Ice dams in Reading
About 76 days a year cross freezing and back and 48 cm of snow falls, so meltwater runs down and refreezes at the eave, pushing water back up under the shingles; The median home dates from 1938, so most roofs have been replaced at least once and the seams and detailing underneath are of that era.
About 76 days a year cross freezing and back and 48 cm of snow falls, so meltwater runs down and refreezes at the eave, pushing water back up under the shingles
The median home dates from 1938, so most roofs have been replaced at least once and the seams and detailing underneath are of that era
Reading crosses freezing between night and day on about 76 days a year, and each of those cycles melts a little roof snow and refreezes it lower down.
How the damage actually happens
Heat leaking into the attic warms the middle of the roof deck while the eave, which overhangs unheated air, stays below freezing. Snow melts up high, runs down, and refreezes where the deck is cold. The ridge of ice that builds up holds the next lot of meltwater against the shingles, and shingles are designed to shed water downhill, not to hold it.
Reading averages about 48 cm of snow a year, and it is the snow that stays on the roof rather than the snow that falls which decides what happens at the eave.
What actually fixes it
- Air-seal the attic floor so heat stops reaching the deck - this is the real fix
- Insulate to the depth the code calls for, after sealing, not instead of it
- Ventilate soffit to ridge so the deck stays close to outside temperature
- Only then consider membrane at the eave, which limits damage rather than preventing ice
Heated cables are the opposite of a fix: they melt a channel through the ice, use electricity every winter, and leave the cause untouched. They have a place on a roof that genuinely cannot be ventilated, and nowhere else.
Prices in nearby cities
Allentown · Bethlehem · Harrisburg · Lancaster · Levittown · Scranton · York · Wilmington · Camden · Trenton · Towson · Perth Amboy