Eavestrough on Blue Mountains chalets

The single fact that decides eavestrough on this escarpment is that a steep roof releases its snow all at once. A slab lets go, accelerates over twenty or thirty feet of pitch, and arrives at the eave with enough mass to flatten aluminum and tear hangers out of the fascia in one event. Owners often replace the trough, get through a season, and replace it again.

Replacing the section is half a repair. The other half is on the slope above it: snow retention placed so the pack releases in manageable amounts rather than in a single slab, or moving the trough out of the path where the roof geometry allows it. Without one of those two things, the new trough has the same life expectancy as the old one.

Where the trough does belong under a slide path, it sits higher relative to the drip edge than it would on a low-pitched roof, on tighter hanger spacing, so the load is spread and the water does not overshoot it. Standard spacing on a chalet is how you end up with a trough that is both flattened and, in summer, missed entirely by the water coming off the pitch.

Chalet roofs are rarely simple rectangles. Gables meet at valleys, dormers interrupt the runs, and shed roofs discharge onto lower ones. Every valley is a channel, and it delivers the water from two planes to a single point at the eave.

This means the roof area is the wrong number to size trough by. What matters is how much water arrives at each individual run, and on a complex chalet one short length of trough beneath a big valley can be taking more water than the entire opposite side of the house. Sized off total area, that run is undersized on the day it goes up and it overflows every spring while the rest of the system looks fine.

We size the runs individually and put the downspout where the valley discharges, not where it is tidiest on the elevation. Where a valley genuinely delivers more than trough can take, a kick-out and a dedicated drop is the answer rather than a bigger profile.

A downspout on a shaded north elevation up here can freeze solid in January and stay frozen. Once it does, the trough above it has nowhere to send meltwater, so it backs up, overflows at the corner and lays a sheet of ice across whatever is below. On a chalet that is usually a walkway, a deck stair or the path from the parking pad to the door.

Heat cable is the usual response and it treats the symptom at a running cost. The better answers are structural: put downspouts on the sun-exposed elevations wherever the roof allows, oversize the drops so a partial ice plug still passes water, and discharge clear of anything anyone walks on.

If the chalet is rented out, this is not only a maintenance question. A guest arriving in the dark onto an iced walkway is the incident that follows an overflowing trough, and the trough is the part nobody inspects. We would rather move a downspout during the install than have the conversation afterwards.