Many commercial buildings in SC have flat roofs. I wonder how that would work in cold climates?

[raccoon]

I guess they don't have flat roofs in areas where there's heavy snowfall?

[MineralMan]

1. Actually there are lots of flat roofs here in Minnesota,

especially on commercial buildings. They're designed to handle the snow loads. One in a while, one collapses, but it's a rare event.

[laundry_queen]

6. Same here in Canada

if it's a particularly heavy snow year, some poor person gets sent to the roof to shovel.

[Brickbat]

2. I live on the North Shore of Lake Superior and we have an almost flat roof.

In very snowy years, we shovel it, but otherwise it's fine. As far as commercial buildings go, the vast majority have flat roofs -- single-story malls, high-rises, warehouses, apartment buildings, whatever -- so I'm not sure what your concern is.

[raccoon]

8. I was wondering if they built commercial buildings with steep roofs, or did something else. nt

[SidDithers]

3. My (rented) 40,000 sq ft warehouse has a flat roof...

most industrial buildings up here, near Toronto, do.

Sid

[hedgehog]

4. We have plenty of flat roofs up here in the Central New York snow belt.

In fact, my house (c.1880) has a flat roof. The difference is that they have to be reinforced to be able to handle the snow load.

"In Central Square, where about 7 feet of snow had fallen since the beginning of the month, officials were concerned the roof of the 24-hour Wal-Mart wouldn't hold up to the heavy load. The company called in a structural engineer to inspect the roof Thursday night and nearly a dozen workers have been removing snow by hand for nearly a week from the store's 152,000-square-foot flat roof.

The store also had roof problems during a heavy snow in February 2003, just a few months after it opened.

In Mexico, the First Methodist Church canceled its Sunday service as a safety precaution because of snow"

http://www.usatoday.com/weather/stormcenter/2007-02-16-lake-effect-snow_x.htm

Our biggest problem with the flat roof is that it tends to leak. The seams open up in hot weather. We will be putting on a peaked roof once we clear the mortgage. Our barn roof is slanted, but not enough to shed the snow. In the old days, the heat shed by livestock melted the snow off most barn roofs around here. Since our barn holds antique automobiles instead, my husband gets up on the roof as needed and shovels it off.

[slampoet]

5. Flat roofs suck in heavy winter but some short sighted people build em anyways.

[Johnyawl]

7. There's no such thing as a "flat" roof.

If a roof was flat, even in SC, the water wouldn't drain off of it.

All roofs are either "steep slope", or "low slope". Any roof with a pitch of 4/12 and greater is "steep slope"; roofs with a pitch of less then 4/12 is considered "low slope".

90% of all commercial structures in the US are low slope roofs. They're not designed or built by accident. They are designed by architects, with plans reviewed by structural engineers and roofing consultants, to ensure proper drainage for the climate the building is built in.

Johnyawl,
Roofing Consultant

[raccoon]

11. You'd be surprised how water drains in SC! Different from the other 49. Seriously, thanks. nt

[Worried senior]

9. We live in a trailer or mobile home

the roof isn't completely flat but slightly rounded. Get lots of snow on there but if the sun is out it usually melts off with no problem.

Neither one of us are capable of getting up there to shovel so we hope for the best, so far so good.

[backscatter712]

10. In areas with huge amounts of snow, a steep roof would be useful...

My impression is that the purpose of those roofs is to ensure that snow slides off the roof instead of caving it in when it's three feet deep.

Here in Colorado, there's a lot of flat (or to be technical, nearly flat) roofs, but a few years ago, a snow storm that dumped three feet of wet, sloppy spring snow caused some roofs to cave in.

[Romulox]

12. I'm no builder, but flat roofs are limited to steel and concrete (i.e. generally commercial)

buildings here in Michigan.

I'm not sure that I've ever seen a flat rood ("low sloop", per a knowledgeable DUer) wood structure in Michigan, which leaves out 99% of single-family homes.

[KG]

13. you would just engineer the roof to handle the load.

tricky part is deciding what a worst case scenario would be...