Kittatinny Roofing

Where the melt stops

The mechanism is simple and it repeats every winter. Heat escaping into the attic melts snow against the deck. The water runs down, reaches the overhang where there is no heat underneath, and freezes again. What builds up there works back under the covering.

A roof here rarely gives out in the field. On old housing it gives out where two centuries meet. Where this sits on the roof.
Garage Point 1: the ridge 1 Point 2: the field of the covering 2 Point 3: the valleys 3 Point 4: flashing at a shared wall 4 Point 5: a penetration 5 Point 6: the overhang 6
  1. 1 The ridge. The highest course, and on slate the one most often reset by hand.
  2. 2 The field. Slate on the older stock, shingle on the rest. Two very different clocks.
  3. 3 Valleys. Where leaf litter settles, and where a slate roof usually ends its life.
  4. 4 Wall flashing. The party wall of a row or twin, rising through a roof two houses share.
  5. 5 Penetrations. Holes cut on purpose. When access is awkward they get sealed instead of rebuilt.
  6. 6 The overhang. Where meltwater from a warm attic reaches cold framing and stops.

Why the overhang is different

The roof above the living space is warmed from below whether anyone intends it or not. The part that projects past the wall is not. That temperature line sits right where the covering is thinnest in effective terms, and it is where the water arrives already moving.

The wider the overhang, the sharper the effect. Much of the post-war housing north of Bethlehem and through Whitehall was built with generous eaves, which is pleasant in July and unhelpful in February.

What actually causes it

Heat loss, almost always, and specifically heat that reaches the deck instead of staying in the house. Insulation added over the decades without touching the ventilation is the usual history here: the attic became warmer and the path for that warmth to leave was never opened.

Which is why treating the symptom rarely settles it. Removing ice from an edge is a February job; making the attic stop feeding it is a replacement-day job.

What belongs in the quote

A membrane at the eaves that extends well past the inside face of the exterior wall, intake ventilation at the soffit that is not blocked by insulation, and exhaust at the ridge sized to match. Those three together are the fix. Any one of them alone is a partial measure.

The other ways roofs fail

Areas covered