Ice dam risk in Greenville, OH
How often ice dams form in Greenville
7.4 dam days a winter
Moderate risk. On an ordinary house in Greenville, conditions for an ice dam come on about 7.4 days in a normal winter, mostly in January and February.
Greenville averages 25 inches of snow a year and about 27 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 Greenville
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 4.0 | Low |
| Typical, some insulation, not air-sealed | 7.4 | Moderate |
| Older or poorly insulated, warm attic | 11.6 | Moderate |
Sealing and insulating a typical attic takes out about 3.4 days a winter here. It drops the risk from moderate to low. An older house with a warm attic should expect closer to 11.6 days.
What to do about ice dams in Greenville
- 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.
Greenville winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 8.3 | 10.7 | 3.3 |
| February | 6.6 | 8.0 | 2.2 |
| March | 3.9 | 2.3 | 0.4 |
| April | 0.4 | 0.1 | 0.0 |
| October | 0.2 | 0.1 | 0.0 |
| November | 0.8 | 0.5 | 0.1 |
| December | 4.8 | 5.6 | 1.4 |
Greenville next to nearby towns
Greenville ranks 118 of 176 Ohio cities here for ice-dam days, behind Euclid at 24.8 days.
- Piqua, OH 20 mi, 7.4 days
- Troy, OH 22 mi, 7.4 days
- Clayton, OH 23 mi, 7.4 days
- Englewood, OH 23 mi, 7.4 days
- Richmond, IN 24 mi, 9.2 days
Where these numbers come from
NOAA 1991–2020 climate normals from Dayton International Airport, 25.3 miles from Greenville. 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.
- The weather station is 25 miles away, far enough that local snow can differ.