Ice dam risk in Dayton, OH
How often ice dams form in Dayton
5.7 dam days a winter
Moderate risk. On an ordinary house in Dayton, conditions for an ice dam come on about 5.7 days in a normal winter, mostly in January and February.
Dayton averages 12 inches of snow a year and about 22 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 Dayton
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 3.2 | Low |
| Typical, some insulation, not air-sealed | 5.7 | Moderate |
| Older or poorly insulated, warm attic | 8.7 | Moderate |
Sealing and insulating a typical attic takes out about 2.4 days a winter here. It drops the risk from moderate to low.
Preventing ice dams on a Dayton 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.
Which to spend on first: air sealing or heat cable.
Dayton winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 6.9 | 9.4 | 2.8 |
| February | 1.5 | 5.1 | 1.3 |
| March | 1.7 | 1.8 | 0.3 |
| November | 0.1 | 0.1 | 0.0 |
| December | 2.1 | 5.3 | 1.3 |
Dayton next to nearby towns
Dayton ranks 154 of 176 Ohio cities here for ice-dam days, behind Euclid at 24.8 days.
- Riverside, OH 4 mi, 5.7 days
- Trotwood, OH 7 mi, 5.7 days
- Vandalia, OH 7 mi, 7.4 days
- Kettering, OH 7 mi, 5.7 days
- Huber Heights, OH 7 mi, 7.4 days
Where these numbers come from
NOAA 1991–2020 climate normals from Dayton Mcd, 0.5 miles from Dayton. 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.