Roof shoveling...yes or no?

[graham418]

Typical roof in Quebec. Steep pitch, so the snow will slide when it builds up too much, with a little kicker at the bottom to shoot the snow away from the door.
Those old timers weren't so dumb.

 

[Talisman]

Here's what I have witnessed a few times. Heavy snow fall followed by some rain and roof damage all the way to collapses abound from old homes and barns to big box stores. If your roof has an insulation issue the deep snow can cause strange leaks as snow melts and refreezes infiltrating roof penetrations. There was a home in Stratton Mtn, VT that exploded when the sewer vent lines got blocked by snow and the sewer gas percolated through the traps into the home and finally ignited. Be smart about deciding to shovel or not shovel.

Those Quebec homes have simple roof lines and standing seam roofs, so there shouldn't be issues. Some home owners select designs by architects that may not think through the snow accumulating on the complicated roof lines and the type of roof material selected.

 

[scott43]

The snow load here in the building code is based on the 1 in 50 year snow and 1 in 50 year rain combined. It can be pretty big..anywhere from 30-90 lbs/sq ft. Roof failures don't happen that often so I wouldn't be overly concerned for most winters. There are factors in our code as well for roof design, pitch, etc but they are somewhat objective.

Talisman also makes good points..experience in design and maintenance are important as well. I look at new houses with all the complicated rooflines and they just don't make sense in this climate. So hard to re-roof properly and just seem like invitation for leaks.

 

[mcpowell]

Here’s the YouTube video I mentioned earlier.

 

[cantunamunch]

Here’s the YouTube video I mentioned earlier.

I wonder if he could have made it more gradual with webbing instead of rope, by putting a couple of twists into the webbing frex.

 

[Bruuuce]

First thing we were taught in first year Civil Engineering shoveling causes more residential roof collapses than not shoveling. This has to do with how the roof is cleared. Generally, most clear from the edge of the roof first focusing on one side (because it’s easier) but this causes high structural loads as loads become unbalanced resulting in roof failures.

Ideally if you shovel, clear from the middle first and then the edges ensuring both side of your roof get cleared equally at the same time is the generally the best advice.

The second bit of advice is don’t fall off .

I was hoping there was an engineer out there. Thanks for the info!

 

[Bruuuce]

What are your neighbors who are old timers in the area doing? (or do they have really good insurance?)

It is a mix in our neighborhood. Some shovel, some do not. We do have insurance that covers this issue, just in case...

 

[Bruuuce]

We normally have two or more feet of snow on our roof. I worry a bit as it starts to get higher, but we've never attempted to shovel it. It's approached four feet a few times. Feb 2017

View attachment 63400

Cool house!

 

[BS Slarver]

My .02 - from my time repairing / replacing collapsed roofs and having clearing more than a few in the Northeast - not one homeowner was successful in being compensated for any damages from a roof failure. All of the insurance company’s stated the homeowners
“ failed to maintain their property “ so an assessment / inspection certainly doesn’t hurt.
Perhaps consult with a structural engineer on your roof system. Is it truss or rafter ? What centers are the roof members ? How thick is the plywood ?
In designing our new MT home we spent time with structural engineering to insure the snow load was overkill so the 55+ Homeowners would never have to shovel it and if for some reason the skies unloaded with snow followed by rain the pitch was shallow enough to walk on.
As stated earlier you won’t damage your roof by walking out on it but you certainly want to keep feet and shovels out any valley or intersections where two roof pitches come together.
The point of proper clearing is valid. If doing it yourself don’t pile it at the eaves push it off or work in a line. Lastly with all that snow going to the ground be careful of the trees, bushes doors and windows below.
All that champagne powder shouldn’t be that hard to move

 

[scott43]

Case in point..older roofs here typically have 1"x6" plank roof sheathing on top of 16" centred 2"x8" or 2"x10" rafters with roof pitches above 30 degrees. I don't think shovelling could possibly be necessary on those. New houses, code is 3/8" OSB on 24" centres and a lot more truss roof structures. You can step right through that OSB on older roofs if you're not careful! And they've flattened the pitches a lot with much more elaborate roof details to adhere to max height zoning limitations.

 

[Wilhelmson]

If you have to ask at least grab a six pack, roof rake, and maybe 20 foot ladder and go at it for a couple hours. It's a fun winter chore to do with your spouse and then you get to warm up!

If there's any possibility of rain the potential ice dams on an asphalt roof warrant a raking. We never had an issue until we came back from February vacation and there was 2 feet of ice on the roof. We had minimal leakage but many others had big time problems, mold in the walls, etc.

For a metal roof it seems an engineer would have to look at your rafters. If your home was built in the 1980s might be better to let it collapse.

 

[skidrew]

Here’s the YouTube video I mentioned earlier.

Kind of omits the part about getting the rope up over the top of the snow . . .

 

[cantunamunch]

Kind of omits the part about getting the rope up over the top of the snow . . .

Throw bags are a pretty generic rescue/kayaker product these days?

 

[skidrew]

Throw bags are a pretty generic rescue/kayaker product these days?

Sure, but if the point of the video is a how to, they might start with that. Otherwise it's just a "cool - let's make a roof avalanche" video.

 

[Talisman]

Not really shoveling but a picture of a snowy roof I took last winter.

 

[oldschoolskier]

The snow load here in the building code is based on the 1 in 50 year snow and 1 in 50 year rain combined. It can be pretty big..anywhere from 30-90 lbs/sq ft. Roof failures don't happen that often so I wouldn't be overly concerned for most winters. There are factors in our code as well for roof design, pitch, etc but they are somewhat objective.

Talisman also makes good points..experience in design and maintenance are important as well. I look at new houses with all the complicated rooflines and they just don't make sense in this climate. So hard to re-roof properly and just seem like invitation for leaks.

OMG. It’s been reduced again. In the late ‘80s it was reduced and there was concern (and a couple of issues when hit the old levels, that had never been hit), now it’s even lower (haven’t been in the building industry for a while). While I understand that we are getting less snow overall, we are getting more extremes and subject to worse conditions in a short period over a gradual build over a season. I expect we will see some tragic failures at some point just to save a few dollars.

This is an intelligence test and someone is failing , glad my hoist was built in the early eights and our cottage in the late 70’s. We,be had 4ft of snow on the roof recently just south of Minden ON at the cottage 2 years ago and this is definitely more than the 50 year loading.

 

[Wilhelmson]

In 2015 when there were at least 71 roof collapses in MA, I didn't hear of any that were homes, most were big flat roofs. There must have been a few and a lot of snapped framing. The 100 and 200 year old homes are still standing for a reason.

 

[skidrew]

In 2015 when there were at least 71 roof collapses in MA, I didn't hear of any that were homes, most were big flat roofs. There must have been a few and a lot of snapped framing. The 100 and 200 year old homes are still standing for a reason.

Yes - things were overbuilt then because engineering wasn't as precise. More costly, but with an advantage.

 

[Doug Briggs]

I've shoveled my roofs (had to check the spelling ; roofs or rooves, both are acceptable) in big snow years. I've also fallen off a ladder removing ice and snow from a friend's roof. Removing ice and snow by shoveling is extremely dangerous. I avoid it when possible. The season of 10-11 was extraordinary. I cleared my porch roofs more than once. I also have solar panels on my house roof which unloads a lot of extra snow onto the porch roofs below.

I'm much more concerned about ice dams than roof loading. I use a snow rake whenever possible these days to get the snow off the edges of the roof where ice dams build up. My goal is to remove enough snow to the roof so that the sun will remove any existing ice build up. It is a matter of keeping up with it so it doesn't become an issue as neglect is the biggest problem. The roofs I have to clear are about 8 feet of low angle porch roofs. I can uncover 3 feet or so with the rake from the ground which is a significant portion of the load. In huge years, I'll go out a window to access the roof and am extremely cautious about my position on the roof as well as letting people know I'm doing it and checking back in with them.

 

[skix]

Saw the below and thought of this thread. Use care.

https://www.summitdaily.com/news/re...nal-snow-year-and-now-slides-and-some-deaths/

First, the bizarre circumstances of the death of a 25-year-old man who was shoveling a low-angle roof with a companion on Saturday at a housing development near Crested Butte. According to a preliminary report by the avalanche information center, no one noticed the roof avalanche for about 10 minutes.

Help was summoned, and their bodies were located by probes. The second snow shoveler, a 37-year-old man, who had not been buried as deeply, was treated for hypothermia. They had been buried for 20 to 30 minutes.

This was in a subdivision about a mile south of the town of Crested Butte. Another roof avalanche buried a 28-year-old man the evening before in Mt. Crested Butte, the town at the base of the ski area. He was treated for low core-body temperature. Yet another roof shoveler had been rescued from a roof avalanche the weekend before.​