Serving Salt Lake City, UT & Nearby Areas
(385) 438-3591
Serving Salt Lake City, UT & Nearby Areas
(385) 438-3591
Snow melts from underneath, where it touches your shingles. That's because heat is escaping your attic into it. That makes meltwater slow. So instead of rain running off in minutes you get days of water standing against the roof. As I tell homeowners every February, that is when you find out whether you had a good roofer.
Treat a snowmelt leak as a ventilation and detailing problem, not a shingle problem.
Meltwater is driven by attic heat and sits for days. So it tests laps and flashings that rain never reaches.
Have the attic assessed for intake and exhaust ventilation before anyone touches the roof surface.
In Utah the snow on your roof is being melted by your own attic. Fix the heat that is escaping and you fix the leak.
Mattie Tueller, Master Roofing
This is the piece that makes the whole thing click, and almost nobody is told it.
You would assume a snowpack melts from the top down, warmed by sun and air. On a roof over a heated house, the more important melting happens at the bottom, right where the snow touches the shingles. Heat escaping from your living space into the attic warms the underside of the roof deck. That warmth melts the layer of snow in contact with it.
The consequence is a slow, continuous trickle of water underneath an insulating blanket of snow, running down the roof surface with nowhere to go quickly and no sun or wind to dry it. That water can be moving across your roof for days while the visible snowpack barely changes.
This is why the leak often shows up in a stretch of cold, dry weather with no precipitation at all. Nothing fell out of the sky that week. Your own house was doing the melting.
Roofs shed water. That is the actual mechanism: shingles overlap so that water running downhill passes over each lap and keeps going. It is a system built around water that is moving.
Rain cooperates with that design: a hard Utah thunderstorm dumps a lot of water. But it runs off in minutes and the roof dries.
Snowmelt does the opposite. It arrives slowly, with a snowpack holding it in place. It can stay against the roof for days. Standing water does not respect a lap. Given time it:
So a snowmelt-only leak is really diagnostic. It usually means the roof is not broadly failing, it means one or more details were built for rain and are now being asked to hold back standing water. That is a workmanship standard question. It is exactly the kind of thing that stays hidden for years until the right winter comes along.
The same mechanic produces the more dramatic version of this problem.
Meltwater generated by attic heat runs down the roof toward the eave. The eave overhangs open air. So it is not warmed from below and sits at outside temperature. When the water reaches that cold edge, it refreezes. The ice builds into a ridge along the bottom of the roof.
Once that ridge exists, the meltwater arriving behind it has nowhere to drain. It pools, and now you have standing water sitting several inches deep on a roof surface that was designed to shed, backing up under the shingle courses and through the fasteners. That is how water ends up inside a wall or a ceiling with no storm anywhere in the forecast.
Elevation raises the stakes, since the Wasatch Back holds heavier, longer-lasting snowpack than the valley floor. That's part of why snow load works differently there. Ice-and-water shield along the eaves is the standard defense. Its grade and coverage is one of the quiet line items separating bids.
If attic heat drives the melting, then the fix that matters most is not on top of the roof. It is inside the attic.
A correctly ventilated attic pulls cool outside air in low, at the eaves. Lets warm air out high, at the ridge. The result is an attic that stays close to outside temperature. That's the roof deck stays cold. That's the snow on it melts slowly and mostly from sun rather than from your furnace.
Ventilation is a code item with a required ratio between intake and exhaust. It is the single most often skipped item we find. It is invisible from the street and easy to leave out of a bid, and in our experience roughly 90 of every 100 homes we go into are under-ventilated. Most of those homeowners were never told. Many of them passed a home inspection anyway, because inspectors generally do not measure the ratio. That gap is covered in why a roof can pass inspection and still be under-ventilated.
What you can do about it without hiring anyone: clear gutters and downspouts before the first freeze, check that insulation has not been blown over the intake vents at the eaves, run bathroom and kitchen fans so household moisture leaves the house, and pull snow back off the lower roof from the ground with an extension rake. If water is coming in now, start with the steps for limiting damage.
The same underlying problem shows up in July as an upstairs that will not cool down. That's why the attic is worth checking before you blame the air conditioner.
As a roofing contractor in Utah, my February calls are a different species from my July calls. In summer someone calls about a storm. In late winter someone calls because water is coming into the house and it has not rained in two weeks. They cannot make that add up.
It adds up once you know that a snowpack melts from underneath, where it touches the shingles. That's because heat is leaving your attic into it. Rain runs off in minutes; this puts days of standing water against your roof. Which means the thing worth fixing is usually not on top of the roof at all. It is in the attic, where the heat is getting out.
Here is the fair part: the crews who built most of these roofs were not being lazy. Ventilation is a code item with a required ratio, it is invisible from the street. It is so the easiest thing to leave out of a bid. Around 90 of every 100 homes we go into are under-ventilated. Almost none of those owners were told.
So Master Roofing bids intake ventilation to the required ratio on every job. And what you can do before next winter costs nothing: on a cold day, put your hand up in the attic. If it feels much warmer than outside, that warmth is what will be melting your snow in January.
This article is general information about Utah roofs, not an assessment of yours. Every roof is different, and no article can tell you what is actually happening on your specific house. Have a licensed roofing contractor look at it in person before you act on anything here.
Because your own attic heat is melting the snow from underneath and producing water on your roof without any precipitation. The snowpack acts as both the water source and the lid that keeps that water in place. This is also why the leak can appear during a clear, cold stretch. That's the opposite of when homeowners expect roof problems.
It reduces the water available to feed an ice dam and can buy relief in an active situation. But it treats the symptom rather than the cause. Do it from the ground with an extension tool, never from a ladder in winter, and treat it as first aid while you deal with the ventilation underneath.
Usually not. A leak that appears only in snowmelt tends to point at specific details plus attic ventilation rather than at a roof that has broadly failed. What changes that read is multiplicity: water in several unrelated places at once is a different conversation, covered in whether a leak is a small fix or a sign the whole roof is failing.
Heat cable manages the symptom by keeping a drainage channel open through the ice. It does not address why the melting is happening, it adds an electrical load every winter. It has a service life of its own. It has a real place on some roofs and some architectures. But installing it before checking ventilation is treating the smoke rather than the fire.
It is the right defense and it is required at the eaves for good reason. But it protects against water that has already backed up rather than stopping the backup. Grade and coverage width matter, especially at higher elevations where snow sits longer. The pairing that works is proper membrane at the edges plus ventilation that keeps the deck cold.
We're here to see what's going on with your roof. A real assessment starts with your history and your attic, not a number from the driveway. You'll get a straight answer about what's up there, what it needs, and what it costs. Sometimes the honest answer is: your roof looks great.