Home Forums Hunting & Shooting Alaska Calculating Snow Loads

Gladly take some snow down here.

Alyeska is rockin' - 24" of new at top in past 24 hr.

SBSs truss plant roof in Fairbanks failed in the 90a, pretty ironic.

The warehouse roof failed about 4 years ago, a portion of the roof collapsed on the main building about 2 years ago as you stated.

After the warehouse roof failed they "inspected" the roof on the main building. Apparently their X Ray vision was not working and they missed the wet foam. One would have to open it up to inspect that, musta thought it was a OK. LOL

Hard to see wet foam from the top side.

I think the truss plant roof failed due to a plugged roof drain. Big pond = point load.

Home trusses rarely fail.

No surprise, metal roofing does not add strength to the assembly.

Structural strength comes from truss design and plywood' OSB overlay. Neither do asphalt shingles add strength. Quite the opposite they only add weight.... metal is lighter... and expense in material maybe, tho I think the material and labor expenses might nearly cancel out between metal and asphalt.

Flat-topped tarred roofs in snow country..... Well!

On gable roofs, metal roofing sheds snow load easier, expecially at high angles. I went 4/12 and 5/12 metal on roofs that i had say in. 6/12....No problem! At least with metal. Which I love when it's raining. My wife doesn't like it for the house. Should re-shingle next summer- she won't countence anything but asphalt. W

It's a 4/12, and has ice-damming tendancies. I DID NOT design and build it. I think he was from So Cal or AZ or someplace warmer...I'm getting old enough to dislike dealing with that chit every winter. I'm working on her, but she is the definition of stubborn...and she doesn't have to do the roof-clearing thing. Soon, neither will I! I'm 75 now.... She's probably trying to kill me off.....

A friend over in Hope, AK ( wet snow country!) built his log house with snow dams on the roof to not shed snow. The roof is designed to something like 200 lbs/sq foot as a WAG.... maybe more. He didn't do things by halves. Water off the roof in spring/early summer was fine. Snow berms around the perimeter were not. I bought the oxpho-blue to blue the steel beams. . Barring a really catostrophic earthquake or fire, that log house is gonna be there for centuries. Excellent "rustic" taste and craftsmanship everywhere.

Some rich fugger from Anc or someplace will pay a pretty penny when his widow moves on. She was supposed to be here today, but snow/avalanches/power outages between here and there changed plans.

I have installed and removed a number of metal roofs.
No longer a fan unless its standing seam.

Even then, personally I would not have another on my own home.

The typical 3 foot wide "AG" panel with a thousand holes that you hope are sealed with a neoprene washer are good for dog houses and pole barns.

In cold parts of the state, it takes several things for a metal roof to shed, above 32 temps and damn steep helps, however even a 12/12 pitch will not shed reliably unless it accumulates or warms up.

Nor does it add the extreme weight, compared to metal, of a standard composition roof.

The difference in weight between metal and composition roofing is pretty inconsequential.

Trusses are designed based on live / dead loads.
Typical dead load is 10 pounds per square foot.
Live loads based on the environment, so to speak.

The thinking years ago is metal roofing could be installed on purlins.

Eliminating plywood and felt paper does add up when compared to a comp roof. Still inconsequential in terms of a properly engineered truss.

On a home, plywood with ice and water shield should be used if you want to avoid leaking light fixtures. Especially if using AG panels.

In most places of Alaska a metal roof and siding is the strongest and most economical way to go. A shingle roof would blow away the 1st fall in Bristol Bay,,I've seen it !! The gusset type style of pro-panel (the standard) is enormous and I havn't found properly torqued screws not to be a problem. I peeling off the cedar clapboard on our 20X24 and sheeting it this summer just for wind shielding alone.

Tend to disagree in regards to most part of the states but do agree in areas of high winds, low pitch roofs and minimal overhang's in those areas will withstand wind better.
Typical propanel screws are # 9 0r #10 X 1", in areas with sun and Bristol Bay may not be one of those, the small screws tend to loosen from expansion & contraction of the sheets, unless the lengths are kept short, especially if darker colors.

Once the screw is worked loose, the washer leaks, soon to be replaced with a #12 screw and finally a #14 and when that strips...... its caulking....
What a great roof, a sheet of 30 gauge metal with a million holes....... and relying on washers, great for dog houses and pole barns..... if you need metal go with a standing seam or klip rib system if you want something to last.

FYI, I have seen plenty of sheets of tin blown off of roofs or folded over in the villages.

John, have you noticed that roofing metal has gotten even thinner gauge?!

Alaskan suppliers oughtta be ashamed of the uber-thin sht they're selling

From my experience the typical panel from SBS, Northland wood, uresco and now the box stores has been 29 / 30 ga for awhile.

26 is usually a special order, although I think All Steel stocks 26ga coils nowdays.
Most people don't want to spend the extra money for the heavier gauge.

And, if its on plywood, it's ok.
If it's over purlins, you can sure tell when you're walking around on it!

Wonder what gauge is on our barn from the 70s. I know back then no one drilled, and you should could blue your thumb trying to start lead head nails sometimes with the bounce and miss. need to ospho that barn and repaint the galv a few years ago but keep running short of time..

Good question, I have a few old buildings with old roofing, but never pondered the gauge of the metal.

When they use to nail on metal roofs, they would nail through the "high hats", the tension of the rib on the washer was good enough, and they rarely leaked because the water ran down on the low part of the sheets and there were no holes in that area.

Didn't make a lot of difference if they washers under the head of the nails were a little loose.

Once they started using screws the manufacturers recommended installing on the flats because people would overtighten and spread the sheet.

They also got real specific about not over tightening the screws and deforming the neoprene washers.

I did a roof for a guy that worked for Ghem Co years ago and he wanted me to put the screws on top the ribs, which I did. Took me awhile, but I now know why!

So it was a bad truss design..

Not that it's germane to a snow discussion, but I put oldschool corrugated on the leanto of the barn...deep round wrinkles and 24ga materal. Very sturdy stuff...my kid and I could carry 26' panels at midspan with no threat of buckling. We used a springloaded center punch to mark screw holes on chalklines on the rounded peaks in a pattern, and the boys drove screws with drivers and finished with a 1/4 drive ratchet to lightly compress the washers. Screws were newer ones with a potmetal head that had an integral cup for the washer, which contains it from overcompression somewhat. Good product.

The batten-cap product on the curved roof part of the barn was 22ga...and it's HEAVY.

None of these were ridiculously expensive, or so it seemed. They're not comparable in any way to the delta rib material we removed from the leanto - don't know the gauge but that stuff would crease if you looked at it funny.

Vek, that barn you did is awesome!

The long sheets that wanna kink I'll roll up and put two or three bungee cords around them to carry or slide up over the edge of a roof, especially if I'm working alone. Stiffens them right up.

Vek's barn...

I remember that thread. That looks fantastic!

And notta easy chore

Veks Barn Roof Thread

Thanks for the link, cool thread that I hadn't seen.

We had a new year's party in there this year. 60+ folks inside, a couple of patio heaters, and it was comfortable pullover/sweatshirt weather indoors for all at 36F ambient outside. Haven't done much else to it other than clean up/palletize the decades of accumulated stuff inside. Lots of relics inside...my inlaws' family wagon (as in: towed behind horses) that's in great shape, the front axle/dolly of another horse-drawn cargo wagon (that rolls around as if it's on ball bearings), an old drag saw, a bunch of horse and ox tow rigging, old hand-farming tools, etc and so forth. I'm not a big decor guy and even less of a perpetually-shuffle-$hit-around-to-refine-storage guy, so need to figure out what to do with all of that stuff. Structure is dry for the first time in decades.