Steel sheds snow. Snow guards decide when and where.
Worth being straight about it: snow and ice on a metal roof do not behave the way they do on asphalt. A shingle surface is rough and grips the snow, holding it where it lands. Steel is smooth and sheds — which is most of the point of it — and that means a load can release in one go rather than sitting there melting quietly away. That is a genuine drawback of a metal roof, not a footnote. It is also entirely manageable, and the way you manage it is snow guards.
A snow guard holds snow on the roof. That is the point of it.
Most people assume a snow guard helps snow come off faster. It does the opposite, deliberately. Snow guards hold the pack in place so it melts down gradually and runs into the gutters over days, rather than letting go all at once. You are trading a sudden slide for a slow melt — and above a door, a walkway or a parked car, the slow melt is what you want.
Where they go
This is a conversation to have with your roofer before the roof goes on, not after the first slide. The places worth planning for:
Any entrance or doorway. A back deck or barbecue area. A hot tub. Over the garage door and the driveway — so you are not shovelling a foot of snow that just came off the roof and landed in front of the car. Paths and walkways you actually use in winter. And anywhere pets go out in the winter months.
How many, and exactly where, comes down to the geometry of your roof — which slopes shed onto what. That is a site-visit question, not something to work out from a drawing.
Two things decide whether a snow guard is any good
Neither is the shape of it, which is the part people look at. There is a simpler way to think about both: a snow guard should be built to the same specification as the roof it is bolted to. On a Wakefield Bridge roof that means two things.
Galvalume, not plastic. The shingle itself is Galvalume — a zinc-and-aluminium coating over steel — and the guard should be the same. Plastic goes brittle under years of sun, and a heavy release, a foot or two of snow letting go at once, can crack one and carry it off the roof along with the snow. A snow guard has to hold a load in year twenty-five as reliably as it did in year one.
A Kynar 500 coating. This is the one almost nobody asks about, and it is where a cheap guard gives itself away. Wakefield Bridge shingles are finished in Kynar 500 resin-based PVDF paint — the top of the range for metal roofing — so a guard finished in anything less will age at a different rate to the roof around it and start to show.
Kynar’s record is unusually well documented, because the industry has been leaving samples outdoors and photographing them for decades. There is a test fence in South Florida — about the harshest ultraviolet exposure in North America — that has been running since 1967, with half of each colour chip covered so the two can be compared directly. After fifty years the exposed halves still hold their colour. A separate fence built by a Japanese steelmaker in 1981 found that after fourteen years, Kynar was the only coating on it that still looked like itself.
The usual cheaper alternatives — silicone-modified polyester and similar — have ten to fifteen years of that kind of data behind them, and they chalk and grey as they age. Because snow guards sit in rows across the most visible part of the roof, that is precisely where you would notice it. A good roof at year fifteen with a line of washed-out hardware along the eave is a self-inflicted problem, and avoiding it costs very little at the point of specification.
The guards we fit are colour-matched to the roof, so they read as part of it rather than as something added afterwards.
How they go on
On a Wakefield Bridge roof the manufacturer sets out the method, and we follow it. Guards go along the eave in two staggered rows, each one seated against a horizontal shingle joint, spaced no more than twelve inches apart. On a steep roof, or one with long rafters carrying more snow, they go closer together.
Each guard is bedded on a continuous bead of sealant, pressed down onto solid backing, and fixed with three screws through the base. Every screw carries a neoprene washer, tightened until the washer is compressed by about half — enough to seal, not so much that it is crushed. That washer is the part standing between a fixing and a leak, and it is a small component doing a disproportionate amount of the work.
None of that is difficult. It is just exacting, and it is the difference between guards that are still holding snow in twenty years and guards that come off in the first bad winter. How those details go on a roof more broadly is in our installation process.
