The freeze-thaw metronome
St. Louis winters rarely stay frozen — they oscillate, crossing 32 degrees again and again. Each cycle, meltwater slips into hairline gaps and refreezes, expanding nine percent and prying joints wider: eave edges, flashing laps, mortar joints, gutter fasteners. One deep freeze does less damage than thirty crossings.
Ice dams: the classic county failure
Heat leaking into the attic melts the snow blanket from below; the melt refreezes over the cold eaves into a dam, and standing water backs up under the shingles. Stains at the top of exterior walls in February are the signature. Cure: air-seal the attic floor, insulate to code, ventilate to keep the deck cold, and membrane the eaves at replacement.
Gutters take the collateral damage
Ice loading pulls gutters from fascia a millimeter a winter until the fall is visible. Beyond replacement cost, a tilted gutter dumps water at the foundation and soaks the fascia — check the line with a level each spring in Kirkwood's and Webster Groves' older stock.
Hail finishes what winter starts
Spring hail lands on shingles that winter has already embrittled at the edges. It's why county hail claims cluster at eaves and rakes. Class 4 shingles resist the spring half; eave membrane and good ventilation handle the winter half.
The eave-first inspection
In St. Louis we inspect from the edges inward: eave membrane, drip edge, first courses, gutter line, then flashings, then field. Free, photographed, and itemized — and best scheduled in fall before the metronome starts.
Frequently Asked Questions
Why do St. Louis roofs leak in late winter?
Ice dams — attic heat melts snow, the melt refreezes over cold eaves, and standing water backs up under shingles. Insulation, air sealing, ventilation, and eave membrane are the cure.
How do I stop ice dams in Kirkwood or Webster Groves?
Air-seal and insulate the attic floor, keep the deck cold with balanced ventilation, and install ice-and-water membrane at eaves and valleys at replacement. Heat cables only treat symptoms.
When should St. Louis roofs be inspected?
Fall (before freeze season) and after any spring hail. Edge-focused inspections catch the county's signature failures early.
Are Class 4 shingles worth it in St. Louis?
Yes — the county's hail frequency makes impact-rated shingles one of the region's best-value upgrades, especially paired with proper eave protection.
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