.4 |
| April | 1.7 | 0.9 | 0.1 |
| May | 0.1 | 0.0 | 0.0 |
| October | 0.4 | 0.1 | 0.0 |
| November | 2.1 | 2.4 | 0.5 |
| December | 8.8 | 15.4 | 5.6 |
Waupun next to nearby towns
Waupun ranks 41 of 98 Wisconsin cities here for ice-dam days, behind Wausau at 41.6 days.
- Beaver Dam, WI 12 mi, 26.8 days
- Fond du Lac, WI 18 mi, 27.6 days
- Hartford, WI 28 mi, 26.7 days
- Oshkosh, WI 28 mi, 27.2 days
- Watertown, WI 31 mi, 22.3 days
Where these numbers come from
NOAA 1991–2020 climate normals from Beaver Dam Wwtp, 14.1 miles from Waupun. 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.