a house covered in snow

Snow Load Capacity and Your Roof (Podcast)

In this episode, John Maher interviews Brett Rogenski, General Manager of Master Roofers, about the importance of understanding snow load capacity on New England roofs. Brett explains how varying snow types—from light powder to heavy wet snow—affect structural load, and highlights warning signs like creaks, sagging, and leaks. He stresses the need for professional snow removal and roof assessments while considering local building codes, roof pitch, and insulation. This practical discussion offers homeowners valuable insights to ensure their roofs safely withstand winter's challenges.

John Maher: Hi, I'm John Maher, and I'm here today with Brett Rogenski, general manager of Master Roofers, the most trusted roofing company in New Hampshire, for over 80 years. Today our topic is snow load capacity and your roof.

Welcome, Brett.

Brett Rogenski: Hey, thank you, John. I appreciate you having me today.

Importance of Understanding Snow Load Capacity

Maher: Yeah, absolutely. Brett, what are some of your insights into the importance of understanding the snow load capacity for homeowners in New England on your roof, especially during the winter months? How much snow is too much snow for your roof to handle?

Rogenski: Yeah, that's a great question, John, and it's one that has a... Sometimes it's a challenge to answer because there's not just a number.

So, if you think about snow, we get light fluffy snow, we get heavy wet snow, we get sleet, we get rain, we get light fluffy snow that then gets rained on, you name it all and that sort of thing.

Maher: Yep, ice storms. Yeah.

Rogenski: Ice storms, yeah, exactly. And a lot of that has to do with elevation, just the type of precipitation that we're getting at any given time. So there's a lot of factors that go into that.

So, how much snow is too much snow on your roof? Again, it really depends on the type of snow, and I hate that answer because it seems evasive.

But think about it. We've all had that where we go out and shovel the driveway and it's six inches. It's that heavy, wet, feels like fresh-poured concrete snow, and that weighs more per cubic per square foot, if you will. And that nice light, fluffy snow that we got, and you might have 18 inches of it, but it's just like powder, you know?

Maher: Right, right. Totally different.

Rogenski: Yeah, exactly. But the thing I would tell you is all the snow on your roof typically eventually compacts down. So, if you were to go up and let's say you had a foot of snow on your roof that's accumulated over the last couple of weeks, the bottom part's going to be more like that fresh-poured concrete, dense, heavy because it's been melting and compacting.

And maybe we got some snow last night that it was nice and cold, it was nice and fluffy. So if you were to say if you're going to core sample, you probably got a little of everything in there and it kind of depends how much there is.

In New Hampshire, when we're figuring out snow load on a roof, there's a couple factors. And usually when we're talking, a lot of folks just say to me, well, they're like, "Well, what's code?" Well, code's different in every town, quite frankly is because of latitudes, longitudes elevations and that sort of thing.

So, each town usually calculates what their ground snow load is so that's a baseline. And then if you had an engineer, for instance, designing a home, he's going to find out what your address, what your town's ground snow load is, 70 pounds, and then he's basically got a formula he punches that into that says, "Okay, I need a roof that can handle at least X, Y, Z."

You know, as a general rule, I like to tell people that your roof's snow load is probably going to be designed to take somewhere between 20 and 30 pounds per square foot, but certainly sometimes it's higher. It really depends where you are, and it depends who you're working with, what your individual municipality's requirements are.

Maher: But if you think about that, that's per square foot. Foot's not bad.

Rogenski: That's of fresh powder, 20 pounds per square foot is probably two feet or more. Of that heavy snow, it might only be seven inches, that heavy water-saturated snow.

Does The Style Of Roof Impact Snow Load Capacity?

Maher: And then the amount that your roof can handle, I'd imagine it would have to do with the style of your roof as well, the pitch. A higher pitched roof is going to have more capacity for the snow to just sort of slide off so you're generally not going to have too much snow building up. Whereas a lower pitched roof or a flat roof or a commercial building or something is going to allow that snow to just pile up, right?

Rogenski: Yeah, it will. It will exactly that. So the steeper the pitch roof and then depending on the framing style as well, is going to help determine how much load that can handle. So typically steeper pitch roofs, because they shed the water more efficiently allow, dissipate a lot of that weight because that water leaves the roof, it melts and travels under, and then eventually leaves the roof much more so than say, a very low slope roof like you might see on a ranch home or a flat roof. So all those things affect that.

And again, when your house was built, especially if you're, let's say, going from the '60s onward, they calculated whatever the snow load was at that time for compliance with the local standards.

Warning Signs There Is Too Much Snow On Your Roof

Maher: So, what are some warning signs maybe that your roof might be struggling to support the weight of snow? And is there anything that a homeowner can do if they suspect that their roof is starting to become overloaded?

Rogenski: Sure. So first of all, you may start hearing creaks, groans, even cracking that you don't typically hear out of your roof, up in your attic or whatever. So, if we've had a lot of snow recently and then you start hearing your house maybe groan a bit and that you're not used to, that's not a good sign. That's a sign that you might want to take a look at that right away.

The other thing would be suddenly getting leaks where you've never had leaks in the past, because again, as that snow load makes, depending on your framing system, makes the trusses or whatever's under there flex, it can actually open up some of the seams between the plywood, et cetera, and suddenly you're getting water penetration spots that were perfectly dry before. So again, that's a sign that that roof is under distress.

And then what can you do about that? Well, the first thing you should do is call someone to remove that. In those situations, the immediate answer is removal of snow from your roof. So you're going to want to get with a qualified professional, someone who can get up there safely, continue to be safe.

You don't want to call your cousin's neighbor and have him go up and shovel your roof because guess what? If he falls off your roof, even though you're paying him 50 bucks and a six-pack to shovel your roof off, if he falls off that roof, that's going to come back on you and your homeowner's insurance.

So, you want to get a professional, make sure they're properly equipped to do that, will have proper knowledge and are properly insured, and you're going to want that snow removed.

So, for instance, we have, well, we've got regular shovels, but we have types of shovels that essentially they look almost like a sled. And we slide them under the snow, can bring them to the edge, remove it, and we can remove a lot of snow quickly, efficiently and safely using tools like that, and then at least to get that heavy load off and see what's going.

The other thing is if you start seeing bowing or sagging in your roof, that's another sign that your roof may be able duress. So, with a known heavy snow load, if all of a sudden you start seeing, wow, when I look across that roof, it kind of goes like this, and it never did that before-

Maher: Yeah, that's down in the middle. Yeah.

Rogenski: Yeah. That's probably between those rafters or those trusses, and it's actually got so much weight on it's pushing that underlayment, that plywood down and making it bow, that's a sign of imminent potential failure. So that's another visual cue.

What Can Be Done About Excessive Snow Load

Maher: And then that's the kind of thing you'd probably want to have a contractor come and look at. Maybe they have to put in some additional rafters or do something to strengthen your roof, right?

Rogenski: Yeah, absolutely. Yeah. The first thing you want to do is get that snow off, so alleviate that stress, and then absolutely get a qualified contractor in to look at whatever your roofing system is and see what the challenges are there causing that potential failure and address them.

So yeah, somehow that roof probably needs to be strengthened, unless it was just such a massive snow load that you're like, well, we will never experience this again.

What Can Homeowners Do To Prepare For Heavy Snowfall?

Maher: Is there anything that a homeowner can do to kind of prepare their roof proactively for a heavy snowfall?

Obviously once the snow comes down, if you have snow rakes, you could try to get the snow off or call a professional like yourselves to come and remove the snow from your roof. Is there anything that a homeowner can do to kind of prevent snow buildup on the roof?

Rogenski: Not a lot you can do to prevent snow buildup, but if you know, for instance, here we're in New England, we got a good nor'easter coming, let's say, and we know that, yeah, keep those soffits clear.

So, you mentioned snow rakes. Okay, so you can go, if you have a roof rake and you're capable of doing it, or you have a friend, a neighbor, or someone that you hire or that could come, make sure that you use that roof rake to remove the snow for those first two or three feet back from the edge of your roof.

And because again, what that'll do is it'll allow any melting to freely flow off and not create ice stains, which then creates more weight. So anything that you can do that'll help ultimately as that roof tries to shed that snow load do so more efficiently. So that's about all you can do ahead of time to do that.

Also, you want to make sure that your roof isn't already loaded, I guess would be the big thing. If we've had, I believe it was February of 2015 was the, as we called it, the 'snowmageddon' year, and it snowed a ton and-

Maher: And never melted and then just kept snowing on top of the previous snow and it just built up and up and up. Yeah.

Rogenski: Exactly. Yeah. So they might be talking about a foot of snow this weekend, which a lot of times you'd go, "Eh, okay, yeah, it's a foot of snow."

Well, the problem is if you've already got 18 inches or 24 inches of compacted snow on your roof, that's it. So you may want to, in situations like that, be proactive in seeking someone to get that snow removed before the next snowstorm comes because that could be the proverbial straw that breaks the camel's back, so to speak.

Maher: All right. Well, that's all really great information, Brett. Thanks again for speaking with me today.

Rogenski: Oh, thanks so much for having me.

Maher: And for more information, you can visit the website at masterroofers.com or call 603-623-4973.