The Effects of Snow on Your Roof

Snow damages roofs by weight, not depth — and a foot of wet snow can outweigh several feet of powder. An Interlock aluminum roof adds almost no load of its own (~0.41 psf) and its smooth, four-way-interlocked surface sheds snow; one owner reported a 95% drop in roof snow load after switching.

Every winter the same worry returns for homeowners in snow country: is the roof going to hold? The answer depends on a number most people never think about — weight, not depth.

It's easy to judge a snowfall by how deep it looks, but your roof feels only the weight. A foot of dry powder is light; a foot of wet, partially melted snow can weigh several times as much and quietly approach what a roof was designed to carry.

That's where the roof itself matters. A heavy roofing material spends part of your structure's load budget before any snow falls, while an Interlock aluminum roof adds almost nothing — and actively sheds the snow that does land. Here's how snow really affects a roof, and why metal handles it so well.

## Depth Is No Indicator — Weight Is The single most important fact about snow on a roof is that depth tells you very little. Light, dry powder might weigh only a few pounds per square foot even at significant depth, while dense, water-laden snow — or snow that has partially melted and refrozen — can weigh many times more for the same height. Rain falling onto an existing snowpack is especially dangerous, because the snow absorbs the water like a sponge and its weight climbs fast.

## Why Older Homes Are at Risk Older homes were built to the framing standards and material expectations of their era, and decades of wear — sagging decking, weakened rafters, or a heavy existing roof already near its limit — can erode the safety margin. Piling a dense snow load on top of a tired structure is how problems start.

## How a Metal Roof Reduces Snow Load A metal roof attacks the problem from two directions. First, it weighs almost nothing: an Interlock aluminum shingle installs at about 0.41 psf, a fraction of asphalt or tile. Second, its surface is smooth and hard rather than rough and absorbent, so snow tends to slide off as it accumulates. One Interlock homeowner reported the snow load on their home dropped by 95% after switching. That same rigidity and light weight are central to why Interlock's roofing systems are engineered to be so strong under load.

Real customers in snow-heavy climates back up that shedding behavior. A homeowner in Erin, Ontario — a region that sees substantial winter snowfall and repeated freeze-thaw cycling — put it simply: "We're very happy with our Metal Shingles from Interlock Metal Roofing (Ontario) Ltd. in Erin, ON — the installer handled the job personally, cleaned up thoroughly, and the durable metal shingles give us confidence against Erin's heavy snow and freeze-thaw conditions; we have no complaints."

"We're very happy with our Metal Shingles from Interlock Metal Roofing (Ontario) Ltd. in Erin, ON — the installer handled the job personally, cleaned up thoroughly, and the durable metal shingles give us confidence against Erin's heavy snow and freeze-thaw conditions; we have no complaints." — Doug & Betty Delaney, Erin, Ontario · Installed April 2015 · Verified GuildQuality review

## Shedding Snow, Sealing Out Water The same four-way interlocking design that makes Interlock roofs strong also helps in winter. The panels present a continuous, mechanically locked surface with no exposed tabs to trap snow or let melt-water work underneath. That shedding behavior also reduces the conditions that lead to ice dams at the eaves, one of the most damaging side effects of heavy snow buildup.

## Strength for the Snow That Stays No roof sheds every flake, so what remains still has to be carried — and that's where Interlock's aircraft-grade aluminum earns its keep. The panels are rigid and impact-resistant (UL 2218 Class 4), so they handle accumulated snow and the occasional ice chunk without denting or cracking.

## Winter Peace of Mind For homeowners in snow country, a roof that adds no weight and sheds what falls is a meaningful upgrade. An Interlock roof delivers that, backed by the Guardian Lifetime Limited Warranty. Request a free quote and put a lighter, snow-shedding roof over your head.