Serving Anchorage through the Mat-Su Valley
Every winter, Anchorage homeowners deal with the same problems: water stains on the ceiling, icicles the size of baseball bats hanging off the eaves, and that sinking feeling when a drip shows up in the kitchen. Most of these problems didn't start when the snow hit. They started months earlier, with something going on in the attic that nobody checked.
We're a local Anchorage roofing company, and the majority of our winter calls come down to the same handful of issues. Here's what they are, how to catch them before they turn into real damage, and what the actual fixes look like.
Ice dams are the single biggest source of winter roof damage in Anchorage. If you've ever had water dripping from your ceiling in January, this is almost certainly why.
The mechanism is straightforward: heat escapes from your living space into the attic. That heat warms the roof deck, which melts the snow sitting on top. The meltwater runs down the roof toward the eaves — the coldest part, because they extend past the heated house. The water refreezes at the eaves, forming a ridge of ice. As more meltwater backs up behind that ice ridge, it has nowhere to go except under your shingles and into your house.1
The two primary causes are air leakage into the attic and poorly insulated attic floors.1 That's it. Ice dams are an attic problem, not a roof surface problem.
The fix is in the attic, not on the roof. When we show up to a home with ice dam damage, we typically find two things: detached vents and insulation with a very low R-value. Warm air is pouring into the attic space unchecked.
The real solution is:
Many homeowners assume their homeowner's insurance will cover ice dam damage. It often doesn't. Insurance companies frequently classify ice dam damage as "deferred maintenance" rather than a covered "sudden event."2 The logic is that if you'd maintained your attic insulation and ventilation, the ice dam wouldn't have formed. It's frustrating, but it's another reason to address the root cause before damage happens.
If ice dams are the symptom, attic insulation is the disease. Most of the winter roof calls we get trace back to an attic that isn't doing its job.
Anchorage sits in Climate Zone 7.3 The Department of Energy recommends attic insulation of R-49 to R-60 for this zone.4 A lot of older Anchorage homes have nowhere near that. When the R-value is too low, heat from your living space bleeds through the ceiling into the attic, warming the roof deck from below — and you get ice dams, condensation, or both.
A properly insulated and ventilated Anchorage attic should be cold in winter — close to the outside temperature. That means:
If your attic doesn't match this description, it's worth getting it inspected before the next winter.
This is one of the most common — and most overlooked — winter roof problems we see in Anchorage. Roof vents that work fine in summer get buried under snow in winter, and the results can look a lot like a roof leak.
Here's what happens: your bathroom fan or kitchen exhaust pushes warm, moist air up through a vent pipe that exits through the roof. In winter, snow covers that vent opening. The warm air hits the cold, blocked vent and condensates — or it melts the surrounding snow, which refreezes and creates a small ice dam right at the vent. Either way, water works its way back down the vent pipe and drips into your bathroom or kitchen ceiling.
When gutters freeze solid, water from snowmelt has nowhere to go. It backs up, pools behind the ice, and can work its way under your roofing material or overflow down your siding and into your foundation.
Frozen gutters are often a secondary symptom of ice dams — if ice is forming at the eaves, the gutters are going to freeze too. But even without a full ice dam, gutters packed with fall debris can trap water that freezes and expands, cracking the gutter or pulling it away from the fascia.
Heat cables (also called heat tape) are electric cables installed along the eaves and in gutters to prevent ice from forming. They're common in Anchorage, and for good reason — they work as a management tool.6
What heat cables do well:
What heat cables don't do:
Our recommendation: If you're dealing with ice dams, get your attic inspected first. Heat cables are a good supplemental measure — especially on sections of roof where insulation improvements alone won't fully solve the problem — but they shouldn't be your only line of defense.
Most of the problems in this article can be caught and fixed before winter starts — if you know what to look for. The best time for a roof and attic inspection in Anchorage is September, before the first snow locks everything down.
A fall inspection should include:
If you're not sure where your roof and attic stand heading into winter, we'll come take a look and give you a straight answer about what needs attention now versus what can wait.
-Robert Wilcox
Ice dams. The majority of winter roof calls we get are related to ice dam water leaks into the house. They're caused by heat escaping into the attic and melting snow on the roof, which refreezes at the eaves and backs water up under the shingles.1
Often, no. Many insurance companies classify ice dam damage as "deferred maintenance" rather than a covered sudden event.2 The reasoning is that proper attic insulation and ventilation would have prevented the ice dam. Check your specific policy, but don't assume you're covered.
Anchorage is in Climate Zone 7, and the Department of Energy recommends R-49 to R-60 for attic insulation in this zone.3 4 Many older Anchorage homes fall well short of this, which directly contributes to ice dams and heat loss.
Heat cables help manage ice dams by keeping a drainage channel open so meltwater can escape, but they don't fix the root cause.6 If your attic insulation is inadequate, heat cables are treating the symptom. They're most effective as a supplemental measure alongside proper insulation and ventilation.
Water dripping from a bathroom exhaust fan, moisture on the underside of vent covers, or water stains on the ceiling directly below a roof penetration are all signs. Gurgling drains or slow toilets can indicate a blocked plumbing vent. After heavy snowfall, vents can get completely buried.
September is ideal in Anchorage — after the summer roofing season but before the first snow. This gives time to address any insulation issues, repair damaged shingles or flashing, clean gutters, and test heat cables before they're needed.
Municipality of Anchorage — "Handout AG.30: Snow Removal Guidance" (40 psf minimum snow load requirement)
