Ice dam risk in Phillipsburg, NJ
Will your roof get ice dams in Phillipsburg, NJ?
10.6 dam days a winter
Moderate risk. On an ordinary house in Phillipsburg, conditions for an ice dam come on about 10.6 days in a normal winter, mostly in February and January.
Phillipsburg averages 41 inches of snow a year and about 42 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 Phillipsburg
| Attic | Dam days | Risk |
|---|---|---|
| Air-sealed and well insulated | 7.5 | Moderate |
| Typical, some insulation, not air-sealed | 10.6 | Moderate |
| Older or poorly insulated, warm attic | 14.6 | Moderate |
Sealing and insulating a typical attic takes out about 3.2 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 14.6 days.
Preventing ice dams on a Phillipsburg 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.
Which to spend on first: air sealing or heat cable.
Phillipsburg winter, month by month
| Month | Snow (in) | Days on ground | Dam days |
|---|---|---|---|
| January | 10.5 | 12.1 | 3.6 |
| February | 12.1 | 14.7 | 4.0 |
| March | 8.5 | 7.9 | 1.5 |
| April | 1.3 | 0.4 | 0.0 |
| October | 0.6 | 0.1 | 0.0 |
| November | 1.7 | 0.9 | 0.1 |
| December | 6.4 | 6.2 | 1.5 |
Phillipsburg next to nearby towns
Phillipsburg ranks 4 of 116 New Jersey cities here for ice-dam days, behind Hopatcong at 14.7 days.
- Easton, PA 2 mi, 10.6 days
- Bethlehem, PA 11 mi, 7.5 days
- Northampton, PA 16 mi, 7.5 days
- Allentown, PA 17 mi, 7.5 days
- Emmaus, PA 20 mi, 7.5 days
Where these numbers come from
NOAA 1991–2020 climate normals from Springtown 1 NNE, 9.8 miles from Phillipsburg. 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.