Concentric Vent covered with snow

Dsisson

Guys, with all this snow in New England, I realized today that the vent/intake for my attic furnace was covered with snow. It terminates approx 18" above the roof, but is right next to a side wall and the snow drifted over it. I was able to clear it with a broom out the skylight (!!!) but am concerned for the long term. I'm guessing on a normal winter I'd still have some drifting snow at that area. I can extend it up, but wonder how high? Obviously, nothing is happening until the weather improves.

I'm right that having it covered with snow is bad, right?

Tinman

That's a tough one because of the conditions in the northeast right now. Most manufacturer instructions state 12" above anticipated snow level. How do you anticipate for the type of snowfall you guys are experiencing or the recent 19.3" we got got in Chicago?
I usually terminate around 30" above the ground but sometimes that isn't enough because the type of drifting you're describing. So what I always tell my customers is that it's their responsibility to keep any eye on the vent terminations in unusual snowfall/drifting conditions.
And yes, you did the right thing by clearing them.

icesailor

If you have snow drifting on your roof, the snow level must be really high. You need to take a roof rake and pull the snow down and off as far as you can from the edges. Because when the snow starts to melt, the water will "dam up" against the snow and work itself back under the roof and cause major leaks. Plus, when the edges are clear, the snow will often just slide off. If you get any amount of light rain. it is absorbed by the snow. The snow weight on the roof can cause it to collapse. THAT is a very bad thing.

Dsisson

The vent is poking out of the roof. It's on the 3rd floor, so really hard to get up that high to clear the snow. Luckily, I can reach the vent from a skylight - with a broom. This is the first winter with the new furnace & vent location - and historic snow levels. Most of the snow is blowing off the roof, but in some areas it's drifting and it seems to be drifting right at the vent. I'll keep an eye on it, and if it keeps being a problem I'll get it extended up once summer comes. Thanks for the advice
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BobC

The snow levels in the Boston area are unbelievable, we have had well over seven feet of snow in about three weeks and have had no meltin.

I have seen snow drifting over 7 ft against the sides of buildings. Everybody has to check any vents to be sure they are clear of snow.

Bob

KC_Jones

I would think dryer vents would fall into this category as well...especially gas dryers.

Paul48

That's a bad location. I'd bracket it off the sidewall, and raise it.

icesailor

For Plumbers in Massachusetts, when it comes to Plumbing Vents, you MUST be 10' away horizontally from a vertical surface (wall) or 24" above it. For that reason. Actually, if that skylight is less than 10' away, some AHJ might not pass it. The dangers of CO coming back while the window is open in the summer.

Do you have CO/Smokes as per MA Code?

Chances are, you may not ever see sow like that again in your lifetime. But you know what to look out for now.

Dsisson

I'm in Rhode Island, but your observations are correct. I may have to raise it regardless. Yes, I have hardwired/interconnected smokes/co.

icesailor

Usually, snow will only drift so high. Keep an eye on it. It might be OK.

Snow drifts on the Lee side of an obstruction. Look at a snow drift against a house and notice the snow angle. If the vent and the angle don't coincide, consider that. Also, the wind will start to swirl after the obstruction on the Lee side. That's why it is always bare on a snow covered roof after a drift from an obstruction. Or at least, usually.