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First time owning a house with a roof that can be raked, It is a shingled roof.

The question is - Should I be doing it?

We live in Northeast (it's snowing as we speak) and icicles do form on the roof in several places. I assumed I need to rake the roof and bought a rake. However, recently a contractor who did a the new roof on this house last year stopped by, and when I asked him about it - he said not to rake it! His reasoning was that I would just push up a potential ice dam higher on the roof to the location where it doesn't have a protection and I would only potentially cause a bigger problem. In other words, trading off a small ice dam near the roof edge to for a larger ice dam higher up the roof.

Is this legit or he's just looking to spread bad advise and get more roofing business? (kidding. I hope.)

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    I may be the only one who doesn't understand, but it may help future readers to include a brief explanation of what it means to rake a roof.
    – izzy
    Feb 9 at 19:07
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    Roof rakes are specially-designed tools for removing accumulations of snow.
    – isherwood
    Feb 9 at 19:20
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    If you have ice dams or more icicles than an unheated building, address insulation and venting next spring/summer/fall. Icicles are expensive without even getting into the expense of damages form ice dams - the heat coming out of the roof to melt the snow isn't free.
    – Ecnerwal
    Feb 9 at 22:50
  • @Ecnerwal: "the heat coming out of the roof to melt the snow isn't free." -- no, but it's not extra either. Snow is an insulator. If anything, heat losses when there is snow on the roof will be lower than without. Feb 10 at 4:06
  • Most roofs must hold a minimum of 4 feet of snow, safety factor for quite a few more feet. If wanting remove snow from shingle roof should leave about a foot on top of shingles. Frozen shingles will break easy, so a foot of snow will help protect them from people walking on them. Ice dams usually fixed by more insulation/ventilation is attic.
    – crip659
    Feb 15 at 16:08
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There are really two reasons to rake a roof (snow weight and ice dams), and there are two reasons not to rake (effort and roofing damage).

Raking to reduce snow weight
If you're concerned that the weight of accumulated snow will exceed load design limits, by all means pull some snow off. You don't want a collapse. This is a rare situation in northern climates, though, as snow loads are expected and accommodated in modern construction. Talk to your neighbors about how much snow is concerning. Take an average between the Chicken Little and the Couldn't Care Less types.

Raking to resolve or prevent ice dams
Whether you rake for ice dams depends on a number of factors, such as attic insulation and ventilation, sun exposure, and weather conditions. You'll have to make a judgement call on that for a given situation.

If you have an ice dam problem, removing the snow from the lower portion of the roof may help. By removing snow from the area that's melting you prevent dams from forming. If snow is melting due to inadequate insulation, and most of the heat lost from the home transfers through the roof down low, clearing that area may resolve the issue.

It may also relocate the problem, as has been suggested. Dams occur where ice has melted and re-frozen. If the snow is insulating the roof surface, allowing melting to occur due to heat from below, the dam may occur just below the new lower edge of the snow.

Raking is hard work and damages roofing
All that said, raking is hard work. You'll get a six pack. It also will damage your shingles if you're not extremely careful--those corners have a tendency to punch through the snow on occasion. Over time you'll scrape away the protective ceramic granules and weaken the shingles. They'll curl and crack before they otherwise would have. Raking is to be avoided unless truly necessary.

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    If you're raking to reduce weight, you can (in theory) avoid shingle damage: just leave a few inches of snow on the roof.
    – Mark
    Feb 10 at 8:06
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    As an additional comment on raking to reduce snow weight, it is also good to keep in mind when you might want to do so. Snow buildup in cold weather is no problem since it weighs nearly nothing. When you may want to consider raking is when it gets warm (e.g. melting) and you still have a thick layer of snow — wet snow is heavy.
    – Etheryte
    Feb 10 at 9:57
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    @Etheryte if the same snow has started to melt, there's the same amount of water, just compressed into a thinner layer. If it's slipped down the roof the local loading will have changed, and if rain has partially melted it, that will have added to the mass.
    – Chris H
    Feb 10 at 11:41
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    The point is that 20" of snow in March is likely to weigh much more than 20" of snow in January. Density can vary by double or more.
    – isherwood
    Feb 10 at 13:26
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    +1 Raking to stop ice dams is an emergency management procedure - you shouldn't be doing this year after year. The roof needs to be repaired if it is damming. Poor insulation and air leaks are a typical cause. Improving attic ventilation can be a stopgap. For low slope roofs, ditching the shingle for a flat roof membrane system is ideal. Even with water&ice shield under the shingles, a roof that is ice damming will leak.
    – J...
    Feb 10 at 19:15
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You should not be touching your shingles when raking. If you have 5" on roof you don't need to touch it. If you have 24" on roof you don't need to rake the last two inches. Also rake in the early morning so sunlight helps distribute water/ice better.

There isn't general advice to give because it is dependent on the amount of snow on your roof, pitch of roof, and what the upcoming weather looks like. But you should not be touching asphalt shingles as this will actually not only damage shingle but you will sure push snow under them.

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  • Thank you! So, are we talking about constant raking that would damage shingles or only once would already cause damage? I only raked it once (it was a foot of snow) but I definitely got it all the way to the shingles... The water damage is not an issue because it all has melted since (multiple times), but did I damage the shingles and it would require repair? What actually gets damaged - some sort of coating? Or is it moving the shingles?
    – user129995
    Feb 10 at 1:19
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    @user129995 - there are two ways to damage the shingles. To literally bend or break them or to rub off their top layer which protects them. It is a given that you should be careful and not "break" your shingles. Rubbing off the top layer takes time but does happen with people that want to sweep their roof - seen it - or things like raking. You would not have "damaged" your roof with one raking. Remember you are literally doing nothing removing the last couple inches of snow, other than risking issues.
    – DMoore
    Feb 10 at 4:05
  • How would you rake and manage to not remove the last two inches? Seems that raking the snow above the last two inches would pull the last two inches off with it... Feb 10 at 6:18
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    @JimmyFix-it - it just means you don't slam the rake down on your roof and pull. I have used different rakes many times and you can easily start off middrift and pull down slow and have a good 1-2 inches left, albeit more compacted. There is definitely a technique to it.
    – DMoore
    Feb 10 at 6:31
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As others have said, whether to rake or not depends on your circumstances.

See the picture: I have a steep poorly insulated roof over my home that extends out over an unheated garage and becomes more shallow there. Snow melts on the steep part and water flows down under the snow to the unheated shallower roof where it refreezes and forms a dam anywhere on that part of the roof depending on the depth, weather, rate of melt and so on. So I rake the flatter part of the roof over the garage as you can see. This allows the sun to do the work and keep the water from the warmer part of the house flowing.

I would probably rake higher but that's as far as I can reach with my 24 foot rake.

You should consider the slope, depth, current and forecast temperature, amount of sun, etc in deciding.

Other considerations:

  • Raking is REALLY hard work. So laziness is a factor. I only do it if i REALLY think it's necessary.
  • If you're going to do it, do it ASAP. As soon as there is 4 or more inches, do it incrementally, or if you don't have the chance, do it as soon as you can after. Once you get a single 24-hour cycle of sun and freeze it becomes nearly impossible, or at least, 3 times as much work.
  • Think about what's below. If it's grass, great. IF it's a walkway or a driveway, you need a snow blower. Bear in mind that the raked snow will form a heap of heavily packed snow where it falls. And you'll be mighty tired. You won't have the energy or motivation to clear it off the walkway, and if you leave it overnight, it'll be there til spring. If you're raking onto a walkway or driveway you need a snow blower.
  • Don't damage your roof. You don't need to rake everything. Let the sun finish the job.
  • I recommend the rake I bought, not sure if it's ok to name it here so I won't but it has teflon wheels that ride the roof and slices the snow off just above them.

enter image description here

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    This is very helpful, thank you! Did not know there are rakes with wheels, I think that would solved the concerns with damaging the shingles, right? Why would they even sell the rakes without wheels then?... Those definitely scrape to the very shingles.
    – user129995
    Feb 10 at 1:23
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    Good advice. Note the wheels can still damage an asphalt roof especially if they get caught but way way better than one without.
    – DMoore
    Feb 10 at 5:03
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    They sell rakes without wheels, @user129995, because they're cheaper and people like cheap.
    – FreeMan
    Feb 10 at 14:51
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    If I ever buy another house in New England and there's even a hint of ice dams, I swear I'll have a metal roof installed :-) Feb 10 at 16:53
  • Truly, all that it needs is proper insulation and ventilation. As it happens, my roof is metal, too, but it has zero icicles (a few hanging ice sculptures from when the snow slid down a couple of feet without breaking off on a warm day.) That's because it's well insulated (to keep the heat in the house) and well vented (to keep any house heat that does escape from impacting the roof.) It's also speced for 10 PSF more than the "code minimum snow load" for the area, which keeps me from fretting about raking it due to weight (which would be difficult as heck to do...)
    – Ecnerwal
    Feb 11 at 14:24
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Whether to rake the snow off the roof or not depends on temperature during the day, the time it will take the snow to melt and when the next snowstorm is expected. At my house in the Berkshires, Western MA, one year we had so much snow on the roof and extremely low temps that we got an ice dam. Had to hire someone to clear the roof. This required clearing the decks to make room for the snow and then clearing the roof and a few repeats of this process. 5 hours, $500 cost. Money well spent as it saved my back. In addition, the snow on the roof was about to cover the stink pipe. The next snowfall would have caused plumbing problems as well. I then purchased a Minnesnowta roof rake and started clearing the roof anytime when more than 1 storm was expected in the coming week. There are no tines on this rake. It moves on 2 nylon wheels and uses a PVC sheet to free the snow and allow it to slide down. The bottom most layer of snow on the roof is usually compressed enough that the wheels on the rake do not go through that layer and never touch the roof shingles. It is hard work but some years, it was necessary to clear the roof and the decks.

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  • I have that rake it's great. Yes lots of work. Clear, rake, clear, rake, clear, wait for the next storm :). I love how the snow comes down in giant bricks and sometimes hits you. Good fun if you love snow.
    – jay613
    Feb 16 at 21:15
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Roof raking is a pain (especially in nasty winter weather) and has its cons, as others pointed out. Better to avoid ice dams. Consider putting heating cables in the gutters/downspouts and place the cables zig-zag on the edge of the roof to avoid ice dams forming. Also, use covers on the gutters to avoid the gutters getting clogged with autumn leaves. Clogged and frozen gutters mean that the water that melts off the roof has no good place to go. The melting water overflows the gutters and causes icicles, sometimes quite large and dangerous to anyone standing under them. (If you replace the gutters, think of using a larger size. Older houses may have undersized gutters.) The heating cables can be thermostat or switch controlled. In my experience, ice dams are a rare occurance. If you are getting frequent ice dams, there is a problem that should be fixed. See, for example, https://www.thisoldhouse.com/roofing/21017660/how-to-get-rid-of-ice-dams

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